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1

Hydrogeological Environments  

NSDL National Science Digital Library

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

Riemersma, Peter

2

Pedology: A Hydrogeological Perspective  

Microsoft Academic Search

The focus of pedology is on the nature of the solid phase of the near-surface portions of the earth's crust, while In a finite earth with concerns about sustainable use of natural the focus of hydrogeology is on the liquid phase. How- resources, earth science disciplines are moving toward appreciating their respective roles in understanding the interlinked functioning of ever,

T. N. Narasimhan

2005-01-01

3

ESCI 339: Field Hydrogeology  

NSDL National Science Digital Library

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.

Sanders, Laura; Department Of Geology, Northeastern I.

4

Hydrogeology Research Project  

NSDL National Science Digital Library

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.

Kulkarni, Tara

5

Coral reef hydrogeology  

SciTech Connect

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.

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

1985-05-21

6

Hydrogeology of Government Marsh  

SciTech Connect

A hydrogeologic investigation was conducted at Government Marsh located in St. Joseph County, Michigan from May, 1988, to November, 1993. Information on glacial geology, topography, drainage patterns, hydraulic conductivity, vegetation, water chemistry, and static water table elevations have been collected and analyzed. Data was collected in order to determine directions of ground water flow, and areas of recharge and discharge relative to the relationship between Government Marsh and the local ground water system. Bail-down tests, grain-size analysis, and permeameters were used to determine hydraulic conductivity in both the substrate adjacent to and upon which the wetland is situated, and relative to depth within the wetland. Water table elevations and chemistry were analyzed from wells adjacent to the wetland perimeter and within the boundaries of the wetland. The chemistry of rain water and wetland surface water was also analyzed. Results show that ground water is generally flowing northeast and south from Government Marsh and that most of the wetland is an area of ground water recharge. Government Marsh can be described as a northern bog according to vegetation and water chemistry. The surface water chemistry of the bog is acidic (mean pH = 3.99) and very low in dissolved solids (mean conductivity = 45.3 [mu]S/cm). Much of the vegetation in Government Marsh is of a type that thrives in low nutrient environments.

Kasenow, M.C. (Eastern Michigan Univ., Ypsilanti, MI (United States). Dept. of Geography and Geology)

1994-04-01

7

Hydrogeologic characterization of Illinois wetlands  

SciTech Connect

The Illinois State Geological Survey (ISGS), under contract from the Illinois Department of Transportation (IDOT), is evaluating a series of selected wetlands and sites proposed for wetland construction and/or restoration. The program is associated with wetland mitigation for unavoidable effects of state highway construction. The goal of this ongoing program is: (1) to collect commonly lacking geologic, geomorphic, hydrologic, and geochemical data from various wetland sites; and (2) to create a database of this information for use by government agencies and the private sector. Some of the potential uses of this database include: (1) determination of history, role, and possible life cycle of various wetland types allowing more effective design criteria; (2) functional comparison of constructed or restored wetlands versus natural wetlands; (3) testing of wetland hypotheses and delineation techniques under a variety of known hydrogeologic conditions in Illinois; (4) hydrogeologic assessment of potential mitigation sites against a suite of known sites; and (5) determination of data and collection methods appropriate for hydrogeologic wetland studies. A series of tasks is required to complete each study. Historical information is collected from ISGS records, including data regarding topography, soils, sediments, bedrock, and local well records. A field-testing plan is prepared, which includes goals of the study, methods, research potential, and potential results. An initial report is prepared after geologic and geochemical characterization and the installation of needed ground water monitoring wells and surface water gauges. After one year of water-level monitoring, a final report is prepared regarding the present conditions of a site. Further monitoring may be required to determine the performance at constructed and/or restored sites.

Miner, J.J.; Miller, M.V.; Rorick, N.L.; Fucciolo, C.S. (Illinois State Geological Survey, Champaign, IL (United States))

1994-04-01

8

Hydrogeology of Webb County, Texas  

USGS Publications Warehouse

Introduction: Webb County, in semiarid South Texas on the U.S.-Mexico border, is a region confronted by increasing stresses on natural resources. Laredo (fig. 1), the largest city in Webb County (population 193,000 in 2000), was one of the 10 fastest-growing metropolitan areas in the country during 1990-2000 (Perry and Mackun, 2001). Commercial and industrial activities have expanded throughout the region to support the maquiladora industry (manufacturing plants in Mexico) along the border and other growth as a result of the passage of the North American Free Trade Agreement. The Rio Grande currently (2002) is the primary source of public water supply for Laredo and other cities along the border in Webb County (fig. 1). Other cities, such as Bruni and Mirando City in the southeastern part of the county, rely on ground-water supplies to meet municipal demands. Increased water demand associated with development and population growth in the region has increased the need for the City of Laredo and Webb County to evaluate alternative water sources to meet future demand. Possible options include (1) supplementing the surface-water supply with ground water, and (2) applying artificial storage and recovery (ASR) technology to recharge local aquifers. These options raise issues regarding the hydraulic capability of the aquifers to store economically substantial quantities of water, current or potential uses of the resource, and possible effects on the quality of water resulting from mixing ground water with alternative source waters. To address some of these issues, the U.S. Geological Survey (USGS), in cooperation with the City of Laredo, began a study in 1996 to assess the ground-water resources of Webb County. A hydrogeologic study was conducted to review and analyze available information on the hydrogeologic units (aquifers and confining units) in Webb County, to locate available wells in the region with water-level and water-quality information from the aquifers, and to analyze the hydraulic properties of the aquifers. The purpose of this report is to document the findings of the study. The information is organized by hydrogeologic unit and presented on this and six other sheets.

Lambert, Rebecca B.

2004-01-01

9

Instrumentation for the Hydrogeological Investigation Programme.  

National Technical Information Service (NTIS)

The groundwater measurements during the operation stage are mainly included in an automatic data acquisition system, designed for the thermal investigations of the water in the rock cavern. For the hydrogeological investigations, eight boreholes were equi...

B. Fogdestam L. Saernblad T. Olsson

1984-01-01

10

CNWRA Regional Hydrogeology Geographic Information System Database.  

National Technical Information Service (NTIS)

The Geographic Information System (GIS) database for the Research Project on Regional Hydrogeologic Processes of the Death Valley Region was developed to facilitate the evaluation of existing conceptual models and the construction of alternative conceptua...

G. Wittmeyer R. Klar G. Rice W. Murphy

1995-01-01

11

Teaching hydrogeology: a review of current practice  

NASA Astrophysics Data System (ADS)

Hydrogeology is now taught in a broad spectrum of departments and institutions to students with diverse backgrounds. Successful instruction in hydrogeology thus requires a variety of pedagogical approaches depending on desired learning outcomes and the background of students. We review the pedagogical literature in hydrogeology to highlight recent advances and analyze a 2005 survey among 68 hydrogeology instructors. The literature and survey results suggest there are only ~ 15 topics that are considered crucial by most hydrogeologists and > 100 other topics that are considered crucial by some hydrogeologists. The crucial topics focus on properties of aquifers and fundamentals of groundwater flow, and should likely be part of all undergraduate hydrogeology courses. Other topics can supplement and support these crucial topics, depending on desired learning outcomes. Classroom settings continue to provide a venue for emphasizing fundamental knowledge. However, recent pedagogical advances are biased towards field and laboratory instruction with a goal of bolstering experiential learning. Field methods build on the fundamentals taught in the classroom and emphasize the collection of data, data uncertainty, and the development of vocational skills. Laboratory and computer-based exercises similarly build on theory, and offer an opportunity for data analysis and integration. The literature suggests curricula at all levels should ideally balance field, laboratory, and classroom pedagogy into an iterative and integrative whole. An integrated, iterative and balanced approach leads to greater student motivation and advancement of theoretical and vocational knowledge.

Gleeson, T.; Allen, D. M.; Ferguson, G.

2012-07-01

12

SRP baseline hydrogeologic investigation: Aquifer characterization  

SciTech Connect

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.

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

1992-03-31

13

SRP baseline hydrogeologic investigation, Phase 2  

SciTech Connect

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.

Bledsoe, H.W.

1987-11-01

14

SRP Baseline Hydrogeologic Investigation, Phase 3  

SciTech Connect

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.

Bledsoe, H.W.

1988-08-01

15

Hydrogeologic assessment---Figeh Spring, Damascus, Syria  

Microsoft Academic Search

Hydrogeological studies at Figeh Springs were directed to determine groundwater flow paths, research, storage and discharge units, and the maximum reliable yield. The project was designed to provide information upon which to base pumpage to augment low-season flows from the spring which is the major water supply for the city of Damascus, Syria. As a basis for conclusions and recommendations,

P. E. Lamoreaux; Travis H. Hughes; Bashir A. Memon; Neal Lineback

1989-01-01

16

Hydrogeologic assessment—Figeh Spring, Damascus, Syria  

Microsoft Academic Search

Hydrogeological studies at Figeh Springs were directed to determine groundwater flow paths, research, storage and discharge units, and the maximum reliable yield. The project was designed to provide information upon which to base pumpage to augment low-season flows from the spring which is the major water supply for the city of Damascus, Syria.

P. E. Lamoreaux; Travis H. Hughes; Bashir A. Memon; Neal Lineback

1989-01-01

17

The ancient Chinese notes on hydrogeology  

NASA Astrophysics Data System (ADS)

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.

Zhou, Yu; Zwahlen, François; Wang, Yanxin

2011-08-01

18

Current research in urban hydrogeology - A review  

NASA Astrophysics Data System (ADS)

Urban groundwater is a heritage at risk because urban land use practises puts enormous and highly complex pressure on this resource. In this article, we review urban groundwater studies in the context of urban water management, discuss advances in hydrogeological investigation, monitoring and modelling techniques for urban areas and highlight the challenges. We present how techniques on contaminant concentration measurements, water balancing and contaminant load estimation were applied and further developed for the special requirements in urban settings. To fully understand and quantify the complex urban water systems, we need to refine these methods and combine them with sophisticated modelling approaches. Only then we will be able to sustainably manage our water resources in and around our urban areas especially in light of growing cities and global climatic change. We believe that over the next few years much more effort will be devoted to research in urban hydrogeology.

Schirmer, Mario; Leschik, Sebastian; Musolff, Andreas

2013-01-01

19

GEO-SCI 587: Introduction to Hydrogeology  

NSDL National Science Digital Library

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.

Boutt, David; Amherst, University O.

20

GIS-based hydrogeological databases and groundwater modelling  

Microsoft Academic Search

.   Reliability and validity of groundwater analysis strongly depend on the availability of large volumes of high-quality data.\\u000a Putting all data into a coherent and logical structure supported by a computing environment helps ensure validity and availability\\u000a and provides a powerful tool for hydrogeological studies. A hydrogeological geographic information system (GIS) database that\\u000a offers facilities for groundwater-vulnerability analysis and hydrogeological

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

2001-01-01

21

Marine hydrogeology: recent accomplishments and future opportunities  

NASA Astrophysics Data System (ADS)

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.

Fisher, A. T.

2005-03-01

22

SRS baseline hydrogeologic investigation: Summary report  

SciTech Connect

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.

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

23

Case studies in organic contaminant hydrogeology  

NASA Astrophysics Data System (ADS)

The effective management of domestic solid waste and hazardous, toxic, and radioactive waste is a major problem in the area of environmental geology and water sciences over the world. This series of case studies of organic contaminants from both solid and hazardous waste disposal facilities provides examples of these problems. The facilities were investigated to determine risks and liabilities before acquisition, to determine the site hydrogeologic conditions for design of appropriate groundwater monitoring plans, and/or to determine the potential for groundwater contamination. The results of these studies and investigations by Waste Management Inc. (WMI) and its consultants have shown certain relationships in the distribution of organic pollutants to the different geologic and hydrogeologic charac teristics of each facility. In each of the case studies, all 129 priority pollutants were analyzed in private wells and/or monitoring wells at the request of regulatory agencies. The 31 volatile organic compounds (VOCs) of the priority pollutant list were the majority of the organic compounds detected and these data are evaluated in each case study. The case studies are on disposal facilities located in glacial tills, carbonaceous weathered clay soils, weathered shale, limestone bedrock, dolomite bedrock, and alluvial and sedimentary deposits. A brief discussion of groundwater quality impacts and remedial measures also is included.

Baker, John A.

1989-07-01

24

Analysis of hydrogeological structure uncertainty by estimation of hydrogeological acceptance probability of geostatistical models  

NASA Astrophysics Data System (ADS)

The following describes a proposed approach to account for the equifinality of solutions that result from comparing observations to flow simulations when using realizations of geostatistical models. We introduce hydrogeological acceptance probability to estimate the propensity of a geostatistical model to produce acceptable realizations with respect to the consistency of their simulations with observations. The estimation of hydrogeological acceptance probability is equivalent to the calculation of the sample mean of a Bernoulli distribution. This allows the estimation of the acceptance probability to be preemptively terminated based on the current estimate and subject to the desired confidence level and interval length. We propose a composite uncertainty analysis of the hydrogeological heterogeneity utilizing acceptable realizations from multiple geostatistical models collected during the estimation of their acceptance probability. In the case of a non-fuzzy definition of realization acceptance, this produces a facies probability map. If the definition of realization acceptance is imprecise, the analysis yields upper and lower bounds on the facies probability map in the form of facies plausibility and belief maps, respectively. These maps can provide indications of the information content of the data and provide guidance for the collection of additional data.

Harp, Dylan R.; Vesselinov, Velimir V.

2012-02-01

25

Hydrogeology and Mineral Weathering Reactions in Watersheds of Central Massachusetts.  

National Technical Information Service (NTIS)

A study of two watersheds draining into Quabbin Reservoir (E. Branch Swift River and Cadwell Creek) reveal the prime importance of hydrogeology in controlling acid neutralization potential of watershed systems. In the East Branch Swift River, Carter Brook...

R. F. Yuretich P. J. Stekl S. J. Pohanka

1986-01-01

26

2101-M Pond hydrogeologic characterization report  

SciTech Connect

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.

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

1990-09-01

27

Hydrogeological criteria for final storage quality  

NASA Astrophysics Data System (ADS)

Disposal of hazardous non-radioactive wastes is a major problem because of our incomplete understanding of subsurface processes. We are forced to simplify with models and thus to overlook some of the natural defects in real storage sites. The aim of this paper is to provide a conceptual framework and to discuss some examples of previously overlooked processes leading to leakage in storage sites. In the late seventies the hydrogeologic methodology and the governmental regulatory guidelines were insufficient to prevent contamination of groundwater and atmospheric pollution. Frequently, engineers dealt with the bulk properties of rocks and grossly underestimated the influence of the 3-D flow system due to the variable interconnections between permeable zones and the heterogeneous mineralogical and sedimentological character of the media under consideration. Analysis of different geological environments shows that under natural conditions we mostly have to deal with associations of different rock-types belonging to the same genetic system. Predicting the lateral extent of a particular rock-type -e.g. of very low permeability- is very difficult and essentially depends on our understanding of the depositional environment or of the tectonic and igneous processes.

Huggenberger, Peter

28

Flowing with the changing needs of hydrogeology instruction  

NASA Astrophysics Data System (ADS)

Hydrogeology is now taught in a broad spectrum of departments and institutions to students with diverse backgrounds. Successful instruction in hydrogeology thus requires a variety of pedagogical approaches depending on desired learning outcomes and the diverse background of students. We review the pedagogical literature in hydrogeology to highlight recent advances and analyze a 2005 survey of 68 hydrogeology instructors. The literature and survey results suggest there are ~15 topics that are considered crucial by most hydrogeologists and >100 other topics that are considered crucial by some hydrogeologists. The crucial topics focus on properties of aquifers and fundamentals of groundwater flow, and should likely be part of all undergraduate hydrogeology courses. Other topics can supplement and support these crucial topics, depending on desired learning outcomes. Classroom settings continue to provide a venue for emphasizing fundamental knowledge. However, recent pedagogical advances are biased towards field and laboratory instruction with a goal of bolstering experiential learning. Field methods build on the fundamentals taught in the classroom and emphasize the collection of data, data uncertainty, and the development of vocational skills. Laboratory and computer-based exercises similarly build on theory, and offer an opportunity for data analysis and integration. The literature suggests curricula at all levels should ideally balance field, laboratory, and classroom pedagogy into an iterative and integrative whole. An integrated approach leads to greater student motivation and advancement of theoretical and vocational knowledge.

Gleeson, T.; Allen, D. M.; Ferguson, G.

2012-01-01

29

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...

30

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...

31

Implication of fractal dimension in hydrogeology and rock mechanics. Version 1.1.  

National Technical Information Service (NTIS)

Since much of geology and hydrogeology is controlled by the geometry of geologic features such as faults, fractures and stratigraphy, many researchers have proposed the use of fractal dimension as an index for comparing hydrogeologic environments. This re...

W. Dershowitz K. Redus P. Wallmann P. LaPointe C. L. Axelsson

1992-01-01

32

Interdisciplinary hydrogeologic site characterization at the Nevada Test Site  

SciTech Connect

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

Hawkins, W.L. [Los Alamos National Lab., NM (United States); Wagoner, J.L. [Lawrence Livermore National Lab., CA (United States); Drellack, S.L. [Raytheon Services Nevada, Mercury, NV (United States)

1992-06-01

33

Interdisciplinary hydrogeologic site characterization at the Nevada Test Site  

SciTech Connect

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

Hawkins, W.L. (Los Alamos National Lab., NM (United States)); Wagoner, J.L. (Lawrence Livermore National Lab., CA (United States)); Drellack, S.L. (Raytheon Services Nevada, Mercury, NV (United States))

1992-01-01

34

Hydrogeological characterization of sedimentary rocks with numerical inversion using steady-state hydraulic head data  

Microsoft Academic Search

In the hydrogeological characterization of sedimentary rocks, hydraulic properties of fault and cap rock structures are important factors. Although, the certainty of a hydrogeological model depends on the amount of geological or hydrogeological data, mainly obtained from boreholes, it is indispensable to make a preliminary model from a small amount of data obtained in the early stage of field investigation,

K. Ito; K. Karasaki

2003-01-01

35

The French network of hydrogeological sites H+  

NASA Astrophysics Data System (ADS)

For groundwater issues (potential leakages in waste repository, aquifer management "), the development of modeling techniques is far ahead of the actual knowledge of aquifers. This raises two fundamental issues: 1) which and how much data are necessary to make predictions accurate enough for aquifer management issues; 2) which models remain relevant to describe the heterogeneity and complexity of geological systems. The French observatory H+ was created in 2002 with the twofold motivation of acquiring a large database for validating models of heterogeneous aquifers, and of surveying groundwater quality evolution in the context of environmental changes. H+ is a network of 4 sites (Ploemeur, Brittany, France; HES Poitiers, France; Cadarache, France; Campos, Mallorca, Spain) with different geological, climatic, and economic contexts. All of them are characterized by a highly heterogeneous structure (fractured crystalline basement for Ploemeur, karstified and fractured limestone for Poitiers, Cadarache and Mallorca), which is far to be taken into account by basic models. Ploemeur is exploited as a tap-water plant for a medium-size coastal city (15,000 inhabitants) for 20 years. Each site is developed for long term investigation and monitoring. They involves a dense network of boreholes, detailed geological and geophysical surveys, periodic campaigns and/or permanent measurements of groundwater flow, water chemistry, geophysical signals (including ground motions), climatic parameter, etc. Several large-scale flow experiments are scheduled per year to investigate the aquifer structure with combined geophysical, hydrogeological, and geochemical instruments. All this information is recorded in a database that has been developed to improve the sustainability and quality of data, and to be used as a collaborative tool for both site researchers and modelers. This project lasts now for 5 years. It is a short time to collect the amount of information necessary to apprehend the complexity of aquifers; but it is already enough to obtain a few important scientific results about the very nature of the flow heterogeneity, the origin and residence time of water elements, the kinetic of geochemical processes, etc. We have also developed new methods to investigate aquifers (in-situ flow measurements, flow experiment designs, groundwater dating, versatile in-situ probes, etc.). This experience aiming at building up long term knowledge appears extremely useful to address critical issues related to groundwater aquifers: the structure and occurrence of productive aquifer in crystalline basement, the assessment of aquifer protection area in the context of highly heterogeneous flow, the biochemical reactivity processes, the long term evolution of both water quantity and quality in the context of significant environmental changes, for instance.

Davy, P.; Le Borgne, T.; Bour, O.; Gautier, S.; Porel, G.; Bodin, J.; de Dreuzy, J.; Pezard, P.

2008-12-01

36

Hydrogeology of the Azores volcanic archipelago (Portugal)  

NASA Astrophysics Data System (ADS)

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.

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

2009-04-01

37

Hydrogeology of the Mogollon Highlands, central Arizona  

USGS Publications Warehouse

The Mogollon Highlands, 4,855 square miles of rugged, mountainous terrain at the southern edge of the Colorado Plateau in central Arizona, is characterized by a bedrock-dominated hydrologic system that results in an incompletely integrated regional ground-water system, flashy streamflow, and various local water-bearing zones that are sensitive to drought. Increased demand on the water resources of the area as a result of recreational activities and population growth have made necessary an increased understanding of the hydrogeology of the region. The U.S. Geological Survey conducted a study of the geology and hydrology of the region in cooperation with the Arizona Department of Water Resources under the auspices of the Arizona Rural Watershed Initiative, a program launched in 1998 to assist rural areas in dealing with water-resources issues. The study involved the analysis of geologic maps, surface-water and ground-water flow, and water and rock chemical data and spatial relationships to characterize the hydrogeologic framework. The study area includes the southwestern corner of the Colorado Plateau and the Mogollon Rim, which is the eroded edge of the plateau. A 3,000- to 4,000-foot sequence of early to late Paleozoic sedimentary rocks forms the generally south-facing scarp of the Mogollon Rim. The area adjacent to the edge of the Mogollon Rim is an erosional landscape of rolling, step-like terrain exposing Proterozoic metamorphic and granitic rocks. Farther south, the Sierra Ancha and Mazatzal Mountain ranges, which are composed of various Proterozoic rocks, flank an alluvial basin filled with late Cenozoic sediments and volcanic flows. Eight streams with perennial to intermittent to ephemeral flow drain upland regions of the Mogollon Rim and flow into the Salt River on the southern boundary or the Verde River on the western boundary. Ground-water flow paths generally are controlled by large-scale fracture systems or by karst features in carbonate rocks. Stream channels are also largely controlled by structural features, such as regional joint or fault systems. Precipitation, which shows considerable variability in amount and intensity, recharges the ground-water system along the crest of the Mogollon Rim and to a lesser extent along the crests and flanks of the rim and the Mazatzal Mountains and Sierra Ancha. Flashy runoff in the mainly bedrock stream channels is typical. Springs are distributed throughout the region, typically discharging at or above the contact of variably permeable formations along the face of the Mogollon Rim with a scattering of low-discharge springs in the Proterozoic rocks below the rim. The surface of the Colorado Plateau is the primary recharge area for the C aquifer in which ground-water flows north toward the Little Colorado River and south toward the Mogollon Highlands. Within the study area, flow from the C aquifer primarily discharges from large, stable springs in the upper East Verde River, Tonto Creek, and Canyon Creek Basins along the top of the Mogollon Rim and to the west as base flow in West Clear Creek. On the basis of chemical evidence and the distribution and flow characteristics of springs and perennial streams, the C aquifer is also the source of water for the limestone aquifer that discharges from carbonate rocks near the base of the Mogollon Rim. Vertical flow from the C aquifer, the base of which is in the Schnebly Hill Formation, recharges the limestone aquifer that discharges mainly at Fossil Springs in the western part of the study area and as base flow in Cibecue Creek on the eastern edge of the study area. Local, generally shallow aquifers of variable productivity occur in plateau and mesa-capping basalts in the sedimentary rocks of the Schnebly Hill and Supai Formations, in fractured zones of the Proterozoic Payson granite, and in the alluvium of the lower Tonto Creek Basin. Where time series data exist, such water-bearing zones are shown to be sensitive to short-

Parker, John T. C.; Steinkampf, William C.; Flynn, Marilyn E.

2005-01-01

38

Hydrogeologic impacts in the Estonian oil shale deposit  

Microsoft Academic Search

The article describes the hydrogeological problems related to water influx to the mine and water sulphate content association with underground oil shale mining in an environmentally sensitive area of Estonia. The water balance method was used to calculate the ratio of mine water outflow\\/inflow. Water balance calculations are needed for estimating the groundwater transversal flow into closed mines. Before oil

Katrin Erg; Jyri-Rivaldo Pastarus

2008-01-01

39

Geomorphology and hydrogeology of the Edwards Plateau karst, central Texas  

Microsoft Academic Search

The Edwards Plateau is one of the largest continuous karst regions of the United States; yet, its geomorphic evolution has previously received little systematic study. The overall objectives of this investigation are to: (1) describe the physical characteristics of karst features, (2) determine which geomorphic and hydrogeologic controls and processes have governed their development, and (3) relate genesis of karst

E. H. Kastning Jr.

1983-01-01

40

Expanding the hydrogeological base in mining EIA studies  

Microsoft Academic Search

Conducive economic policies have led to a vibrant minerals and mining sector in Ghana, with the establishment of 12 new large-scale gold mines since 1988. The Environmental Protection Agency (EPA) has been strengthened and a robust monitoring regime is in place to prevent abuse of the environment. Insufficient attention has been paid, however, to the necessary hydrogeological detail of statutory

Jerry S Kuma; Paul L Younger; Rob J Bowell

2002-01-01

41

Hydrogeological concepts in the United States: a historical perspective.  

USGS Publications Warehouse

Reviews the development of hydrogeological concepts in the USA from 1879 to 1987, from early qualitative reconnaissance investigations to modern qualitative and multi-disciplinary studies involving predictive analytical techniques and a consideration of management practices. The authors present a sampling of historical milestone papers in US hydrology in the form of an annotated bibliography.-Authors

Moore, J. E.; Hanshaw, B. B.

1987-01-01

42

Combined Estimation of Hydrogeologic Conceptual Model and Parameter Uncertainty  

Microsoft Academic Search

The objective of the research described in this report is the development and application of a methodology for comprehensively assessing the hydrogeologic uncertainties involved in dose assessment, including uncertainties associated with conceptual models, parameters, and scenarios. This report describes and applies a statistical method to quantitatively estimate the combined uncertainty in model predictions arising from conceptual model and parameter uncertainties.

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

2004-01-01

43

Hydrogeologic controls on petroleum accumulation in the Great Basin  

SciTech Connect

Great Basin hydrocarbon accumulations and groundwater flow are intrinsically related. Hydrocarbon migration is controlled by forces generated or transmitted by water. Groundwater entrained hydrocarbons converge upon and are trapped in fluid potential minima; water is identified as an important reservoir drive mechanism in most Great Basin oil fields. Numerous hydrogeologic indicators of hydrocarbon accumulation (surface hydrocarbon seepage, chemically reducing near-surface conditions, electromagnetic anomalies, positive geothermal anomalies, etc.) occur in the region`s oil producing valleys. The addition of hydrogeologic methodology to conventional exploration practices should reduce exploration risk the region. In an attempt to explain the distribution of oil fields and hydrogeologic hydrocarbon indicators, a two layer hydrogeologic model of the eastern Great Basin was developed. A deeper, regional flow system, coincident with a thick sequence of Paleozoic carbonate rock, underlies eastern Nevada and western Utah. Widespread distribution and high transmissivity fosters interbasin flow within the regional system. Superimposed on the regional system is a relatively shallow and localized groundwater flow system; flow in this system is confined to valley-fill deposits and adjoining mountain ranges. Petroleum accumulation incidence increases towards areas of regional fluid convergence, and all Nevada oil fields were found to be located within the discharge areas of deep, regional flow systems. Vertical seals develop where hot, relatively mineral laden waters of the regional flow system mix with the cooler, fresh waters of the local flow system.

Grabb, R.F. [Consulting Geologist, Billings, MT (United States)

1995-06-01

44

Hydrogeological changes in coastal aquifers due to sea level rise  

Microsoft Academic Search

Global warming and climatic changes can lead to sea level rise (SLR) of dozens of cms over up-coming decades, along with groundwater permanent reserve losses (PRL). This study focuses on understanding the processes and estimating groundwater losses. A case study for such phenomena is Israel's Coastal aquifer. PRL estimation methodology is based upon a simple hydrogeological conceptual model. The results

A. Melloul; M. Collin

2006-01-01

45

Hydrogeological deformation from GPS time series in Northern Morocco.  

NASA Astrophysics Data System (ADS)

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.

Moreau, F.; Dauteuil, O.

2012-04-01

46

HYDROGEOLOGIC CHARACTERIZATION OF THE U-3bl COLLAPSE ZONE  

SciTech Connect

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.

Bechtel Nevada and National Security Technologies, LLC

2006-09-01

47

The hydrogeologic-geochemical model of Cerro Prieto revisited  

SciTech Connect

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.

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

1989-01-01

48

Hydrogeologic model of the Ahuachapan geothermal field, El Salvador  

SciTech Connect

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.

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

49

Hydrogeological studies on the Tarkwa gold mining district, Ghana  

Microsoft Academic Search

The physical hydrogeology of the Tarkwa area has been evaluated with a view to improving the understanding of its groundwater\\u000a characteristics. It has been inferred that aquifers in the Tarkwa area possess dual and variable porosity and heterogeneous\\u000a permeability with predominantly limited storage properties. Both soil infiltration and pumping tests have shown that the Banket\\u000a Series has the best hydraulic

Jerry S. Kuma

2007-01-01

50

Stochastic characterization of hydrogeological properties using geophysical data  

NASA Astrophysics Data System (ADS)

Near-surface investigations often require characterization of hydraulic parameters. Conventional sampling or borehole techniques for estimating these parameters are costly, time-consuming, and invasive. The difficulty of collecting representative and sufficient hydraulic property measurements using conventional sampling techniques, the large spatial variability of hydraulic properties in natural geologic systems over a wide range of scales, and the dependence on the measurement support scale renders measurement of hydraulic properties and estimation of spatial correlation parameters difficult. The purpose of this study is to explore the use of joint geophysical-hydrogeological data for estimation of hydrological parameters and their spatial correlation structure. A review of geophysical techniques available for near-surface characterization is briefly presented, followed by a summary of several case studies where tomographic geophysical data were used within a deterministic framework to estimate hydrological properties. For situations where there is non-uniqueness associated with the hydrogeological estimates inferred from the geophysical data, where the data are scarce or the resolution of the data are too low to capture small-scale variability, or where it is necessary to quantify the uncertainty associated with the estimates, stochastic estimation techniques are appropriate. The first stochastic methodology presented in this study focuses on producing high resolution point estimates of hydrogeological properties using densely sampled ground penetrating radar data and limited borehole data. The second stochastic methodology presented involves log-permeability estimation using the theory of Bayesian conditioning when multiple co-located, high-resolution geophysical data fields are available for interpretation. Although these studies suggest that high resolution geophysical data are useful for obtaining these hydrogeological point value estimates, in practice high resolution geophysical data such as tomographic seismic or radar tomographic profiles often sample only a small portion of the aquifer under investigation. Stochastic simulation techniques are commonly used to generate hydrogeological values for the rest of the study volume; these techniques require as input information about the parameter's spatial covariance structure. The third and last stochastic methodology presented focuses on using high-resolution radar or seismic data together with limited borehole data to infer the log-permeability spatial correlation structure. These combined studies suggest that collection of a few tomographic profiles and interpretation of these profiles together with limited wellbore data can yield both hydraulic point value estimates and correlation structure information that are otherwise obtainable only from extensive hydrological sampling.

Hubbard, Susan Sharpless

51

Application of three dimensional geological models to hydrogeology  

NASA Astrophysics Data System (ADS)

Recently, three dimensional (3D) numerical simulation of subsurface structure has become a common engineering geological tool to investigate a variety of geological settings. Besides, hydrogeology always tightly combines with geological structures. For these reasons, coupling 3D geological models with hydrogeology will not only improve understanding of subsurface conditions, but also provide a common stratigraphic framework for hydrogeological applications. The reliability of 3D geological models largely depends on the quality and quantity of data. Normally, before 3D geological models are constructed in the software package, the initial data (borehole descriptions, geological maps, geological cross sections, outcrop data, geo-electrical survey, digital elevation model, etc.) are acquired from archive as much as possible and standardized in a single table. To ensure the precision of models, new drilling data should be gathered from local authorities such as Geological Survey in time. Some experimental data are necessary to be kept at the initial moment to create a subset for verification of the models. In particular, the resulting models will be used for hydrogeological applications. So, more parameters should be collected to construct the 3D property models. Properties contain porosities of soil, bearing capacity, compressibility and particular geological phenomenon such as the regional aquifers, aquitard and faults. During the processing of model construction, the minimum element of the models is grid, which can be converted to some finite elements software. Further studies of these models to hydrogeological application involve: integrating faulted horizons of the 3D geological model into the groundwater modeling software package and simulating the groundwater flow within the main relevant aquifers using a finite elements approach; simulating distribution and calculating volume of groundwater in particular area; providing 3D parameters for vulnerability maps of groundwater, and comparing the results with the vulnerability maps constructed by 2D parameters; establishing the information system as a complement for long-term land use planning of cities; and helping to control widespread land subsidence risks in cities where the water table is lower by overexploitation of groundwater.

Dong, M.; Neukum, C.; Azzam, R.

2009-04-01

52

Hydrogeology of the Upper Floridan Aquifer in the Vicinity of the Marine Corps Logistics Base Near Albany, Georgia.  

National Technical Information Service (NTIS)

This report describes the results of an investigation of the hydrogeology of the Upper Floridan aquifer in the vicinity of the Marine Corps Logistics Base (MCLB), located southeast of and adjacent to Albany, GA. Specifically, the hydrogeologic framework i...

K. B. McSwain

1999-01-01

53

Warning system for hydrogeological hazards in Campania (Southern Italy)  

NASA Astrophysics Data System (ADS)

Campania is the Italian region with the highest population density (419 inhabitants/km2). Almost 20% of its territory (13669 km2) is affected by significant hydrogeological hazards, with related loss scenarios in almost 12% of it. The most critical hydrogeological hazard scenarios are those triggered by extreme rainfall events with duration ranging from a few tens of minutes up 72 hours: flood loss scenarios are expected in catchments with spatial extent from a few Km2 up to 5000 km2; shallow landslides and mudflows are also triggered by rainfall events within a broad range of time scales. This study presents a warning system for hydrogeological hazards, which has been operating in Campania since 2005, designed for mitigating losses due to extreme rainfall events. The warning system is structured into two stages: the meteorological forecasting stage and the hydrological monitoring stage. In the first stage, after evaluating rainfall forecasts provided by numerical weather prediction models (with a forecasting time up to 48 hours), warning messages are issued to the local municipalities grouped in 8 warning zones. Critical rainfall events are identified by three different alert levels, according to their forecasted spatial and temporal extents, each corresponding to a category of expected hazard scenarios at regional level. During the second stage, the dynamic evolution of the hydrological events is monitored by a real-time network of river stage and rain gauges, which are employed to compute one or more precursors for each loss scenario. Loss scenarios have been classified according to the temporal and spatial scales of the corresponding precursors, in order to deal with the difficulties related to the occurrence of significantly different hazard scenarios during the same rainfall event. Three threshold values have been identified for each precursor, corresponding to given hazard and alert levels. As a precursor exceeds a threshold value, warning messages are issued to local municipalities whose territory might be affected by the corresponding loss scenario.

Biafore, Mauro; Cristiano, Luigi; Gentile, Salvatore; Gentilella, Matteo; Giannattasio, Maurizio; Napoli, Francesca

2010-05-01

54

Hydrogeologic Modeling of Submarine Groundwater Discharge: Comparison to Other Quantitative Methods  

Microsoft Academic Search

Submarine groundwater discharge (SGD) is approached differently by terrestrial hydrogeologists and marine scientists, including whether to incorporate recirculated seawater with freshwater in the definition. This paper focuses on the major hydrogeologic modeling\\/calculational methods, what component of SGD they quantify and on what scale. It then compares the modeling methods to direct measurement and geochemical techniques used by marine scientists. Hydrogeologic

June A. Oberdorfer

2003-01-01

55

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

Microsoft Academic Search

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

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

2003-01-01

56

Hydrogeologic map of the Death Valley region, Nevada, and California, developed using GIS techniques.  

National Technical Information Service (NTIS)

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 bord...

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

1997-01-01

57

Hydrogeologic unit flow characterization using transition probability geostatistics.  

PubMed

This paper describes a technique for applying the transition probability geostatistics method for stochastic simulation to a MODFLOW model. Transition probability geostatistics has some advantages over traditional indicator kriging methods including a simpler and more intuitive framework for interpreting geologic relationships and the ability to simulate juxtapositional tendencies such as fining upward sequences. The indicator arrays generated by the transition probability simulation are converted to layer elevation and thickness arrays for use with the new Hydrogeologic Unit Flow package in MODFLOW 2000. This makes it possible to preserve complex heterogeneity while using reasonably sized grids and/or grids with nonuniform cell thicknesses. PMID:15819951

Jones, Norman L; Walker, Justin R; Carle, Steven F

58

3D Hydrogeological Modeling of Impact from Tunneling  

NASA Astrophysics Data System (ADS)

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

Kohl, T.; Megel, T.

2005-12-01

59

Martian hydrogeology sustained by thermally insulating gas and salt hydrates  

NASA Astrophysics Data System (ADS)

Numerical simulations and geologic studies suggest that high thermal anomalies beneath, within, and above thermally insulating layers of buried hydrated salts and gas hydrates could have triggered and sustained hydrologic processes on Mars, producing or modifying chaotic terrains, debris flows, gullies, and ice-creep features. These simulations and geologic examples suggest that thick hydrate deposits may sustain such geothermal anomalies, shallow ground-water tables, and hydrogeologic activity for eons. The proposed mechanism may operate and be self-reinforcing even in today's cold Martian climate without elevated heat flux.

Kargel, Jeffrey S.; Furfaro, Roberto; Prieto-Ballesteros, Olga; Rodriguez, J. Alexis P.; Montgomery, David R.; Gillespie, Alan R.; Marion, Giles M.; Wood, Stephen E.

2007-11-01

60

Evaluation of hydrogeological conditions based on modelling: a case study in the Kampinos National Park region, central Poland  

Microsoft Academic Search

Hydrogeological modelling of the Kampinos National Park (KNP) region has been carried out. The KNP comprises a hydrogeological unit of valley relatively simple structure, and has been investigated empirically and theoretically since the 1970's. Results of numerical modelling given here provide a quantitative evaluation of hydrogeological parameters, recharging infiltration, river drainage and evapotranspiration processes (groundwater evaporation), water balance and the

Ewa KROGULEC

61

Hydrogeology and groundwater ecology: Does each inform the other?  

NASA Astrophysics Data System (ADS)

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.

Humphreys, W. F.

2009-02-01

62

The use of multicomponent statistical analysis in hydrogeological environmental research.  

PubMed

The present article examines the possibilities of investigating NO(3)(-) spread in aquifers by applying multicomponent statistical methods (factor, cluster and discriminant analysis) on hydrogeological, hydrochemical, and environmental parameters. A 4-R-Mode factor model determined from the analysis showed its useful role in investigating hydrogeological parameters affecting NO(3)(-) concentration, such as its dilution by upcoming groundwater of the recharge areas. The relationship between NO(3)(-) concentration and agricultural activities can be determined sufficiently by the first factor which relies on NO(3)(-) and SO(4)(2-) of the same origin-that of agricultural fertilizers. The other three factors of R-Mode analysis are not connected directly to the NO(3)(-) problem. They do however, by extracting the role of the unsaturated zone, show an interesting relationship between organic matter content, thickness and saturated hydraulic conductivity. The application of Hirerarchical Cluster Analysis, based on all possible combinations of classification method, showed two main groups of samples. The first group comprises samples from the edges and the second from the central part of the study area. By the application of Discriminant Analysis it was shown that NO(3)(-) and SO(4)(2-) ions are the most significant variables in the discriminant function. Therefore, the first group is considered to comprise all samples from areas not influenced by fertilizers lying on the edges of contaminating activities such as crop cultivation, while the second comprises all the other samples. PMID:15026241

Lambrakis, Nicolaos; Antonakos, Andreas; Panagopoulos, George

2004-04-01

63

The application of seismic techniques to hydrogeological investigations  

NASA Astrophysics Data System (ADS)

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

Jarvis, Kevin Donald Gibson

64

Incorporating Fuzzy Systems Modeling and Possibility Theory in Hydrogeological Uncertainty Analysis  

NASA Astrophysics Data System (ADS)

Hydrogeological predictions are subject to numerous uncertainties, including the development of conceptual, mathematical, and numerical models, as well as determination of their parameters. Stochastic simulations of hydrogeological systems and the associated uncertainty analysis are usually based on the assumption that the data characterizing spatial and temporal variations of hydrogeological processes are random, and the output uncertainty is quantified using a probability distribution. However, hydrogeological systems are often characterized by imprecise, vague, inconsistent, incomplete or subjective information. One of the modern approaches to modeling and uncertainty quantification of such systems is based on using a combination of statistical and fuzzy-logic uncertainty analyses. The aims of this presentation are to: (1) present evidence of fuzziness in developing conceptual hydrogeological models, and (2) give examples of the integration of the statistical and fuzzy-logic analyses in modeling and assessing both aleatoric uncertainties (e.g., caused by vagueness in assessing the subsurface system heterogeneities of fractured-porous media) and epistemic uncertainties (e.g., caused by the selection of different simulation models) involved in hydrogeological modeling. The author will discuss several case studies illustrating the application of fuzzy modeling for assessing the water balance and water travel time in unsaturated-saturated media. These examples will include the evaluation of associated uncertainties using the main concepts of possibility theory, a comparison between the uncertainty evaluation using probabilistic and possibility theories, and a transformation of the probabilities into possibilities distributions (and vice versa) for modeling hydrogeological processes.

Faybishenko, B.

2008-12-01

65

Hydrogeologic Unit Flow Characterization Using Transition Probability Geostatistics  

SciTech Connect

This paper describes a technique for applying the transition probability geostatistics method for stochastic simulation to a MODFLOW model. Transition probability geostatistics has several advantages over traditional indicator kriging methods including a simpler and more intuitive framework for interpreting geologic relationships and the ability to simulate juxtapositional tendencies such as fining upwards sequences. The indicator arrays generated by the transition probability simulation are converted to layer elevation and thickness arrays for use with the new Hydrogeologic Unit Flow (HUF) package in MODFLOW 2000. This makes it possible to preserve complex heterogeneity while using reasonably sized grids. An application of the technique involving probabilistic capture zone delineation for the Aberjona Aquifer in Woburn, Ma. is included.

Jones, N L; Walker, J R; Carle, S F

2003-11-21

66

Hydrogeology and quality of ground water in Orange County, Florida  

USGS Publications Warehouse

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

Adamski, James C.; German, Edward R.

2004-01-01

67

Unraveling complex hydrogeologic systems using field tracer tests  

NASA Astrophysics Data System (ADS)

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

Dam, William A.; Nicholson, Thomas

68

Hydrogeologic Framework of the New Jersey Coastal Plain  

USGS Publications Warehouse

This report presents the results of a water-resources, oriented subsurface mapping program within the Coastal Plain of New Jersey. The occurrence and configuration of 15 regional hydrogeologic units have been defined, primarily on the basis of an interpretation of borehole geophysical data. The nine aquifers and six confining beds are composed of unconsolidated clay, silt, sand, and gravel and range in age from Cretaceous to Quaternary. Electric and gamma-ray logs from more than 1,000 Coastal Plain wells were examined. Of these, interpretive data for 302 sites were selected, on the basis of logged depth, quality of data, and data distribution, to prepare structure contour and thickness maps for each aquifer and a thickness map for each confining bed. These maps, together with 14 hydrogeologic sections, show the geometry, lateral extent, and vertical and horizontal relationships among the 15 hydrogeologic units. The hydrogeologic maps and sections show that distinct lower, middle, and upper aquifers are present within the Potomac, Raritan-Magothy aquifer system near the Delaware River from Burlington County to Salem County. Although the lower aquifer is recognized only in this area, the middle aquifer extends into the northeastern Coastal Plain of New Jersey, where it is stratigraphically equivalent to the Farrington aquifer. The upper aquifer extends throughout most of the New Jersey Coastal Plain and is stratigraphically equivalent to the Old Bridge aquifer in the northeastern Coastal Plain. The overlying Merchantville-Woodbury confining bed is the most regionally extensive confining bed within the New Jersey Coastal Plain. Its thickness ranges from less than 100 feet near the outcrop to more than 450 feet along the coast. The Englishtown aquifer system acts as a single aquifer throughout most of its subsurface extent, but it contains two water-bearing sands in pars of Monmouth and Ocean Counties. The overlying Marshalltown-Wenonah confining bed is a thin, leaky unit ranging in thickness from approximately 20 to 80 feet. The Wenonah-Mount Laurel aquifer is identified in the subsurface throughout the New Jersey Coastal Plain southeast of its outcrop area. Sediments that overlie the Wenonah-Mount Lauren aquifer and that are subjacent to the major aquifers within the Kirkwood Formation and the Cohansey Sand are described hydrologically as a composite confining bed. These include the Navesink Formation, Red Bank Sand, Tinton Sand, Hornerstown Sand, Vincentown Formation, Manasquan Formation, Shark River Formation, and Piney Point Formation and the basal clay of the Kirkwood Formation.. The Vincentown Formation functions as n aquifer within 3 to 10 miles downdip of its outcrop area. In areas farther downdip the Vincentown Formation functions as a confining bed. The Piney Point aquifer is laterally persistent from the southern New Jersey Coastal Plain northward into parts of Burlington and Ocean Counties. The Atlantic City 800-foot sand of the Kirkwood Formation can be recognized in the subsurface along coastal areas of Cape May, Atlantic, and southern Ocean Counties, but inland only as far west as the extent of the overlying confining bed. In areas west of the extent of the overlying confining bed, the Kirkwood Formation is in hydraulic connection with the overlying Cohansey Sand and younger surficial deposits and functions as an unconfined aquifer.

Zapecza, Otto S.

1989-01-01

69

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

USGS Publications Warehouse

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

Low, Dennis J.; Dugas, Diana L.

1999-01-01

70

Using GA-Ridge regression to select hydro-geological parameters influencing groundwater pollution vulnerability.  

PubMed

For groundwater conservation and management, it is important to accurately assess groundwater pollution vulnerability. This study proposed an integrated model using ridge regression and a genetic algorithm (GA) to effectively select the major hydro-geological parameters influencing groundwater pollution vulnerability in an aquifer. The GA-Ridge regression method determined that depth to water, net recharge, topography, and the impact of vadose zone media were the hydro-geological parameters that influenced trichloroethene pollution vulnerability in a Korean aquifer. When using these selected hydro-geological parameters, the accuracy was improved for various statistical nonlinear and artificial intelligence (AI) techniques, such as multinomial logistic regression, decision trees, artificial neural networks, and case-based reasoning. These results provide a proof of concept that the GA-Ridge regression is effective at determining influential hydro-geological parameters for the pollution vulnerability of an aquifer, and in turn, improves the AI performance in assessing groundwater pollution vulnerability. PMID:22124584

Ahn, Jae Joon; Kim, Young Min; Yoo, Keunje; Park, Joonhong; Oh, Kyong Joo

2011-11-29

71

Hydrogeologic Characterization of the Cachoeira Deposit Massif, Caetite, State of Bahia, Brazil.  

National Technical Information Service (NTIS)

The hydrogeologic applications for the characterization of rock massifs in future mining activity areas are presented. The study was performed in the Cachoeira uranium deposit (Anomaly No. 13 - Lagoa Real Project) located in the south-central portion of t...

J. A. Bottura J. L. Albuquerque Filho L. M. Ojima

1984-01-01

72

Hydrogeological Evaluation of Qatar Peninsula Using LANDSAT Imagery and Geophysical Data.  

National Technical Information Service (NTIS)

The application of image processing techniques to landsat satellite images proved to be of major significance in the evaluation of the hydrogeological situation in Qatar peninsula. The images are correlatable with the geophysical resistivity maps of the p...

M. A. Yehia I. E. Harhash

1982-01-01

73

Hydrogeology and Ground-Water Quality, Chippewa Township, Isabella County, Michigan, 2002-05.  

National Technical Information Service (NTIS)

The ground-water resource potential of Chippewa Township, Isabella County, Mich. was characterized on the basis of existing hydrogeologic data, water-level records, analyses of water samples, and interpretation of geophysical survey data. Eight ground-wat...

C. J. Hoard D. B. Westjohn

2006-01-01

74

Enhancing the Georadar Method with Applications to Hydrogeological and Environmental Studies in The Netherlands.  

National Technical Information Service (NTIS)

The subject of the thesis is enhancing the georadar method for hydrogeological and environmental studies in The Netherlands. It has been carried out at the TNO Institute of Applied Geoscience. The foundation is concerned with developments of georadar for ...

M. Csonka

1993-01-01

75

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

Microsoft Academic Search

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 km² 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

C. C. Faunt; A. K. Turner

1997-01-01

76

Hydrogeological framework of the Deccan basalt groundwater systems, west-central India  

Microsoft Academic Search

Deccan basalts of west-central India are hydrogeologically inhomogeneous rocks. A proper understanding of the physical framework\\u000a of the basalts within which groundwater resides and moves is a key to the hydrogeology of these rocks. Two types of basalt,\\u000a the vesicular amygdaloidal basalt and the compact basalt, occur as alternate layers in the volcanic pile. Although the rocks\\u000a are generally inhomogeneous,

Himanshu Kulkarni; S. B. Deolankar; A. Lalwani; B. Joseph; S. Pawar

2000-01-01

77

Hydrogeologic framework of the Puget Sound aquifer system, Washington and British Columbia  

USGS Publications Warehouse

This report presents the generalized hydrogeologic framework of the Puget Sound aquifer system in Washington and British Columbia. The framework includes a conceptual model of the division of the aquifer system into regional hydrogeologic units for describing on a regional basis the ground-water flow in the system. The conceptual model is based on an analysis of historical data and on results of cross-sectional numerical models of ground-water flow.

Vaccaro, J. J.; Hansen, Arnold J., Jr.; Jones, M. A.

1998-01-01

78

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

Microsoft Academic Search

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

T. Miller

2004-01-01

79

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

SciTech Connect

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.

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

80

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

SciTech Connect

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.

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

1997-12-31

81

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

USGS Publications Warehouse

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.

Lacombe, Pierre J.; Burton, William C.

2010-01-01

82

Geomorphology and hydrogeology of the Edwards Plateau karst, central Texas  

NASA Astrophysics Data System (ADS)

The Edwards Plateau is one of the largest continuous karst regions of the United States; yet, its geomorphic evolution has previously received little systematic study. The overall objectives of this investigation are to: (1) describe the physical characteristics of karst features, (2) determine which geomorphic and hydrogeologic controls and processes have governed their development, and (3) relate genesis of karst spatially and chronologically to the geomorphic evolution of the Edwards Plateau. Cavern development provides a record of evolution of karst and the development of major carbonate aquifers of the region. Some control on cavern development are region-wide; nevertheless, many caves exhibit characteristics that suggest a strong influence of local factors. Development of cave chambers and passages has responded to the lithic character of bedrocks. Solution conduits were guided by variations in calcite and dolomite content, thickness of strata, and frequency of bedding-plane partings. This is particularly true of the Glen Rose Formation, limestone beds of the Edwards Group, and the Gorman Formation, the three principal cave-forming units.

Kastning, E. H., Jr.

83

Hydrogeological-Geophysical Methods for Subsurface Site Characterization - Final Report  

SciTech Connect

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.

Rubin, Yoram

2001-01-01

84

Combined Estimation of Hydrogeologic Conceptual Model, Parameter, and Scenario Uncertainty  

SciTech Connect

We describe the development and application of a methodology to systematically and quantitatively assess predictive uncertainty in groundwater flow and transport modeling that considers the combined impact of hydrogeologic uncertainties associated with the conceptual-mathematical basis of a model, model parameters, and the scenario to which the model is applied. The methodology is based on an extension of a Maximum Likelihood implementation of Bayesian Model Averaging. Model uncertainty is represented by postulating a discrete set of alternative conceptual models for a site with associated prior model probabilities that reflect a belief about the relative plausibility of each model based on its apparent consistency with available knowledge and data. Posterior model probabilities are computed and parameter uncertainty is estimated by calibrating each model to observed system behavior; prior parameter estimates are optionally included. Scenario uncertainty is represented as a discrete set of alternative future conditions affecting boundary conditions, source/sink terms, or other aspects of the models, with associated prior scenario probabilities. A joint assessment of uncertainty results from combining model predictions computed under each scenario using as weights the posterior model and prior scenario probabilities.

Meyer, Philip D.; Ye, Ming; Neuman, Shlomo P.; Rockhold, Mark L.; Cantrell, Kirk J.; Nicholson, Thomas J.

2006-05-01

85

Twelve Years of Results from ODP Subseafloor "CORK" Hydrogeological Observatories  

NASA Astrophysics Data System (ADS)

The CORK ("Circulation Obviation Retrofit Kit") sealed-hole observatory was developed 12 years ago by ODP engineers and scientists to investigate in-situ hydrogeological state and processes, through long-term measurements of in-situ temperatures and pressures and sampling of in-situ fluids. CORK capabilities have been expanded recently to allow monitoring and sampling in multiple isolated horizons. To date, 18 CORK hydrological observatory sites have been established in ridge crest, ridge flank, and accretionary prism settings. Observations at these sites have provided precise constraints on the primary driving forces for, and thermal consequences of, sub-seafloor fluid flow caused by thermal buoyancy and tectonic consolidation. Deep in accretionary prisms, high formation pressures have been observed, confirming that plate boundary faults possess little strength. In young ocean crustal settings, surprisingly low lateral temperature and pressure gradients have been documented, implying that the extrusive upper oceanic crust permits efficient transport of fluid, heat, and solutes over distances of many kilometers. CORK observations have also revealed pressure variations and associated fluid flow resulting from co-seismic plate deformation and from tidal, oceanographic, and barometric loading of the seafloor. The characteristics of the formation response to seafloor loading provide constraints on formation elastic and hydrological properties, and allow quantitative estimates of crustal strain to be made from pressure transients related to tectonic events. Strain events have been observed up to 250 km away from several seismic dislocations along subduction, transform, and seafloor spreading plate boundaries.

Becker, K.; Davis, E. E.

2003-12-01

86

Hydrogeologic studies for nuclear-waste disposal in Sweden  

NASA Astrophysics Data System (ADS)

Safety Report 1997 (SR 97) of the Swedish Nuclear Fuel and Waste Management Company is a comprehensive performance assessment of three hypothetical radioactive waste repositories in Sweden. It includes hydrogeologic studies (data compilation, parameter synthesis, and groundwater flow modeling) to determine groundwater flow and the associated uncertainties for the three sites. This report reviews and compares the hydrogeologic characterization programs, the site characteristics, and the groundwater flow models used in the SR 97 performance assessment. Although differences in site-characterization programs tend to mask differences in site characteristics, the sites do have notable differences that affect the results of the performance assessment. The effects of model uncertainties evaluated by the variant cases appear to be smaller than the variability of results for the base case (best estimate of site conditions) of each site. Résumé. Le rapport sur la sûreté de 1997 (SR 97) de la Compagnie Suédoise de Gestion des Déchets Radioactifs est une évaluation d'ensemble du fonctionnement de trois sites hypothétiques de stockage de déchets radioactifs en Suède. Il comprend des études hydrogéologiques (compilation de données, synthèse des paramètres et modélisation des écoulements souterrains) pour déterminer l'écoulement souterrain et les incertitudes associées pour les trois sites hypothétiques. Ce rapport passe en revue et compare les programmes de caractérisation hydrogéologique, les caractéristiques des sites et les modèles d'écoulement de nappe utilisés dans l'évaluation du fonctionnement par SR 97. Bien que des différences dans les programmes de caractérisation des sites tendent à masquer des différences de caractéristiques des sites, les sites ne présentent pas de différences notables qui affectent les résultats de l'évaluation du fonctionnement. Les effets des incertitudes des modèles évalués par des cas variants apparaissent être moins importants que la variabilité des résultats pour le cas de base (la meilleure estimation des conditions de site) pour chaque site. Resumen. El Informe de Seguridad 1997 (SR 97) de la Compañía Sueca de Gestión de Residuos Radioactivos contiene una evaluación exhaustiva del comportamiento de tres repositorios de residuos radioactivos hipotéticos en Suecia. Incluye los estudios hidrogeológicos (toma de datos, síntesis de parámetros y modelos de flujo) realizados para determinar el flujo de las aguas subterráneas y la incertidumbre asociada a los tres repositorios hipotéticos. Este informe revisa y compara los programas de caracterización hidrogeológica, las características de cada sitio y los modelos de flujo utilizados en la evaluación SR 97. Aunque las diferencias en los programas de caracterización tienden a enmascarar las diferencias en las características de cada emplazamiento, éstos no presentan diferencias notables que puedan afectar a los resultados de los programas de evaluación de su comportamiento. La incertidumbre asociada a los modelos, evaluada mediante variaciones respecto al Caso Base (estimación óptima de las condiciones de un sitio), parece ser menor que la variabilidad de los resultados de éste en cada emplazamiento.

Walker, Douglas; Gylling, Björn; Ström, Anders; Selroos, Jan-Olof

2001-09-01

87

Hydrogeologic controls on water quality at a university dairy farm  

NASA Astrophysics Data System (ADS)

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.

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

2010-12-01

88

Hydrogeology and Simulation of Ground-Water Flow in the Thick Regolith-Fractured Crystalline Rock Aquifer System of Indian Creek Basin, North Carolina. Chapter C.  

National Technical Information Service (NTIS)

The purpose of this report is to describe the hydrogeologic framework and results of ground-water flow simulations in part of the southwestern Piedmont of North Carolina. Hydrogeologic information on the region is presented, including a conceptual model o...

C. C. Daniel D. G. Smith J. L. Eimers

1997-01-01

89

Hydrogeology of the middle Wilcox aquifer system in Mississippi  

SciTech Connect

A study has been performed to provide water resource planners and managers with hydrogeologic data on the predominantly undeveloped middle Wilcox aquifer system in Mississippi, and to describe its potential as an alternative source of water. The principal source of recharge to the middle Wilcox aquifer system is from precipitation in the outcrop area, a crescent-shaped belt extending from north to east, and dipping west to southwest. Most of the water that percolates into the ground is lost by evapotranspiration or groundwater discharge to local streams. Locally, the rate and direction of groundwater movement is controlled by the hydraulic conductivity of the sand bed and by withdrawal from wells. The potentiometric surface of the aquifer was mapped to represent the approximate altitude of water levels in wells screened in the middle Wilcox aquifer system in 1983. Near some pumping centers in and near the recharge area, water-level declines in recent years have been in the range of about 0.5 to 1.0 ft/yr. The aquifer system is capable of yielding 100-500 gpm from large wells; however, the availability of freshwater at shallower depths has limited the development of this aquifer system farther downdip, and results of aquifer tests are sparse. Groundwater in the outcrop area of the aquifer system generally is of a mixed, calcium-sodium bicarbonate type. There is a general trend of increasing pH values and concentrations of dissolved sodium, bicarbonate, nitrate, and iron with increasing depth. Typically, water in the middle Wilcox aquifer system has concentrations much smaller than the recommended limits for drinking water for nitrate, sulfate, and fluoride. Water from this aquifer system is generally suitable for most uses.

Taylor, R.E.; Arthur, J.K. (Geological Survey, Jackson, MS (United States))

1992-01-01

90

Modelling vs. Experiments in Reducing Uncertainty of Hydrogeological Regime  

NASA Astrophysics Data System (ADS)

Plavinas hydropower plant is built on the River Daugava, Latvia. Landscape in this part of Latvia is mostly shaped by the glacier during the last glacial cycle. The River Daugava basin occupies the largest part of eastern and central Latvia. The natural subsurface water flow towards the river is superimposed by the infiltration from the reservoir system established on the River Daugava for operation of HPP cascade. The geology in the region is composed of upper devonian sandstones, clays, dolomitic marls and dolomites. Plavinas HPP is built on the intersection of the contemporary river valley and a deep buried valley. It is up to 150 m deep, and intersects all upper devonian sediments. The paleo-valley is mostly filled with a glacial till and adjacent sediments, and it creates a complex groundwater relief pattern in the vicinity of the power plant. The colluvial material with characteristic high permeability values is present on the slopes along the banks of the valley. The complex drainage system is installed downstream the power plant to relief the semiperveous paleo valley filling. The considerations of HPP stability request a distributed relief system, which includes possible alternative wells insuring the operation of the system, in a case of failure of the basic drainage. The complex and essentially 3D groundwater flow pattern in vicinity of the powerhouse is described by 3D finite element model. The model is calibrated on the 30 year long observation series in approx. 400 monitoring wells. Several experiments were carried out at the power plant, during the years 2001--2002 in order to find new relief places. Mathematical model was used to simulate these experiments, and modelling allowed interpretation of the experiment results, significantly reducing the uncertainty in respect of the geological structure and hydrogeological regime. New well sites were proposed from the conclusions and conceptual solutions yielded by modelling.

Saks, T.; Sennikovs, J.; Bethers, U.

2003-04-01

91

A methodological integrated approach to optimize a hydrogeological engineering work  

NASA Astrophysics Data System (ADS)

The geoelectrical survey applied to hydraulic engineering is a well known in literature. However, despite of its large number of successful cases of application, the use of geophysics is still often not considered; this due to different reasons as: the poor knowledge of the potential performances; the difficulties in the practical implementation; the cost limitations. In this work, an integrated study of non-invasive (geoelectrical) and direct surveys is described, aimed at identifying a subsoil foundation where it possible to set up a watertight concrete structure able to protect the purifier of Senise, a little town in Basilicata Region (Southern Italy). The purifier, used by several villages, is located in a particularly dangerous hydrogeological position, as it is very close to the Sinni river, which has been obstructed from many years by the Monte Cotugno dam. During the rainiest periods, the river could flood the purifier, causing the drainage of waste waters in the Monte Cotugno artificial lake. The purifier is located in Pliocene- Calabrian clay and clay - marly formations covered by about 10m layer of alluvional gravelly-sandy materials carried by the Sinni river. The electrical resistivity tomography acquired with the Wenner Schlumberger array was revealed meaningful for the purpose to identify the potential depth of impermeable clays with high accuracy. In particular, the geoelectrical acquisition, orientated along the long side of purifier, was carried out using a multielectrodes system with 48 electrodes 2 m spaced leading to an achievable investigation depth of about 15 m The subsequent direct surveys have confirmed this depth so that it was possible to set up the foundation concrete structure with precision to protect the purifier. It is worth noting that the use of this methodological approach has allowed a remarkable economic saving as it has made it possible to correct the wrong information, regarding the depth of impermeably clays, previously inferred by the engineers.

Loperte, A.; Satriani, A.; Bavusi, M.; Cerverizzo, G.

2012-04-01

92

Hydrogeologic Controls on Lake Level at Mountain Lake, Virginia  

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

93

Hydrogeologic Framework, Water Levels, and Trichloroethylene Contamination, Naval Air Warfare Center, West Trenton, New Jersey, 1993-97.  

National Technical Information Service (NTIS)

This report presents an integrated interpretation of the hydrogeologic data collected at Sites 1 and 3 at the U.S. Naval Air Warfare Center (NAWC). This report includes maps and sections that describe and show the hydrogeologic framework of the bedrock, t...

P. J. Lacombe

2000-01-01

94

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

SciTech Connect

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.

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

1994-12-31

95

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

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

96

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

SciTech Connect

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.

Shafer, John M

2012-11-05

97

A Task-oriented Approach for Hydrogeological Site Characterization  

NASA Astrophysics Data System (ADS)

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.

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

2010-12-01

98

Linking landscape properties to local hydrogeologic gradients and plant species occurrence in minerotrophic fens of New York State, USA: A Hydrogeologic Setting (HGS) framework  

Microsoft Academic Search

We present a Hydrogeologic Setting (HGS) framework and the results of subsequent field evaluation for minerotrophic fens throughout\\u000a New York State, USA. HGS uses a hierarchical approach to link landscape properties to local environmental gradient and, therefore,\\u000a the plant communities that are associated with calcareous wetlands. This framework was organized into three general classes\\u000a (i.e., chemical, physical, and spatial), which

Kevin S. Godwin; James P. Shallenberger; Donald J. Leopold; Barbara L. Bedford

2002-01-01

99

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

Microsoft Academic Search

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

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

100

Quantitative Hydrogeological Framework Interpretations from Modeling Helicopter Electromagnetic Survey Data, Nebraska Panhandle  

Microsoft Academic Search

The need for allocation and management of water resources within the state of Nebraska has created a demand for innovative approaches to data collection for development of hydrogeologic frameworks to be used for 2D and 3D groundwater models. In 2008, the USGS in cooperation with the North Platte Natural Resources District, the South Platte Natural Resources District, and the University

J. D. Abraham; L. B. Ball; P. A. Bedrosian; J. C. Cannia; M. Deszcz-Pan; B. J. Minsley; S. M. Peterson; B. D. Smith

2009-01-01

101

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

ERIC Educational Resources Information Center

|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,…

Singha, Kamini; Loheide, Steven P., II

2011-01-01

102

Open-Source Semantic and Schematic Mediation in Hydrogeologic Spatial Data Infrastructures  

Microsoft Academic Search

A common task in cyber-based data environments, hydrogeologic or otherwise, is an initial search for data amongst distributed heterogeneous sources, followed by amalgamation of the multiple results into a single file organized using a common structure and perhaps standard content. For example, querying water well databases to obtain a list of the rock materials that occur beyond a certain ground

E. Boisvert; B. Brodaric

2008-01-01

103

Characterization of Physical and HydroGeological Properties of Kanamaru Research Site in Japan  

Microsoft Academic Search

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

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

2004-01-01

104

Role of hydrogeology in Rocky Mountain 1 underground coal gasification test, Hanna basin, Wyoming  

SciTech Connect

Experience has shown that the designs and implementation of Underground Coal Gasification (UCG) operations that are technically sound and environmentally safe require a thorough understanding of the hydrogeology of the UCG site, complemented by an understanding of the potential interactions between the elements of the hydrogeologic system and UCG process. This is significant because UCG is conducted in the saturated zone, consumes large volumes of ground water, and has the potential to adversely affect ground water quality and flow. The textural, mineralogical, chemical, and structural character of the geologic materials constituting the UCG reactor, as well as the occurrence, flow, and quality of fluids moving through that three-dimensional matrix of geologic materials, must be understood. The US Department of Energy and an industry consortium led by the Gas Research Institute recently conducted the Rocky Mountain 1 Test in the Hanna basin of Wyoming. For this test, the hydrogeologic aspects of the site were characterized to an extent unprecedented in UCG testing. This information was then used to develop and evaluate operating strategies intended to prevent or minimize contamination. Such strategies included gasifying at less than hydrostatic pressure to enhance ground water flow toward the gasification modules and to restrict contamination to the module area. Hydrogeologic information also allowed a more complete evaluation of process-setting interactions. For example, a substantial and widespread drop in elevation heat noted for the ground water in the target coal emphasized the importance of an adequate water supply for UCG, particularly in a long-term commercial operation.

Daly, D.J.; Schmit, C.R.; Beaver, F.W.; Evans, J.M. (North Dakota Mining and Mineral Resources Research Institute, Grand Forks (USA))

1989-09-01

105

Prime candidate sites for astrobiological exploration through the hydrogeological history of Mars  

Microsoft Academic Search

The hydrogeological evolution of Mars has been proposed to be dominated by the development of the Tharsis Magmatic Complex through superplume activity, with related magmatic-pulse-driven flood inundations that directly influence the shaping of the northern plains, the evolution of the atmosphere and climate, and subsurface and surface water processes. On the other hand, several possible biological models and terrestrial analogues

Alberto G. Fairén; James M. Dohm; Esther R. Uceda; Alexis P. Rodríguez; Victor R. Baker; David Fernández-Remolar; Dirk Schulze-Makuch; Ricardo Amils

2005-01-01

106

Hydrogeologic Characteristics of Four Public Drinking-Water Supply Springs in Northern Arkansas.  

National Technical Information Service (NTIS)

In October 2000, a study was undertaken by the U.S. Geological Survey (USGS) in coopera-tion with the Arkansas Department of Health to determine the hydrogeologic characteristics, including the extent of the recharge areas, for Hughes Spring, Stark Spring...

J. M. Galloway

2004-01-01

107

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

USGS Publications Warehouse

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.

Friedel, Michael J.

2008-01-01

108

Collaborative Research: hydrogeological-geophysical methods for subsurface site characterization. 1998 annual progress report.  

National Technical Information Service (NTIS)

The general purpose is the subsurface characterization of LLNL superfund site. The goal is to get the most accurate map of the hydrogeological parameters, necessary for modeling and designing the cleanup efforts at the site, using well log data and remote...

G. Mavko Y. N. Rubin

1998-01-01

109

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

Microsoft Academic Search

Due to the natural heterogeneity the hydrological modeling in the deltaic sedimentary media is complex. Reliable 3D hydrogeological models could be created by integrating properly detailed and accurate data. This data has to be properly managed and interpreted. The first task has been the creation of a geospatial database to store and to allow the management of a great amount

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

2009-01-01

110

Regional groundwater flow in mountainous terrain: Three-dimensional simulations of topographic and hydrogeologic controls  

Microsoft Academic Search

This study uses numerical simulations to define the salient controls on regional groundwater flow in 3-D mountainous terrain by systematically varying topographic and hydrogeologic variables. Topography for idealized multiple-basin mountainous terrain is derived from geomatic data and literature values. Water table elevation, controlled by the ratio of recharge to hydraulic conductivity, largely controls the distribution of recharged water into local,

Tom Gleeson; Andrew H. Manning

2008-01-01

111

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

112

Hydrogeological insights in antiquity as indicated by Canaanite and Israelite water systems  

Microsoft Academic Search

Hazor, one of the largest fortified city during the Israelite (Iron-Age) period, encompasses a gigantic underground water system within its perimeter, supplying water to thousands of its inhabitants. It is considered as the ultimate example that Iron-Age engineers had mastered the concept of regional groundwater table. However, evaluating the hydrogeological conditions and the degree of success in finding water in

Ram Weinberger; Amihai Sneh; Eyal Shalev

2008-01-01

113

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

Microsoft Academic Search

Ichnology, the study of modern and ancient traces left by organisms, has provided supplemental information to geologic subdisciplines such as sedimentology and stratigraphy. The major objective of the authors paper is to emphasize the valuable information that can be conveyed by trace fossils in the investigation of hydrogeologic units. Bioturbation has a net effect of mixing different types and layers

A. J. Martin; G. C. Simones

1992-01-01

114

Hydrogeologic assessment of escalating groundwater exploitation in the Indus Basin, Pakistan  

Microsoft Academic Search

Groundwater development has contributed significantly to food security and reduction in poverty in Pakistan. Due to rapid population growth there has been a dramatic increase in the intensity of groundwater exploitation leading to declining water tables and deteriorating groundwater quality. In such prevailing conditions, the hydrogeological appraisal of escalating groundwater exploitation has become of paramount importance. Keeping this in view,

S. Khan; T. Rana; H. F. Gabriel; Muhammad K. Ullah

2008-01-01

115

Karst Features and Hydrogeology in West-central Florida—A Field Perspective  

Microsoft Academic Search

Karst features in west-central Florida play a dominant role in the hydrogeologic framework of the region. Urban development in karst regions present unique problems for land- and water-resource managers and can potentially impact both land and water resources if not managed adequately. Understanding how karst features control ground- water flow and respond to varying hydrologic conditions is critical for effective

Ann B. Tihansky; Lari A. Knochenmus

116

The hydrogeological role of an aquitard in preventing drinkable water well contamination: A case study  

Microsoft Academic Search

Groundwater pollution has become a worrisome phenomenon, mainly for aquifers underlying industrialized areas. In order to evaluate the risk of pollution, a model of the aquifer is needed. Herewith, we describe a quasi-tridimensional model, which we applied to a multilayered aquifer where a phreatic aquifer was coupled to a confined one by means of an aquitard. This hydrogeological scheme is

G. Ponzini; G. Crosta; M. Giudici

1989-01-01

117

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

Microsoft Academic Search

Effects of subsurface deposits on nitrate loss in stream riparian zones are recognized, but little attention has been focused on similar processes occurring in upland agricultural settings. In this paper, we evaluated hydrogeologic controls on nitrate transport processes occurring in a small 7.6 ha Iowa catchment. Subsurface deposits in the catchment consisted of upland areas of loess overlying weathered pre-Illinoian

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

2007-01-01

118

Hydrogeological investigations and numerical simulation of groundwater flow in the karstic aquifer of northwestern Yucatan, Mexico  

Microsoft Academic Search

A freshwater lens underlain by saltwater exists beneath the entire northern Yucatan karst plain, Mexico. Water levels recorded in this plain, during the period June 1987 - April, 1989, were used to map the water table, identify inland hydrogeologic boundaries, and estimate the thickness of the freshwater lens using the Ghyben-Herzberg relation. The water table under most of northwestern Yucatan

Luis E. Marín; E. C. Perry; H. I. Essaid; Birgit Steinich

119

Analysis of natural groundwater level variations for hydrogeologic conceptualization, Hanford Site, Washington  

Microsoft Academic Search

This study involves the analysis of groundwater level time series for the purpose of obtaining details for a conceptual hydrogeologic model at a time when conventional hydraulic stress testing was not feasible due to regulatory considerations. The study area is located in south central Washington in the Pasco Basin which was a candidate site for underground disposal of high-level radioactive

Richard H. Nevulis; Donald R. Davis; Soroosh Sorooshian

1989-01-01

120

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...

121

Hydrogeology and Simulation of Ground-Water Flow in the Cretaceous-Paleozoic Aquifer System in Northeastern Mississippi.  

National Technical Information Service (NTIS)

This report describes the hydrogeology and simulations of ground-water flow in the Coffee Sand, Eutaw-McShan, Gordo, Coker, massive sand, and Lower Cretaceous aquifers, and two aquifers recently delineated in Paleozoic rocks in northeastern Mississippi. T...

E. W. Strom

1998-01-01

122

Hydrogeological properties of bank storage area in Changwon city, Korea  

NASA Astrophysics Data System (ADS)

Bank filtrated water has been used in developed countries such as United States, France, Germany, Austria, Nederland and so on. In Korea, most of the drinking water is provided from the surface water. However, drinking water acquisition is becoming difficult due to the degradation of surface water quality. In special, the quality of drinking water source is much lower in downstream area than in upstream area. Thus, the use of bank filtrated water is getting attracted by central and local governments in Korea. The bank filtrated water was surveyed in the areas of Yeongsan river, Nakdong river, Geum river and Han river. Up to present, however, the downstream areas of Nakdong river are most suitable places to apply the bank filtration system. This study investigates hydrogeological characteristics of bank-storage area located in Daesan- Myeon, Changwon city, adjacent the downstream of Nakdong river. Changwon city is the capital city of Gyeongsangnam-Do province. Changwon city uses water derived from Nakdong river as municipal water. However, the quantity and quality of the river water are gradually decreased. Thus, Changwon city developed two sites of bank filtration system in Daesan-myeon and Buk-myeon. Pumping rate is 2,000m3/day at present and will be increased to 60,000m3/day in Daesan-myeon site at the end of the first stage of the project. For the study, we conducted pumping tests four times on seven pumping wells (PW1, PW2, PW3, PW4, PW5, PW6, and PW7) and twelve drill holes (BH-2, OW2-OW12) in the area of 370 m x 100 m. Pumping wells PW1 and PW2 were drilled in 1999 by Samjung Engineering Co. and pumping wells PW3, PW4, PW5, PW6 and PW7 were drilled in 2000 by Donga Construction Co. and Daeduk Gongyeong Co. The pumping wells are located at 45-110 meters from Nakdong riverside. The geology of the study area is composed of volcanic rocks (Palryeongsan tuff and Jusasan andesitic rock) and alluvium. Palryeongsan tuff consists of mostly green tuff with partly tuffaceous sandstone, shale, mudstone and sandstone. Thick alluvium is overlain on Palryeongsan tuff (Samjung Engineering Co., 1999; Donga Construction Co. and Daeduk Gongyeong Co., 2000; Kim and Lee, 1964). The alluvium is composed of sand, sandy gravel and weathered zone from the surface (Table 1, Fig. 3). The aquifer is sandy gravel layer (Samjung Engineering Co., 1999). The gravel layer is thicker near the wells of PW1, PW2, PW3, and PW4 (13.5-17.5m), whereas is thinner near the wells of PW5, PW6, and PW7 (6.3-10.5m). The pumping data obtained were analyzed to determine hydraulic parameters (transmissivity and storativity) using various models of pumping test analysis. The appropriate models for the study area were found from several models. The selected model for observation well is Theis model using corrected drawdown and the selected model for pumped well is Papadopulos-Cooper model using corrected drawdown. As a result, alluvial aquifer in the study area behaviors as confined aquifer rather than phreatic aquifer. Thus, infiltration amount from the river to the aquifer in the study area is lower than that from river to phreatic aquifer for the same water level change. And also storativity of the aquifer is represented by elastic storativity rather than specific yield. Transmissivity obtained by the models ranges from 4.54x10-4 to 1.79x10-1 m2/s with arithmetic mean 2.92x10-2 m2/s. Storativity ranges from 2.59x10-4-5.54x10-1 with arithmetic mean 6.36x10-2. Frequency distribution of hydraulic parameters was determined from statistical analyses. The distribution of transmissivity values does not follow normal distribution showing skewness 2.36 and kurtosis 5.085. Aquifer heterogeneity was found by hydraulic parameters and subsurface geology data in the study area. Furthermore, hydraulic parameters obtained at a well that serves as both pumping well and observation well were compared, and the correlation equation was determined to evaluate hydraulic parameters considering aquifer loss. Transmissivity values obtained by the two cases do not show distinct correlati

Hamm, S.-Y.; Kim, H.-S.; Cheong, J.-Y.; Ryu, S. M.; Kim, M. J.

2003-04-01

123

Hydrogeologic subdivision of the Wolfcamp series and Pennsylvanian system of eastern Texas Panhandle, north-central Texas, and southwestern Oklahoma  

Microsoft Academic Search

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 report is the fifth in a series providing summary documentation of studies that subdivide the section into hydrogeologic units based on their judged relative capacities for transmitting water. This report extends the hydrogeologic

R. R. Kayal; D. J. Kistner; R. Kranes; F. P. Verock

1987-01-01

124

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

USGS Publications Warehouse

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.

Lampe, David C.

2009-01-01

125

Characterization of hydrogeologic properties for a multi-layered alluvial aquifer using hydraulic and tracer tests and electrical resistivity survey  

Microsoft Academic Search

A multi-layered aquifer, typical of riverbank alluvial deposits in Korea, was studied to determine the hydrologic properties.\\u000a The geologic logging showed that the subsurface of the study site was comprised of four distinctive hydrogeologic units: silt,\\u000a sand, highly weathered and fresh bedrock layers. The electrical resistivity survey supplied information on lateral extension\\u000a of hydrogeologic strata only partially identified by a

Jeong-Woo Kim; Heechul Choi; Jin-Yong Lee

2005-01-01

126

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

USGS Publications Warehouse

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

Thomas, Blakemore E.

2006-01-01

127

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

SciTech Connect

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.

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

1993-02-01

128

Development of three dimensional hydrogeological model and estimation of groundwater storage in Japanese islands.  

NASA Astrophysics Data System (ADS)

An optimum groundwater management which achieved a good balance between conservation and utilization is required to use the groundwater as sustainable water resources. On the recent groundwater management which uses a numerical simulation, it is important to understand the full breadth of groundwater basin and groundwater storage for evaluation the extent of human impact. However, previous study has not been clarified the full breadth of them throughout Japan, because basic information on the groundwater has not maintained still enough. The present work developed the three dimensional hydrogeological model in Japanese islands using the related database. And the groundwater storage was estimated based on the three dimensional hydrogeological model. As a result, to evaluate the full breadth of groundwater basin became possible from the sharply wide-range distribution of stratum. Moreover, we succeeded in providing the useful information such as development potential of unused groundwater resources for groundwater conservation and development.

Koshigai, Masaru; Marui, Atsunao; Ito, Narimitsu; Yoshizawa, Takuya

129

Update of the hydrogeologic model of the Cerro Prieto field based on recent well data  

SciTech Connect

The hydrogeologic model of the Cerro Prieto geothermal field in Baja California, Mexico has been updated and modified on the basis of geologic and reservoir engineering data from 21 newly completed wells. Previously, only two reservoirs had been discovered: the shallow ..cap alpha.. reservoir and the deeper ..beta.. reservoir. Recently, three deep wells drilled east of the main wellfield penetrated a third geothermal reservoir (called the ..gamma.. reservoir) below the sandstones corresponding to the ..beta.. reservoir in the main part of the field. The new well data delimit the ..beta.. reservoir, confirm the important role of Fault H in controlling the flow of geothermal fluids, and enable us to refine the hydrogeologic model of the field.

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

1986-01-01

130

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

USGS Publications Warehouse

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.

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

1993-01-01

131

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

USGS Publications Warehouse

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.

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

2008-01-01

132

Dripping into unsaturated rock underground excavations—literature review and geologic and hydrogeologic setting description  

Microsoft Academic Search

A literature review of dripping in underground constructions in deep, unsaturated geologic media was performed as part of\\u000a a phased study. The objective is to develop and test a formulation that can be used for studying unsaturated flow through\\u000a rough multi-segmented fractures, with emphasis on predicting dripping initiation time. Geologic and hydrogeologic setting\\u000a for the Yucca Mountain (YM) and its

Amvrossios C. Bagtzoglou; Daniele Cesano

2007-01-01

133

Integrating field and numerical modeling methods for applied urban karst hydrogeology  

NASA Astrophysics Data System (ADS)

Infrastructures that are constructed on unstable geologic formations are prone to subsidence. Data have been collected in the context of an upgrading project for a highway located beside a river dam that was constructed on gypsum-containing formations. Surface water infiltrates upstream of the dam, circulates through the gravel deposits and into the weathered bedrock around and beneath the dam, and exfiltrates downstream into the river. As a result, an extended weathering zone within the bedrock and preferential flow paths within voids and conduits developed as part of a rapidly evolving karst system. These processes enhance karstification in the soluble units of the gypsum-containing formations and resulted in the subsidence of the dam and the highway. Since 2006 changes in the hydrogeologic flow regime have been investigated continuously by different methods that also allow the evaluation of the long-term performance of the infrastructures. Geological (outcrops, lithostratigraphic information of boreholes), hydrometrical (extensive groundwater monitoring, dye tracer tests) and hydrogeophysical (Electrical Resistivity Tomography, ERT) field data of varying quality were integrated into high-resolution 3-D hydrogeological and 2-D karst evolution models. The applied investigative methods are validated and the sensitivity of relevant parameters governing the processes determined. It could be demonstrated that the applied methods for karst aquifer characterization complement each other and allow the interpretation of short-term impacts and long-term development on system-dynamics in the context of hydrogeologic flow regimes of karst areas. This includes the description of the transient character of the hydrogeologic flow regime during and after episodic flood events (surface-groundwater interaction, conduit and diffuse model outflow) as well as the evaluation of time scales for karst evolution. Results allow the optimization of investigative methods for similar subsidence problems, leading from general measurements and monitoring technologies to tools with predictive character.

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

2009-04-01

134

Geological, hydrogeological and hydrogeochemical characterization of groundwater bodies in the Tuscany region (Italy)  

NASA Astrophysics Data System (ADS)

This work describes the study for the characterization of meaningful groundwater bodies (CISS, Corpi Idrici Significativi Sotterranei) in Tuscany region (Italy), by way of a multidisciplinary approach, that includes geological and hydrogeological aspects, together with applied hydro-geochemistry. Due to the high degree of exploitation of such areas, both geological, and hydrogeological, as well as hydrogeochemical data are available, being produced by governmental research agencies and other interested parties. Said high human pressure resulted in local situations of degradation, such as those related to the ingression of marine and brackish water, the use of nitrogenous fertilizers in agricultural practices, and industrial processes which involve borates. An additional important aspect that emerged in this framework, is represented by the localization in some wells of this area of the Cr (VI), whose origin is not yet clearly assessed. In such context, this work is intended to contribute to the assessment of water quality at the catchment scale in the whole territory, as a first step towards a deeper assessment of origin, pathway and understanding of the transport micropollutants. A multilayer geometric reconstruction has been performed by the stratigraphic interpretation of available data in the Underground and Water Resource Data Base (BDSRI) of the Geological Survey of Tuscany Region, identifying the main aquifer levels, acquitards and acquicludes. The study of the piezometric surfaces corresponding to different hydrogeological regimes, led to the individuation of the areas characterized by the largest water exploitation, which significantly affect the quality and quantity of the resource. Hydrogeochemical characterization was carried out using: (i) a deterministic approach based on classification plots, Eh-pH diagrams, calculations of speciation-saturation, activity diagrams, etc. (ii) a geo-statistical approach, which enabled the geochemical mapping of the most meaningful parameters such as nitrate, boron and chloride concentrations. Discussion of the geological, hydrogeological and hydrogeochemical information led to the development of a conceptual model of the studied CISS water bodies, that is presented in this work.

Cerrina Feroni, A.; da Prato, S.; Doveri, M.; Ellero, A.; Lelli, M.; Marini, L.; Masetti, G.; Nisi, B.; Raco, B.; Scozzari, A.

2009-04-01

135

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

SciTech Connect

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.

Reynolds, R.; Nowacki, P.

1991-04-01

136

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

Microsoft Academic Search

A hydrogeological study was undertaken in the Zenako-Argaka catchment, near Hagere Selam in Tigray, northern Ethiopia, during\\u000a the rainy season of 2006. A geological map was produced through geophysical measurements and field observations, and a fracture\\u000a zone identified in the north west of the catchment. A perched water table was found within the Trap Basalt series above the\\u000a laterized upper

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

2011-01-01

137

On estimating the earthquake-induced changes in hydrogeological properties of the Choshuishi Alluvial Fan, Taiwan  

Microsoft Academic Search

The hydrological response of the Choshuishi alluvial fan to the 1999 Chi-Chi earthquake shows that the earthquake did impact the aquifer. The possible earthquake-induced changes in hydrogeological properties were investigated in this study. First, contour maps of the hydrologic anomaly, seismic factors, and vertical ground-surface displacement were compared qualitatively. Bull’s eye patterns were found on the contour maps of hydraulic

Kuo-Chin Hsu; Chih-Chiu Tung

2005-01-01

138

Evaluating Complex Hydrogeological Settings in a Constructed Wetland: An Isotopic\\/Chemical Mass Balance Approach  

Microsoft Academic Search

The objective of this study was to investigate the hydrogeological conditions of an artificial wetland, with four possible\\u000a sources of water: (1) ground water, (2) industrial waste water, (3) seepage from a water body to the north, and (4) seepage\\u000a from a water body to the south. The wetland was designed to improve the quality of municipal effluent and industrial

Olesya Lazareva; Thomas Pichler

2011-01-01

139

Hydrogeological characterisation of a glacially affected barrier island - the North Frisian Island of Föhr  

NASA Astrophysics Data System (ADS)

We present the application of geophysical investigations to characterise and improve the geological/hydrogeological model through the estimation of petrophysical parameters for groundwater modelling. Seismic reflection and airborne electromagnetic surveys in combination with borehole information enhance the 3-D geological model and allow a petrophysical interpretation of the subsurface. The North Sea Island of Föhr has a very complex underground structure what was already known from boreholes. The local waterworks use a freshwater body embedded in saline groundwater. Several glaciations disordered the Youngest Tertiary and Quaternary sediments by glaciotectonic thrust-faulting as well as incision and refill of glacial valleys. Both underground structures have a strong impact on the distribution of freshwater bearing aquifers. An initial hydrogeological model of Föhr was built from borehole data alone and was restricted to the southern part of the island where in the sandy areas of the Geest a large freshwater body was formed. We improved the geological/hydrogeological model by adding data from different geophysical methods, e.g. airborne electromagnetics (EM) for mapping the resistivity of the entire island, seismic reflections for detailed cross sections in the groundwater catchment area, and geophysical borehole logging for calibration of these measurements. An integrated evaluation of the results from the different geophysical methods yields reliable data. To determinate petrophysical parameter about 18 borehole logs, more than 75 m deep, and nearby airborne EM inversion models were analyzed concerning resistivity. We establish an empirical relation between measured resistivity and hydraulic conductivity for the specific area - the North Sea island of Föhr. Five boreholes concerning seismic interval velocities discriminate sand and till. The interpretation of these data was the basis for building the geological/hydrogeological 3-D model. We fitted the relevant model layers to all geophysical and geological data and created a consistent 3-D model. This model is the fundament for groundwater simulations considering forecasted changes in precipitation and sea level rise due to climate change.

Burschil, T.; Scheer, W.; Kirsch, R.; Wiederhold, H.

2012-04-01

140

Hydrogeologic assessment of escalating groundwater exploitation in the Indus Basin, Pakistan  

Microsoft Academic Search

Groundwater development has contributed significantly to food security and reduction in poverty in Pakistan. Due to rapid\\u000a population growth there has been a dramatic increase in the intensity of groundwater exploitation leading to declining water\\u000a tables and deteriorating groundwater quality. In such prevailing conditions, the hydrogeological appraisal of escalating groundwater\\u000a exploitation has become of paramount importance. Keeping this in view,

S. Khan; T. Rana; H. F. Gabriel; Muhammad K. Ullah

2008-01-01

141

Fractured rock hydrogeology (excluding modeling). (Latest citations from the Selected Water Resources abstracts database). Published Search  

SciTech Connect

The bibliography contains citations concerning the nature and occurrence of groundwater in fractured crystalline and sedimentary rocks. Techniques for determining connectivity and hydraulic conductivity, pollutant distribution in fractures, and site studies in specific geologic environments are among the topics discussed. Citations pertaining to modeling studies of fractured rock hydrogeology are addressed in a separate bibliography. (Contains a minimum of 62 citations and includes a subject term index and title list.)

Not Available

1994-01-01

142

Fractured rock hydrogeology (excluding modeling). (Latest citations from the Selected Water Resources Abstracts database). Published Search  

SciTech Connect

The bibliography contains citations concerning the nature and occurrence of groundwater in fractured crystalline and sedimentary rocks. Techniques for determining connectivity and hydraulic conductivity, pollutant distribution in fractures, and site studies in specific geologic environments are among the topics discussed. Citations pertaining to modeling studies of fractured rock hydrogeology are addressed in a separate bibliography. (Contains a minimum of 54 citations and includes a subject term index and title list.)

Not Available

1992-11-01

143

Hydrogeological and engineering geological in situ investigations for the assessment of grouting measures  

Microsoft Academic Search

Summary  By means of hydrogeological and engineering geologicalin situ investigations in three differently loosened granite deposits those parameters have been determined which permit the assessment\\u000a of the groutability. For that purpose fabric-statistical procedures, including bore-hole soundings, and joint tracing have\\u000a been performed. The resulting information about the directions of preferential water passages considerably supplements the\\u000a global values of the water absorption

A. Blinde; H. Hotzl; F. Metzler

1982-01-01

144

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

USGS Publications Warehouse

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.

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

1997-01-01

145

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

USGS Publications Warehouse

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

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

2005-01-01

146

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

SciTech Connect

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.

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

1996-09-01

147

Hydrogeological aspects of groundwater drainage of the urban areas in Kuwait City  

NASA Astrophysics Data System (ADS)

Residential areas in Kuwait City have witnessed a dramatic rise in subsurface water tables over the last three decades. This water rise phenomenon is attributed mainly to over irrigation practices of private gardens along with leakage from domestic and sewage networks. This paper presents a comprehensive study for urban drainage in two selected areas representing the two hydrogeological settings encountered in Kuwait City. In the first area, a vertical drainage scheme was applied successfully over an area of 1 km2. The system has been under continuous operation and monitoring for more than 4 years without problems, providing a permanent solution for the water rise problem in this area. The hydrogeological system has approached steady state conditions and the water levels have dropped to about 3·5 m below the ground surface. In the second area a dual drainage scheme, composing of horizontal and vertical elements, is proposed. Horizontal elements are suggested in the areas where the deep groundwater contains hazardous gases that may pose environmental problems. The proposed drainage scheme in the second area has not yet been implemented. Field tests were conducted to assess the aquifer parameters in both areas and a numerical model has been developed to predict the long-term response of the hydrogeological system in the two areas under consideration.

Al-Rashed, Muhammad F.; Sherif, Mohsen M.

2001-04-01

148

Landfill siting in New York: Case studies confirming the importance of site-specific hydrogeologic investigations  

SciTech Connect

Landfill siting is one of the most problematic environmental issues facing society today for a variety of both technical and political reasons. New York State has approached many of these issues by requiring both generalized siting studies and detailed hydrogeologic evaluation of any proposed landfill site. Geographic Information Systems (GIS) have emerged as an appropriate tool for accumulating information for preliminary decision making. Recently, Goodman and others have suggested the use of a terrain suitability map (land use map) as a mechanism for simplifying landfill siting. They propose the use of existing geologic and morphologic information to eliminate large areas of New York from consideration as potential landfill locations. The study concludes that the Appalachian Plateau region (the Southern Tier), and the Erie-Ontario Plain are the most suitable areas for landfill development in the state. An evaluation of the geology at existing landfills and the impacts that relate to the facilities has shown that suitable sites do indeed exist in areas deemed unacceptable by Goodman and others. Conversely, a number of landfills located in suitable terranes have proven to be developed on less than suitable sites. While evaluation of existing information plays an obvious role in preliminary siting studies, it is not a substitute for detailed hydrogeologic investigation. It is local hydrogeological conditions that are most important in determining the suitability of a site for landfill development rather than the regional geologic context of the site.

Cloyd, K.C.; Concannon, P.W. (New York State Dept. of Environmental Conservation, Avon, NY (United States))

1993-03-01

149

The hydrogeological role of an aquitard in preventing drinkable water well contamination: a case study.  

PubMed Central

Groundwater pollution has become a worrisome phenomenon, mainly for aquifers underlying industrialized areas. In order to evaluate the risk of pollution, a model of the aquifer is needed. Herewith, we describe a quasi-tridimensional model, which we applied to a multilayered aquifer where a phreatic aquifer was coupled to a confined one by means of an aquitard. This hydrogeological scheme is often met in practice and, therefore, models a number of situations. Moreover, aquitards play and important role in the management of natural resources of this kind. The model we adopted contains some approximations: the flow within the aquifers is assumed to be horizontal, whereas leakage is assumed vertical. The effect of some wells drilled in these aquifers is also taken into account. In order to evaluate the leakage fluxes that correspond to different exploitation conditions, we numerically solve a system of quasilinear and time-dependent partial differential equations. This model has been calibrated by the hydrogeological data from a water supply station of the Milan Water Works, where water is polluted by some halocarbons. Our simulations account for several experimental facts, both from the hydrogeological and hydrogeochemical viewpoints. Maxima of computed downward leakage rates are found to correspond with measured pollutant concentration maxima. Other results show how the aquitard can help in minimizing the contamination of drinkable water.

Ponzini, G; Crosta, G; Giudici, M

1989-01-01

150

A tectono-geomorphic model of the hydrogeology of deeply weathered crystalline rock: Evidence from Uganda  

NASA Astrophysics Data System (ADS)

Deeply weathered crystalline rock forms important aquifers for public water supply throughout low-latitude regions of Africa, South America, and Asia, but these aquifers have considerable heterogeneity and produce low well yields. Aquifers occur in the bedrock and overlying weathered mantle and are the products of geomorphic activity of meteoric water, principally deep weathering and stripping. The fundamental relationship between the hydrogeology and geomorphology of these terrains has, however, remained unresolved. This study demonstrates the ability of a recently developed tectono-geomorphic model of landscape evolution in Uganda to explain the hydrogeological characteristics of two basins, as determined using a combination of textural analysis, slug tests, packer tests, and pumping tests. The geopetal imprint of long-term deep weathering and erosional unloading is identified in the vertical heterogeneity of the fractured-bedrock and weathered-mantle aquifers; horizontal heterogeneity is lithologically controlled. The two units form an integrated aquifer system in which the more transmissive (5-20 m2/d) and porous weathered mantle provides storage to underlying bedrock fractures (transmissivity, T, ?1 m2/d). The thickness and extent of the more productive weathered-mantle aquifer are functions of contemporary geomorphic processes. The utility of the tectono-geomorphic model, applicable to deeply weathered environments, is that it coherently describes the basin-scale hydrogeological characteristics of these complex terrains.

Taylor, Richard; Howard, Ken

2000-06-01

151

Conceptual hydrogeological model of volcanic Easter Island (Chile) after chemical and isotopic surveys  

NASA Astrophysics Data System (ADS)

Most human activities and hydrogeological information on small young volcanic islands are near the coastal area. There are almost no hydrological data from inland areas, where permanent springs and/or boreholes may be rare or nonexistent. A major concern is the excessive salinity of near-the-coast wells. Obtaining a conceptual hydrogeological model is crucial for groundwater resources development and management. Surveys of water seepages and rain for chemical and environmental isotope contents may provide information on the whole island groundwater flow conditions, in spite of remaining geological and hydrogeological uncertainties. New data from Easter Island (Isla de Pascua), in the Pacific Ocean, are considered. Whether Easter Island has a central low permeability volcanic “core” sustaining an elevated water table remains unknown. Average recharge is estimated at 300-400 mm/year, with a low salinity of 15-50 mg/L Cl. There is an apron of highly permeable volcanics that extends to the coast. The salinity of near-the-coast wells, >1,000 mg/L Cl, is marine in origin. This is the result of a thick mixing zone of island groundwater and encroached seawater, locally enhanced by upconings below pumping wells. This conceptual model explains what is observed, in the absence of inland boreholes and springs.

Herrera, Christian; Custodio, Emilio

2008-11-01

152

Hydrogeological characterization on surface-based investigation phase in the Mizunami underground research laboratory project, in Japan  

SciTech Connect

The Mizunami Underground Research Laboratory (MIU) project is being carried out by Japan Atomic Energy Agency in the Cretaceous Toki granite in the Tono area, central Japan. The MIU project is a purpose-built generic underground research laboratory project that is planned for a broad scientific study of the deep geological environment as a basis of research and development for geological disposal of nuclear wastes. One of the main goals of the MIU project is to establish comprehensive techniques for investigation, analysis, and assessment of the deep geological environment. The MIU project has three overlapping phases: Surface-based Investigation (Phase I), Construction (Phase II) and Operation (Phase III). Hydrogeological investigations using a stepwise process in Phase I have been carried out in order to obtain information on important properties such as, location of water conducting features, hydraulic conductivity and so on. Hydrogeological modeling and groundwater flow simulations in Phase I have been carried out in order to synthesize these investigation results, to evaluate the uncertainty of the hydrogeological model and to identify the main issues for further investigations. Using the stepwise hydrogeological characterization approach and combining the investigation with modeling and simulation, understanding of the hydrogeological environment has been progressively improved. (authors)

Saegusa, Hiromitsu; Onoe, Hironori; Takeuchi, Shinji; Takeuchi, Ryuji; Ohyama, Takuya [Japan Atomic Energy Agency (Japan)

2007-07-01

153

Hydrogeophysical approach for the study of groundwater resources and hydrogeological features of an carbonate aquifer (Muro Lucano Mounts, Basilicata, Italy).  

NASA Astrophysics Data System (ADS)

The proposed work is about the geophysical survey applied on a carbonate aquifer to improve the hydrogeological knowledge. The optimal characterization of a groundwater resource is the conditions necessary to achieve the best location of a exploitable pumping hole. In order to characterize an exploitable aquifer, it is necessary to define the best hydrogeological model which necessarily must be supported by a lot of geological and hydrogeological data. Therefore, the integration between detailed geological data and indirect information is one of the best way to improve the groundwater model of an aquifer. This work summarizes the hydrogeological knowledge of the area of Muro Lucano village (Basilicata region). This area is characterized by the presence of an interesting karst aquifer which is made up by a carbonate ridge (Castelgrande - Muro Lucano) that tectonically dips southward and is widely covered by Pliocene deposits (sands and conglomerates), by the Argille Varicolori formation and by debris slope and landslide deposits. Besides the assessment of the complex hydrogeological framework of the area, also a balance of the groundwater resources has been carried out and, by the use of an innovative geophysical technique, a zone which is potentially suitable for the exploitation of the groundwater has been localized.

Grimaldi, Salvatore; Summa, Gianpietro; Leone, Domenico; Rizzo, Enzo

2010-05-01

154

Deformation, Structure, and Hydrogeology in the Nankai Accretionary Prism, Japan: Initial Results of ODP Leg 196 Logging While Drilling and Installation of Long-term Hydrogeological Observatories  

NASA Astrophysics Data System (ADS)

Leg 196 was the second of a two-leg program of coring, logging, and installing advanced CORK (ACORK) long-term hydrogeological observatories in the Nankai Trough, the type example of a convergent margin accreting a thick section of clastic sediments. The two-leg program was built on results from Leg 131 and was designed to define the interrelationship of deformation, structure, and hydrogeology in the Nankai accretionary prism. Leg 196 focused on logging while drilling (LWD) and installation of ACORKs at two sites near the toe of the Nankai prism: Site 808, cored during Leg 131 at the deformation front, and Site 1173, cored during Leg 190 as a reference site 12 km seaward. At Hole 1173B we collected LWD data to basement at 737 meters below seafloor (mbsf). Here the LWD data verify a subtle porosity increase with depth from 122 to 340 mbsf, followed downhole by a sharp decrease in porosity and return to a normal consolidation trend. The sharp decrease in porosity correlated with the diagenetic transition from cristobalite to quartz and is marked by a strong seismic reflector that is reproduced well by a synthetic seismogram based on the LWD data. Resistivity-at-the bit (RAB) images of the borehole show no evidence of a propagating protodecollement but, rather, reveal a basinal state of stress dominated by steeply dipping fractures and normal faults of variable strike. In Hole 808I we acquired LWD data to just below the decollement (1035 mbsf); poor drilling conditions precluded further penetration. Borehole Resitivity At Bit (RAB) images provide unparalleled structural and stratigraphic detail across the frontal thrust and decollement that indicate northwest-southeast shortening consistent with the seismic reflection data. RAB images also document borehole breakouts that show a northwest-southeast oriented maximum principal in situ stress direction, nearly parallel to the maximum principal stress direction inferred from microfaults in cores and from the plate convergence direction. Resistivity curves suggest that the frontal thrust zone has compacted, presumably due to faulting. In contrast, the resistivity data suggest that the decollement zone is dilated. These resistivity anomalies in the frontal thrust and decollement zones cannot be explained by variations in pore water composition and need to be verified by the density and porosity logs, after careful correction for borehole washouts. In Hole 1173B, a four-packer, five-screen ACORK installation was successfully emplaced. It was configured for monitoring the hydrogeological state and processes in basement and the stratigraphic projection of the decollement in the Lower Shikoku Basin formation. The ACORK in Hole 808I was configured with two packers and six screens and was intended to penetrate just to the décollement, with an emphasis on determining the hydrogeological state and processes at the frontal thrust, a fractured zone 160 m below the frontal thrust, and the decollement. Owing to extreme deterioration of drilling conditions and underreamer failure, actual penetration concluded ~36 m short of the target depth.

Klaus, A.; Mikada, H.; Becker, K.; Moore, C.

2001-12-01

155

Hydrogeologic analysis of remedial alternatives for the solar ponds plume, RFETS  

SciTech Connect

The focus of this paper is to develop a conceptual model and a hydrogeologic analysis plan for remedial alternatives being considered for the remediation of a ground water contaminant plume consisting of chiefly nitrate and uranium. The initial step in this process was to determine the adequacy of the existing data from the vast database of site information. Upon concluding that the existing database was sufficient to allow for the development of a conceptual model and then constructing the conceptual model, a hydrogeologic analysis plan was developed to evaluate several alternatives for plume remediation. The plan will be implemented using a combination of analytical and simple numerical ground water flow and contaminant transport models. This allows each portion of the study to be addressed using the appropriate tool, without having to develop a large three-dimensional numerical ground water flow and transport model, thereby reducing project costs. The analysis plan will consist of a preliminary phase of screening analyses for each of the remedial alternative scenarios, and a second phase of more comprehensive and in-depth analyses on a selected subset of remedial alternative scenarios. One of the alternatives which will be analyzed is phytoremediation (remediation of soil and ground water via uptake of chemicals by plants) because of the potential for relatively low capital and operation and maintenance costs, passive nature, and potential to provide long-term protection of the surface water. The results of these hydrogeological analyses will be factored into the selection of the preferred remedial alternative, or combination of alternatives, for the contaminant plume.

McLane, C.F. III; Whidden, J.A. [McLane Environmental, L.L.C., Princeton, NJ (United States); Hopkins, J.K. [Rocky Mountain Remediation Services, Los Alamos, NM (United States)

1998-07-01

156

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

SciTech Connect

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

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

2002-07-09

157

Understanding the hydrogeology of the Venice Lagoon subsurface with airborne electromagnetics  

NASA Astrophysics Data System (ADS)

The occurrence of alternating dry/wet conditions in transitional environments, such as wetlands, deltas, and lagoons, usually challenges the use of traditional direct and geophysical surveys for comprehensive hydrogeologic investigations. Moreover, significant mixing between continental fresh groundwater and marine salty surface waters generally takes place in these flat coastal areas. Airborne electromagnetics (AEM) is a promising tool in this respect, as it provides, in a fast and cost effective manner, large-scale distribution of bulk electrical conductivities that can be used profitably to develop hydrogeologic models. The results of a SkyTEM AEM survey in the Venice Lagoon, Italy, show the capability of this technique to significantly improve the knowledge of the hydrogeologic setting of the lagoon and nearby coastland subsurface, irrespective of the different features characterizing the area. The environment consists of salt marshes, mud flats, shallows, tidal channels, islands, together with reclaimed farmlands crossed by natural watercourses and drainage channel networks. In particular, the AEM shows (i) the presence of fresh water (with resistivity larger than 20 ? m) underneath the central part of the lagoon at depths from 10 to 25 m below m.s.l., (ii) the interface between different relevant stratigraphic units, e.g., the clayey layer bounding the Holocene-Pleistocene sedimentation, and (iii) the occurrence of areas with possible submarine fresh groundwater discharge. Moreover, the source and inland extent of the saltwater contamination in the shallow coastal aquifers along the southern margin of the lagoon are clearly revealed. AEM data were complemented with very high resolution seismic (VHRS) acquisitions. The integrated analysis of the two data sets allows distinguishing between lithostratigraphic heterogeneity and variability of the subsurface fluids.

Teatini, P.; Tosi, L.; Viezzoli, A.; Baradello, L.; Zecchin, M.; Silvestri, S.

2011-12-01

158

The worth of data in predicting aquitard continuity in hydrogeological design  

NASA Astrophysics Data System (ADS)

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 continuity. The analysis consists of four modules: (1) an aquitard realization generator based on indicator kriging, (2) a procedure for the Bayesian updating of the uncertainty with respect to aquitard windows, (3) a Monte Carlo simulation model for advective contaminant transport, and (4) an economic decision model. A sensitivity analysis for a generic design example involving a design decision between a no-action alternative and a containment alternative indicates that the data worth of a single borehole providing a hard point datum was more sensitive to economic parameters than to hydrogeological or geostatistical parameters. For this case, data worth is very sensitive to the projected cost of containment, the discount rate, and the estimated cost of failure. When it comes to hydrogeological parameters, such as the representative hydraulic conductivity of the aquitard or underlying aquifer, the sensitivity analysis indicates that it is more important to know whether the field value is above or below some threshold value than it is to know its actual numerical value. A good conceptual understanding of the site geology is important in estimating prior uncertainties. The framework was applied in a retrospective fashion to the design of a remediation program for soil contaminated by radioactive waste disposal at the Savannah River site in South Carolina. The cost-effectiveness of different patterns of boreholes was studied. A contour map is presented for the net expected value of sample information (EVSI) for a single borehole. The net EVSI of patterns of precise point measurements is also compared to that of an imprecise seismic survey.

James, Bruce R.; Freeze, R. Allan

1993-07-01

159

Maste? s Programme at Stockholm University: Hydrology, Hydrogeology and Water Resources  

NASA Astrophysics Data System (ADS)

Many environmental risks and societal concerns are directly related to the way we manage our land and water environments. The two-year master's programme "Hydrology, Hydrogeology and Water Resources" at Stockholm University, Sweden, is based on a system perspective and provides extended knowledge about water and soil-rock-sediment systems and how these interact with each other and with land use, socio-economic and water resource policy and management systems. This water system perspective includes the spreading of dissolved substances and pollutants in various water systems and associated risks for society. Questions related to water resources are also covered: the management of water resources and conflicts as well as collaborations caused by shared water resources on local, regional and global scales. A common learning objective for the courses in the programme is to be able to identify, extract and combine relevant information from databases and scientific publications, and use the resulting dataset in hydrological, hydrogeological and water resources analyses, on local, regional or global levels. Traditional classroom teaching is to large extent complemented by case study analyses, performed as project assignments. The importance of water resources for both the society and the environment is emphasized through applications to practical water resources management challenges in society. The courses in this program include the following topics: · Hydrological and hydrogeological processes, main components of the water cycle (e.g., precipitation, evapotranspiration, discharge) and the spreading of dissolved substances and pollutants in various water systems. · Water resources and water quality, pollution spreading through surface, ground and coastal water systems, as well as vulnerability and resilience of water resources. · Regional analyses related to global water resource vulnerability and resilience. · Models and information systems as important tools for dealing with hydrologic and hydrogeologic problems, and as a basis for sustainable governance and management of water resources. · Mathematical equations that are used in models for describing water flow and contaminant transport and their physico-chemical basis. · Handling of hydrologic data including methods for time series analyses and management of spatial data using geographic information systems (GIS) and geostatistics. · Integrated natural and social science studies of natural and anthropogenic flows of water, nutrients, pollutants and other biogeochemical substances that are important for environmental risk assessment, ecosystem development, and management of environmental resources.

Jarsjö, J.; Destouni, G.; Lyon, S. W.; Seibert, J.

2009-04-01

160

Hydrogeological Investigations in Deep Wells at the Meuse/Haute Marne Underground Research Laboratory  

NASA Astrophysics Data System (ADS)

ANDRA (Agence Nationale pour la Gestion de Déchets Radioactifs) has developed an integrated approach to characterizing the hydrogeology of the carbonate strata that encase the Callovo-Oxfordian argillite at the Meuse/Haute-Marne Laboratory site. The argillites are difficult to characterize due to their low permeability. The barrier properties of the argillites can be inferred from the flow and chemistry properties of the encasing Oxfordian and Dogger carbonates. Andras deep hole approach uses reverse air circulation drilling, geophysical logging, flow meter logging, geochemical sampling, and analyses of the pumping responses during sampling. The data support numerical simulations that evaluate the argillites hydraulic behaviour.

Delay, Jacques; Distinguin, Marc

161

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

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.

Anderman, Evan R.; Hill, Mary C.

2003-01-01

162

Applications of Ground Penetrating Radar to Hydrogeological Investigations in Coastal Environments  

NASA Astrophysics Data System (ADS)

Ground penetrating radar is sensitive to the porosity and compositional variations common in coastal sands, and hence has become a staple tool for coastal stratigraphers. Under the right circumstances, GPR can also provide useful information on surficial aquifer hydrogeology in coastal zones. Here we present examples of the primary uses for GPR in coastal hydrogeology: (1) to identify depth to the water table; (2) to estimate the depth to the freshwater/saltwater interface; (3) to map hydrostratigraphic units; and (4) to track water flow and changes in water content in surficial aquifers. The water table generally produces a distinct GPR reflection where the capillary zone is thin relative to the radar wavelength. Uncertainties in the water table depth come primarily from uncertainties in the wave velocity and in the thickness of the capillary fringe. The freshwater/saltwater interface is typically too gradational to reflect energy; instead the radar pulse is attenuated. For some GPR instruments, a very shallow freshwater/saltwater interface can cause saturation in pre-amplifiers, resulting in a spurious high-frequency pulse in the record. On a coastal barrier island in the Outer Banks of North Carolina, GPR proved an excellent tool for mapping a muddy marsh layer that serves as a (semi) confining unit for a perched water table. In siliciclastic and carbonate units in Florida, repeated GPR surveying of individual sites has been used for qualitative tracking of unsaturated zone flow, water table migration, and changes in water content.

Kruse, S.; Grasmueck, M.; Bentley, L.; Guha, S.; Juster, T.

2005-12-01

163

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

NASA Astrophysics Data System (ADS)

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

Mádl-Sz?nyi, Judit; Tóth, József

2009-06-01

164

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

USGS Publications Warehouse

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)

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

1984-01-01

165

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

SciTech Connect

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

Bradley, R.G.; Yelderman, J.C. Jr. (Baylor Univ., Waco, TX (United States). Geology Dept.)

1993-02-01

166

Defining Hydrogeological Boundaries for Mountain Front Recharge (MFR) Predictions in Multi-Catchment Mountainous Systems  

NASA Astrophysics Data System (ADS)

Cross-catchment groundwater flow in mountainous watersheds results from the development of local, intermediate, and regional groundwater flow pathways in multi-catchment systems. As such, hydrogeological analysis (e.g. water balance calculations and numerical modelling) to assess contributions of groundwater to mountain front recharge (MFR) must consider the choice of boundaries based on hydrological divides. Numerical 3-dimensional hydrogeological modelling was completed using FeFlow (DHI-WASY), for conceptual regional-scale multi-catchment systems; extending from a watershed boundary to a mountain front. The modelled systems were designed to represent major ridge and valley configurations observed in mountainous watersheds including: nested, adjacent, disconnected, non-parallel, and parallel catchments. Both homogeneous and heterogeneous hydraulic conductivity scenarios were simulated; with the heterogeneous scenario including a shallow zone of higher hydraulic conductivity bedrock overlying less permeable bedrock. The influence of cross-catchment flow in the development of groundwater flow pathways contributing to MFR was examined. The results provide a basis for identifying topographic scenarios where contributions to MFR may originate outside hydrological divides. This understanding will contribute to improving MFR predictions using both the numerical modelling approach and the water balance approach.

Neilson-Welch, L. A.; Allen, D. M.

2010-12-01

167

Environmental and hydrogeological problems in karstic terrains crossed by tunnels: a case study  

NASA Astrophysics Data System (ADS)

The construction of one of the high-speed railway tunnels between Malaga and Córdoba (South Spain) beneath the Abdalajís mountains occasioned a series of hydrogeological problems with geotechnical and environmental impacts. The double tunnel, 7,300 m in length, runs south to north across several lines of small, calcareous mountains that have a highly complex structure. Beneath the Jurassic limestones lie Triassic clays and evaporites. Overlying the limestones is an essentially marly and limestone-marl Cretaceous series, which culminates with Miocene marls containing some organic matter. These mountains have generated springs that are used for urban water supply and irrigation, as well as drinking fountains in the surrounding villages. The initial water level in the aquifer series varied from 400 to 650 m above sea level. After drilling approximately 2,900 m, and intercepting a fracture zone within the carbonate rocks, a sudden water eruption occurred that reached a peak flow of 800 L/s. After a short while, spring discharges dried up, leading to a public protest. In this paper, we describe the geological and hydrogeological settings, the development of the aquifer as the drilling operation proceeded, the measures adopted and the responses subsequent to completion of the tunnel, including the effect of rainfall on the recovery of water levels. Lastly, a generalized estimate is made of how the system functions, and a forecast is made for recovery of its equilibrium.

Gisbert, J.; Vallejos, A.; González, A.; Pulido-Bosch, A.

2009-07-01

168

Constraining fault-zone hydrogeology through integrated hydrological and geoelectrical analysis  

NASA Astrophysics Data System (ADS)

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

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

2010-08-01

169

Groundwater availability under hydrogeologic and ecological constraints: A regional assessment for the Great Lakes Basin  

NASA Astrophysics Data System (ADS)

The linkage between groundwater and surface water resources is recognized to have important implications for ecosystem concerns. In particular, capture of streamflows related to groundwater abstractions in water resources management has been emphasized. 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. Although the Great Lakes Basin is a relatively water rich region, the large contribution of groundwater to streamflows and widespread use of surficial aquifers make the region sensitive to environmental impacts from groundwater abstractions. An equation that relates groundwater extractions to transient streamflow depletion is coupled with an inverse distance weighting technique to distribute the capture between stream segments. Maximum allowable pumping rates that do not result in the exceedance of streamflow depletion criteria are determined at randomly generated locations across the Great Lakes Basin. The local allowable pumping rates depend on aquifer hydrogeology and stream network geometry and flows. Analysis is conducted to elucidate which hydrologic characteristics play the most important roles in determining allowable pumping rates. Sensitivity to factors such as pumping time and environmental flow standards is explored. An understanding of how both environmental flow constraints and hydrogeologic characteristics define groundwater availability and which characteristics and spatial variables have the greatest influence on potential streamflow depletions can aid in water resources management and policy decisions.

Watson, K. A.; Mayer, A. S.; Reeves, H. W.

2011-12-01

170

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

SciTech Connect

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

NONE

1984-05-01

171

Strategic groundwater resources in the Tagliamento River basin (northern Italy): hydrogeological investigation integrated with geophysical exploration  

NASA Astrophysics Data System (ADS)

The western sector of the Tagliamento River basin (Friuli Venezia-Giulia Region; northern Italy) is characterized by important water resources, both superficial and underground. In particular, in the Quaternary deposits of the plain, up to a depth of 500 m, six artesian aquifer systems exist. A large amount of lithological, geomorphological, and hydrogeological data is presented, allowing for definition of (a) the principal aquifer system of the area to a depth of about 500 m; (b) geometrical characteristics of the aquifers (thickness, lateral extension, etc); (c) the hydraulic parameters (hydraulic conductivity, transmissivity); (d) chemico-physical characteristics of the water; and (e) vulnerability to pollution of the aquifer systems. In a test area, where many boreholes were drilled for fresh water supply, the conceptual hydrogeological model was integrated by a detailed and repeated three-dimensional (3D) resistivity survey using combined electrical resistivity tomography (ERT) and time-domain electromagnetic (TDEM) soundings. ERT investigation was mainly used to get detailed information about geometry and porosity of the overburden and to calibrate the shallowest TDEM information.

Rapti-Caputo, Dimitra; Bratus, Antonio; Santarato, Giovanni

2009-09-01

172

Numerical Groundwater-Flow Model of the Minnelusa and Madison Hydrogeologic Units in the Rapid City Area, South Dakota.  

National Technical Information Service (NTIS)

The city of Rapid City and other water users in the Rapid City area obtain water supplies from the Minnelusa and Madison aquifers, which are contained in the Minnelusa and Madison hydrogeologic units. A numerical groundwater-flow model of the Minnelusa an...

2009-01-01

173

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

USGS Publications Warehouse

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.

Banta, Edward R.; Provost, Alden M.

2008-01-01

174

Hydrogeologic subdivision of the Wolfcamp series and Pennsylvanian system of the Swisher Study Area, Texas: Revision 1: Topical report  

Microsoft Academic Search

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 report provides summary documentation of studies that subdivide the section into hydrogeologic units based on their judged relative capacities for transmitting water. This particular study area comprises eight counties in Texas, including

P. C. Siminitz; E. A. Warman

1987-01-01

175

Hydrogeologic subdivision of the Wolfcamp series and Pennsylvanian system of eastern Texas Panhandle, north-central Texas, and southwestern Oklahoma  

SciTech Connect

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 report is the fifth in a series providing summary documentation of studies that subdivide the section into hydrogeologic units based on their judged relative capacities for transmitting water. This report extends the hydrogeologic study area to the eastern Texas Panhandle, north-central Texas, and southwestern Oklahoma. It includes 37 counties in Texas and Oklahoma. 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. Hydrogeologic units are defined and characterized so that appropriate porosity and permeability values can be assigned to each unit during construction of the numerical models (not part of this study), and so that modelers can combine units where necessary. 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). 44 refs., 32 figs., 1 tab.

Kayal, R.R.; Kistner, D.J.; Kranes, R.; Verock, F.P.

1987-03-01

176

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

Microsoft Academic Search

Defining rational and effective hydrogeological data acquisition strategies is of crucial importance since financial resources available for such efforts are always limited. Usually such strategies are developed with the goal of reducing uncertainty, but less often they are developed in the context of the impacts of uncertainty. This paper presents an approach for determining site characterization needs based on human

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

2007-01-01

177

Identification of Groundwater Contamination Causes Around Subway Tunnels at a Coastal Area in Korea, Using Hydrogeological and Geostatistical Analyses  

Microsoft Academic Search

The cause for the deterioration of groundwater quality was identified by hydrogeological investigations and geostatisitical analyses at a coastal area in Busan, Korea. The city has many tunnels for three subway lines, for communication cables and for electrical cables under the ground. The groundwater levels of 135 wells were measured during the dry and wet seasons. The average groundwater level

D. Kim; T. Kim; S. Chung; S. Yang

2009-01-01

178

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

USGS Publications Warehouse

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

Galloway, J. M.

1999-01-01

179

Modelling of mine flooding and consequences in the mine hydrogeological environment: flooding of the Koenigstein mine, Germany  

Microsoft Academic Search

The approach to modelling of flooding of the underground mines and hydrogeological consequences in the downstream aquifers of the mine followed in the WISMUT Decommissioning and Reclamation Programme is illustrated for the case of the uranium underground leach mine in Koenigstein, near Dresden, Germany. The modelling of the present and future quantity and quality of the water in the mine

A. T. Jakubick; U. Jenk; R. Kahnt

2002-01-01

180

Hydrogeologic Behavior of an Alluvial Aquifer, Salta Province, Argentina: Simulations of Hydraulic Conductivity Field, Groundwater Flow, and Chloride Migration  

Microsoft Academic Search

This work was designed to analyze the hydrogeological behavior of an alluvial aquifer in the River Mojotoro basin site in the Province of Salta, Argentina. The study area presents coarse-grained sediments with high infiltration capacity. The hydraulic conductivity field is affected by the physical heterogeneity of the medium and a geostatistical method, kriging, was used to construct this field from

Jacqueline Köhn; Eduardo E. Kruse; Juan E. Santos

2002-01-01

181

Integrating indigenous ecological and scientific hydro-geological knowledge using a Bayesian Network in the context of water resource development  

NASA Astrophysics Data System (ADS)

We model indigenous, ecological knowledge of valuable aquatic species.The indigenous hydro-ecological understanding is combined with scientific hydro-geological knowledge.We predict a negative effect of both ground water and surface water extraction on most fish species.The model will assist understanding and collaboration with indigenous people.

Liedloff, A. C.; Woodward, E. L.; Harrington, G. A.; Jackson, S.

2013-08-01

182

HYDROGEOLOGICAL CHARACTERISATION OF POTENTIAL RADIOACTIVE WASTE REPOSITORY HOST ROCKS AT TWO RESEARCH SITES IN THE UNITED KINGDOM  

Microsoft Academic Search

Since 1978 hydrogeological investigations have been carried out within the Strath Halladale Granite of Caithness and the Cretaceous\\/Jurassic mudstone sequence beneath Harwell in Oxfordshire. Among the techniques used to obtain information on groundwater regimes and flow rates have been down-hole testing, geophysical logging and groundwater chemistry studies. A versatile straddle packer system has been developed specifically for these poorly permeable

J D MATHER

183

Impact of long-term drainage on hydrogeological and biogeochemical processes near a drainage ditch in a Canadian peatland  

Microsoft Academic Search

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

B. Kopp; J. Fleckenstein; C. Blodau

2009-01-01

184

Hydrogeological aspects and environmental concerns of the New Valley Project, Western Desert, Egypt, with special emphasis on the southern area  

Microsoft Academic Search

The New Valley Project has been given much attention in the past 20 years especially from the hydrogeological point of view concerning groundwater utilization for the reclamation of a large area of the Western Desert. Lithological, petrophysical, and petrographical studies were conducted on four wells south of Beris Oasis, namely Beris 20, Beris 15, Beris 14, and Beris 13, and

Fakhry A. Assaad

1988-01-01

185

Extraterrestrial hydrogeology  

Microsoft Academic Search

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

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

2005-01-01

186

Constraining Fault-Zone Hydrogeology through Integrated Hydrological and Geoelectrical Analysis  

NASA Astrophysics Data System (ADS)

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

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

2009-12-01

187

Geophysical modeling and geochemical analysis for hydrogeologic assessment of the Steamboat Hills area, Nevada  

NASA Astrophysics Data System (ADS)

Three studies constitute the hydrogeologic assessment of the Steamboat Hills area, Washoe County, Nevada. Geophysical modeling and geochemical analysis are used to assess the hydrogeologic connection between a fractured bedrock geothermal system used to produce electrical power and surrounding alluvial aquifer basins used for municipal drinking water supply. Understanding the hydrogeologic connection between these two water resources is important for long-term management of these resources. Coupled 2.75-D forward modeling of multiple gravity and aeromagnetic profiles constrained by geological and physical properties (density, magnetic susceptibility, remanent magnetic) data yields a detailed 3-D geologic model of the geothermal system and the alluvial basins. A new method is presented for modeling the geothermal reservoir based on altered physical properties of host rock that yields a reservoir volume estimate that is double the previously assumed volume. The configuration of the modeled geothermal reservoir suggests that a previously unrecognized thermal water up-flow zone may exist along the west flank of the Steamboat Hills. Model results delineate the elevation and thickness of geologic units that can be used in numerical modeling of groundwater flow, planning exploration drilling, and evaluating fully 3-D forward modeling software. The Steamboat Hills geothermal resource area offers an excellent opportunity to test an exploration strategy using magnetics. A zone of demagnetized rock within the geothermal resource area resulting from thermochemical alteration due to thermal water flow along faults and fractures is apparent as an aeromagnetic low anomaly. Anomalously low ground magnetic data delineate a fault that conducts thermal water from the geothermal system to an alluvial aquifer. Vertical magnetic susceptibility from core measurements yields an average value for altered granodiorite used in forward modeling. Permeable fractures and a major fault zone noted in the core hole log correspond to low magnetic susceptibility values suggesting thermal alteration or mineral replacement along fractures. Temporal variations in B and Cl concentrations, water levels, and temperature are used to assess the mixing of thermal and non-thermal waters in alluvial aquifers north of the Steamboat Hills. Previously undocumented temporal variations indicate that the degree of mixing is dependent on proximity to north-trending faults connecting the geothermal reservoir and the alluvial aquifer. Mixing trends at selected wells suggest temperature dependent boron adsorption.

Skalbeck, John David

2001-07-01

188

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

USGS Publications Warehouse

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

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

1984-01-01

189

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

USGS Publications Warehouse

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. Probably the most economical plan would involve storage in an evaporation pond. The reservoir site must be large enough to provide an adequate evaporative surface over the life of the project, and be located and constructed to prevent brine contamination of other ground or surface waters either by seepage losses from the reservoir or by flood overflows. The proposed Radium Reservoir, located approximately 10 mi east of the Dolores River and between Paradox Valley and Gypsum Valley, would apparently serve as a satisfactory site for an evaporation pond. (Woodard-USGS)

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

1978-01-01

190

Cape Cod Aquifer Management Project (CCAMP): hydrogeologic papers. Report for August 1985-December 1987  

SciTech Connect

The project was initiated in 1985 with the goal of studying existing federal, state, and local programs for protecting and preserving Cape Cod's sole-source aquifer. To meet this need, the Massachusetts Department of Environmental Quality Engineering and the U.S. Environmental Protection Agency's Region 1 in cooperation with the Cape Cod Planning and Economic and Development Commission and the U.S. Geological Survey initiated a two-year study to determine the adequacy of current ground-water protection programs and to recommend improvements. In the process of gathering and evaluating hydrogeological data from the Towns of Barnstable and Eastham, the CCAMP Aquifer Assessment Committee developed the papers which are the subject of this publication. These studies formed the technical basis for groundwater resource management decision making.

Not Available

1988-09-01

191

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

USGS Publications Warehouse

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.

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

2009-01-01

192

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

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

193

Open-Source Semantic and Schematic Mediation in Hydrogeologic Spatial Data Infrastructures  

NASA Astrophysics Data System (ADS)

A common task in cyber-based data environments, hydrogeologic or otherwise, is an initial search for data amongst distributed heterogeneous sources, followed by amalgamation of the multiple results into a single file organized using a common structure and perhaps standard content. For example, querying water well databases to obtain a list of the rock materials that occur beyond a certain ground depth, represented in some specific XML dialect. This task is often achieved with the aid of open geospatial technologies (OGC), which conveniently enable interoperability at the system and syntax levels by providing standard web service interfaces (WMS, WFS, WCS) and a standard data transfer language (GML). However, at present such technologies, which are mainly non-open source, provide minimal support for interoperating at the schematic and semantic levels, meaning it is difficult to query the data sources and obtain results in a common data structure populated with standard content. Classical data integration systems provide mediator and wrapper middleware to address this issue: mediators dispatch queries to distributed data repositories and integrate query results, while wrappers perform translation to common standards for both queries and results, and these actions are typically supported by ontologies. Under this classical scenario existing open geospatial services can be considered wrappers with minimal translation capacity, thus requiring a mediator to both integrate and translate. Consequently, we have used open source components to develop a re-usable mediator that operates as a virtual open geospatial web service (WFS), one that integrates and translates both query requests and results from OGC-wrapped data sources to common standards. The mediator is designed as a customizable XML processing pipeline that operates on declarative descriptions that support schematic and semantic translation. It is being implemented in virtual environments for hydrogeology to enhance knowledge of Canada's watersheds, as well as in environments aimed at the delivery of geologic information. Discussed will be the role and design of the mediator and its implementation in a distributed groundwater information context.

Boisvert, E.; Brodaric, B.

2008-12-01

194

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

PubMed

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

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

2013-06-07

195

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

SciTech Connect

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

Martin, A.J. (Emory Univ., Atlanta, GA (United States). Geosciences Program); Simones, G.C. (South Carolina Water Resources Commission, Columbia, SC (United States))

1992-01-01

196

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.  

National Technical Information Service (NTIS)

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...

A. E. LaMotte A. J. Sekellick B. J. Fleming

2013-01-01

197

Data Management within the Hydrogeology Data Acquisition System (HDAS) (Gestion des Donnees du Systeme d'Acquisition des Donnees Hydrogeologiques (SADH)).  

National Technical Information Service (NTIS)

Routine groundwater level monitoring of surface boreholes on the lease area of the Underground Research Laboratory has been ongoing since 1980. The report deals with the methods of data collection, the evolution of the Hydrogeology Data Acquisition System...

D. R. Daymond

1994-01-01

198

Hydrogeologic Framework and Ground-Water Budget of the Spokane Valley-Rathdrum Prairie Aquifer, Spokane County, Washington, and Bonner and Kootenai Counties, Idaho.  

National Technical Information Service (NTIS)

The U.S. Geological Survey, in cooperation with the Idaho Department of Water Resources and Washington State Department of Ecology, investigated the hydrogeologic framework and ground-water budget of the Spokane Valley-Rathdrum Prairie (SVRP) aquifer loca...

J. R. Bartolino S. C. Kahle

2007-01-01

199

Calandar year 1996 annual groundwater monitoring report for the Bear Creek Hydrogeologic Regime at the US Department of Energy Y-12 Plant, Oak Ridge, Tennessee.  

National Technical Information Service (NTIS)

This annual monitoring report contains groundwater and surface water monitoring data obtained in the Bear Creek Hydrogeologic Regime (Bear Creek Regime) during calendar year (CY) 1996. The Bear Creek Regime encompasses a portion of Bear Creek Valley (BCV)...

1997-01-01

200

Calendar year 1996 annual groundwater monitoring report for the Chestnut Ridge Hydrogeologic Regime at the U.S. Department of Energy Y-12 Plant, Oak Ridge, Tennessee.  

National Technical Information Service (NTIS)

This annual monitoring report contains groundwater and surface water monitoring data obtained in the Chestnut Ridge Hydrogeologic Regime (Chestnut Ridge Regime) during calendar year (CY) 1996. The Chestnut Ridge Regime encompasses a section of Chestnut Ri...

1997-01-01

201

A summary and discussion of hydrologic data from the Calico Hills nonwelded hydrogeologic unit at Yucca Mountain, Nevada  

SciTech Connect

This report is a summary of available hydrologic data from in situ and laboratory testing of the Calico Hills nonwelded hydrogeologic unit, including hydraulic conductivity, porosity, saturation, pore-size distribution and parameters from curve-fits to pressure-saturation data. Sample statistics of hydraulic conductivity, porosity and saturation data for vitric, devitrified and zeolitic tuffs are presented and discussed. While a high degree of variability is observed in both laboratory and in situ hydraulic conductivity measurements, uncertainties arising from differences in size of laboratory test samples, sample handling, test procedures and insufficient number of samples point to the need for additional data of specific types to adequately characterize the unit. Hydrologic issues related to transport analysis in the Calico Hills nonwelded hydrogeologic unit at Yucca Mountain are discussed together with recommendations for future work. The compiled data are included as an appendix.

Loeven, C.

1993-01-01

202

Changes in hydrogeological properties of the River Choushui alluvial fan aquifer due to the 1999 Chi-Chi earthquake, Taiwan  

Microsoft Academic Search

Changes in hydrogeological properties of the River Choushui alluvial fan aquifer before and after the 1999 Chi-Chi earthquake,\\u000a Taiwan, have been identified using pumping tests. Three wells, SH2, YL2 and SC2, located in a compressional zone with high\\u000a coseismic groundwater levels, were tested. The threshold of the aquifer deformation with respect to transmissivity (T) is greater than that with respect

Cheng-Shin Jang; Chen-Wuing Liu; Yeeping Chia; Li-Hsin Cheng; You-Ching Chen

2008-01-01

203

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

SciTech Connect

This annual groundwater quality report (GWQR) contains groundwater and surface water quality data obtained during the 1994 calendar year (CY) at several hazardous and non-hazardous waste-management facilities associated with the U.S. Department of Energy (DOE) Y-12 Plant located on the DOE Oak Ridge Reservation (ORR) southeast of Oak Ridge, Tennessee. The sites addressed by this document are located in Bear Creek Valley (BCV) west of the Y-12 Plant complex (directions in this report are in reference to the Y-12 administrative grid system) within the Bear Creek Hydrogeologic Regime (Bear Creek Regime), one of three hydrogeologic regimes defined for the purposes of groundwater and surface water quality monitoring at the Y-12 Plant. The Environmental Management Department of the Y-12 Plant Health, Safety, Environment, and Accountability (HSEA) Organization manages the groundwater monitoring activities in the Bear Creek Regime under the auspices of the Y-12 Plant Groundwater Protection Program (GWPP). The purpose of the GWPP is to characterize the hydrogeology and to monitor groundwater quality at the Y-12 Plant and surrounding area to provide for protection of groundwater resources consistent with federal, state, and local requirements and in accordance with DOE Orders and Martin Marietta Energy Systems, Inc. (Energy Systems) corporate policy. The annual GWQR for the Bear Creek Regime is completed in two parts. Part 1 (this report) consists primarily of data appendices and serves as a reference for the groundwater quality data obtained each CY under the lead of the Y-12 Plant GWPP. Part 2 of the report, to be issued mid-year, will contain an evaluation of the data with respect to regime-wide groundwater quality, present the findings and status of ongoing hydrogeologic studies, describe changes in monitoring priorities, and present planned modifications to the groundwater sampling and analysis program for the following CY.

NONE

1995-02-01

204

Hydrogeological aspects and environmental concerns of the New Valley Project, Western Desert, Egypt, with special emphasis on the southern area  

Microsoft Academic Search

The New Valley Project has been given much attention in the past 20 years especially from the hydrogeological point of view\\u000a concerning groundwater utilization for the reclamation of a large area of the Western Desert. Lithological, petrophysical,\\u000a and petrographical studies were conducted on four wells south of Beris Oasis, namely Beris 20, Beris 15, Beris 14, and Beris\\u000a 13, and

Fakhry A. Assaad

1988-01-01

205

A Three-Dimensional Subseafloor Observatory Network for Cross-Hole, Hydrogeologic Experiments Established in the Northeast Pacific Ocean  

NASA Astrophysics Data System (ADS)

The upper oceanic crust, composed mainly of basalt, comprises the largest aquifer on Earth. Global fluid fluxes through the upper oceanic crust are at least as large as the annual riverine flux to the ocean, and influence a diverse array of processes and properties, including the thermal state and evolution of oceanic plates; alteration of the lithosphere and the chemistry of flowing fluids; establishment and maintenance of vast subseafloor microbial ecosystems; and diagenetic, seismic, and magmatic activity along plate-boundary faults. Active experiments are needed in the oceanic crust to determine hydrogeologic properties at a crustal scale, and to quantify linkages between thermal, fluid, solute, and biological processes. The first expedition of the Integrated Ocean Drilling Program established two new subseafloor observatories within 3.5 Ma crust in the northeast Pacific Ocean, and replaced a previously-deployed observatory, in anticipation of planned cross-hole tests and related experiments. The new holes extend up to 320 m into basement and isolate distinct depth intervals. All of the new observatories are instrumented with autonomous temperature loggers, osmotic fluid samplers, and microbiological incubation substrate. Future experiments will include hydrogeologic tests to determine fluid transmission and storage properties, at cross-hole distances of 35 to 2200 m, tracer tests to quantify rates and modes of solute transport, and seismic experiments to elucidate relations between velocity and hydrogeologic anisotropy.

Fisher, A. T.; Wheat, C. G.; Becker, K.; Davis, E.; Jannasch, H.; Hulme, S.; Nielsen, M.; Schroeder, D.; Dixon, R.; Urabe, T.; Klaus, A.; Pettigrew, T.; MacDonald, R.; Meldrum, R.; Fisk, M.; Cowen, J.; Bach, W.; Scientific Party, I. 3

2004-12-01

206

Characterization of Spatial Variability of Hydrogeologic Properties for Unsaturated Flow in the Fractured Rocks at Yucca Mountain, Nevada  

SciTech Connect

The spatial variability of layer-scale hydrogeologic properties of the unsaturated zone (UZ) at Yucca Mountain, Nevada, is investigated using inverse modeling. The thick UZ is grouped into five hydrostratigraphic units and further into 35 hydrogeologic layers. For each layer, lateral variability is represented by the variations in calibrated values of layer-scale properties at different individual deep boreholes. In the calibration model, matrix and fracture properties are calibrated for the one-dimensional vertical column at each individual borehole using the ITOUGH2 code. The objective function is the summation of the weighted misfits between the ambient unsaturated flow (represented by measured state variables: water saturation, water potential, and pneumatic pressure) and the simulated one in the one-dimensional flow system. The objective function also includes the weighted misfits between the calibrated properties and their prior information. Layer-scale state variables and prior rock properties are obtained from their core-scale measurements. Because of limited data, the lateral variability of three most sensitive properties (matrix permeability, matrix of the van Genuchten characterization, and fracture permeability) is calibrated, while all other properties are fixed at their calibrated layer-averaged values. Considerable lateral variability of hydrogeologic properties is obtained. For example, the lateral variability of is two to three orders of magnitude and that of and is one order of magnitude. The effect of lateral variability on site-scale flow and transport will be investigated in a future study.

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

2002-05-21

207

Hydrogeologic subdivision of the Wolfcamp series and Pennsylvanian system of the Swisher Study Area, Texas: Revision 1: Topical report  

SciTech Connect

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 report provides summary documentation of studies that subdivide the section into hydrogeologic units based on their judged relative capacities for transmitting water. This particular study area comprises eight counties in Texas, including Swisher 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. Hydrogeologic units are defined and characterized so that appropriate porosity and permeability values can be assigned to each during construction of the numerical models and so that modelers can combine units where necessary. 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). 15 refs., 52 figs., 1 tab.

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

1987-08-01

208

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

SciTech Connect

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.

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

1997-12-31

209

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

USGS Publications Warehouse

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.

Fischer, John N.

1986-01-01

210

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

NASA Astrophysics Data System (ADS)

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.

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

2012-08-01

211

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

NASA Astrophysics Data System (ADS)

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

Thieme, D. M.; Denizman, C.

2011-12-01

212

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

USGS Publications Warehouse

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.

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

213

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

NASA Astrophysics Data System (ADS)

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

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

2009-05-01

214

A poly morphological landform approach for hydrogeological applications in heterogeneous glacial sediments  

NASA Astrophysics Data System (ADS)

The `poly morphological (PM) concept' is used to assess geological heterogeneity in glacial sediments and to evaluate groundwater recharge to aquifers, especially those underlying clay till. The novelty of the PM concept is that it enhances the knowledge of, especially, heterogeneity of till units in geological models by using superimposed geomorphological units with typical sediment types related to the individual landforms. The PM concept is demonstrated through the construction of a poly morphological map for Zealand in Denmark and an aggregated map comparing clay-till-thickness distribution within individual PM types. The hydrogeological applicability of the PM concept was tested with a physical-based distributed 3D hydrological model. The aggregated PM map was compared with fracture and redox conditions at 21 field sites to evaluate the PM-type correlation to: (1) till thickness, (2) thickness of the reduced-till zone, and (3) depth to the zone with fracture spacing >1 m The results show that the till thickness is a critical parameter for the formation of fracture networks in clay till, and that fracture density decreases in till thicker than 8-10 m. However, the amount of data is still inadequate for statistically proving the PM concept.

Klint, Knud Erik S.; Nilsson, Bertel; Troldborg, Lars; Jakobsen, Peter Roll

2013-09-01

215

The typology of Irish hard-rock aquifers based on an integrated hydrogeological and geophysical approach  

NASA Astrophysics Data System (ADS)

Groundwater flow in hard-rock aquifers is strongly controlled by the characteristics and distribution of structural heterogeneity. A methodology for catchment-scale characterisation is presented, based on the integration of complementary, multi-scale hydrogeological, geophysical and geological approaches. This was applied to three contrasting catchments underlain by metamorphic rocks in the northern parts of Ireland (Republic of Ireland and Northern Ireland, UK). Cross-validated surface and borehole geophysical investigations confirm the discontinuous overburden, lithological compartmentalisation of the bedrock and important spatial variations of the weathered bedrock profiles at macro-scale. Fracture analysis suggests that the recent (Alpine) tectonic fabric exerts strong control on the internal aquifer structure at meso-scale, which is likely to impact on the anisotropy of aquifer properties. The combination of the interpretation of depth-specific hydraulic-test data with the structural information provided by geophysical tests allows characterisation of the hydrodynamic properties of the identified aquifer units. Regionally, the distribution of hydraulic conductivities can be described by inverse power laws specific to the aquifer litho-type. Observed groundwater flow directions reflect this multi-scale structure. The proposed integrated approach applies widely available investigative tools to identify key dominant structures controlling groundwater flow, characterising the aquifer type for each catchment and resolving the spatial distribution of relevant aquifer units and associated hydrodynamic parameters.

Comte, Jean-Christophe; Cassidy, Rachel; Nitsche, Janka; Ofterdinger, Ulrich; Pilatova, Katarina; Flynn, Raymond

2012-12-01

216

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

SciTech Connect

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

Ojiambo, S. Bwire

1992-01-01

217

Integration Of Borehole Methods For Hydrogeologic Characterization Optimizes Remediation And Monitoring Efforts  

NASA Astrophysics Data System (ADS)

Effective remediation and monitoring requires accurate subsurface characterization. Thorough knowledge regarding the spatial distribution of contaminants and the nature of their migration pathways in the subsurface improves the chances for success of subsequent remediation and monitoring efforts by providing more accurate data for the selection of optimal remedial strategies and monitoring over time. While a variety of borehole based methods for evaluating hydrogeologic properties have been proposed over the last twenty years, the technical degree of success or advancement of the science has not always resulted in the widespread use of the methods employed. Poor understanding about appropriate application of the methods has sometimes hindered utilization when benefits could have been realized. However, of the methods that have been accepted and routinely deployed, there has been demonstrated value of integrating two or more methods for more accurate understanding of the subsurface. A review of numerous methods, their development history, optimal integrated usage, commercialization and industry acceptance will be presented. Methods discussed would include; borehole imaging tools, heat-pulse flowmeter, EM flowmeter, Hydrophysical Logging, colloidal borescope (fixed and scanning), wireline straddle packer, passive diffusion samplers and others

Pedler, W. H.

2009-12-01

218

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

SciTech Connect

Yucca Mountain, in southern Nevada, is being investigated by the US 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 US 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. Shallow infiltration is not discussed in detail in this report because the focus in on three major aspects of the deep unsaturated-zone system: geologic framework, the gaseous-phase system, and the aqueous-phase system. However, because the relation between shallow infiltration and deep percolation is important to an overall understanding of the unsaturated-zone flow system, a summary of infiltration studies conducted to date at Yucca Mountain is provided in the section titled Shallow Infiltration. This report describes results of several Site Characterization Plan studies that were ongoing at the time excavation of the ESF North Ramp began and that continued as excavation proceeded.

Rousseau, J.P.; Kwicklis, E.M.; Gillies, D.C. [eds.

1999-03-01

219

Regional groundwater flow in mountainous terrain: Three-dimensional simulations of topographic and hydrogeologic controls  

USGS Publications Warehouse

This study uses numerical simulations to define the salient controls on regional groundwater flow in 3-D mountainous terrain by systematically varying topographic and hydrogeologic variables. Topography for idealized multiple-basin mountainous terrain is derived from geomatic data and literature values. Water table elevation, controlled by the ratio of recharge to hydraulic conductivity, largely controls the distribution of recharged water into local, regional, and perpendicular flow systems, perpendicular flow being perpendicular to the regional topographic gradient. Both the relative (%) and absolute (m 3/d) values of regional flow and perpendicular flow are examined. The relationship between regional flow and water table elevation is highly nonlinear. With lower water table elevations, relative and absolute regional flow dramatically increase and decrease, respectively, as the water table is lowered further. However, for higher water table elevations above the top of the headwater stream, changes in water table elevation have little effect on regional flow. Local flow predominates in high water table configurations, with regional and perpendicular flow <15% and <10%, respectively, of total recharge in the models tested. Both the relative and the maximum absolute regional flow are directly controlled by the degree of incision of the mountain drainage network; the elevation of mountain ridges is considerably less important. The percentage of the headwater stream with perennial streamflow is a potentially powerful indicator of regional flow in all water table configurations and may be a good indicator of the susceptibility of mountain groundwater systems to increased aridity. Copyright 2008 by the American Geophysical Union.

Gleeson, T.; Manning, A. H.

2008-01-01

220

Analysis of damaging hydrogeological events: the case of the Calabria Region (Southern Italy).  

PubMed

A period of bad weather conditions due to prolonged intense rainfall and strong winds can trigger landslides, floods, secondary floods (accumulation of rain on surfaces with low permeability), and sea storms, causing damage to humans and infrastructure. As a whole, these periods of bad weather and triggered phenomena can be defined as damaging hydrogeological events (DHEs). We define a methodological approach based on seven simple indexes to analyze such events. The indexes describe the return period (T) and trend of rainfall, the extent of hit areas, and the level of damages; they can be considered attributes of georeferenced features and analyzed with GIS techniques. We tested our method in an Italian region frequently hit by DHEs. In a period of 10 years, 747 damaging phenomena (landslides, 43%; floods, 38%) and 94 DHEs have been classified. The road network and housing areas are the most frequently damaged elements, threatened by all types of damaging phenomena. T classes are almost in accordance with the level of damage. These results can be used to outline warning levels for civil protection purposes, to forecast the areas most likely to be hit and the potential ensuing damage, to disseminate information concerning vulnerable areas, and to increase people's awareness of risk. PMID:19034561

Petrucci, O; Polemio, M; Pasqua, A A

2008-11-25

221

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

USGS Publications Warehouse

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.

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

1998-01-01

222

The Geologic and Hydrogeologic Setting of the Waste Isolation Pilot Plant  

SciTech Connect

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.

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

1999-03-04

223

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

PubMed

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

Seaton, William J; Burbey, Thomas J

224

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

NASA Astrophysics Data System (ADS)

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.

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

2012-02-01

225

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

NASA Astrophysics Data System (ADS)

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

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

2008-11-01

226

Model evaluation of the hydrogeology of the Cypress Creek well field : in west-central Florida  

USGS Publications Warehouse

The Cypress Creek well field is being developed to help supply a rapidly growing population in west-central Florida. The ground-water system in the Cypress Creek well-field area consists of a surficial sand aquifer, a semiconfining clay layer ranging from 2 to 25 feet in thickness, and a sequence of carbonate rocks, approximately 1,000 feet thick, called the Floridan aquifer. All recharge to the Floridan aquifer in the local area is derived from the overlying surficial sand aquifer by downward percolation through the semiconfining clay bed. The major proportion of water supplied to municipal wells open to the Floridan aquifer comes from a dolomitic section of the Avon Park Limestone containing two major cavernous zones. The hydrogeology of the well-field area was evaluated by digital model simulation. Model runs were made to analyze sensitivity of the model to variations in selected hydrologic parameters. The model was tested further by attempting to simulate the potentiometric surface of the Floridan aquifer under actual pumping stresses during the January 1976 dry period. (Woodard-USGS).

Ryder, Paul D.

1978-01-01

227

Influence of construction on hydrogeological and environmental conditions in the karst region, eastern Herzegovina, Yugoslavia  

NASA Astrophysics Data System (ADS)

The region of eastern Herzegovina and Dubrovnik coastal belt is one of the hydrogeologically and hydrologically most interesting regions of Yugoslavia karst. The main water course in the region is the Trebišnjica river, the largest sinking river in Europe. All the poljes in the catchment area are temporary flooded, hydrologically separated, and closed karst entities. Enormous quantities of available water are not evenly disturbed neither in the time nor in the space. The Trebišnjica Hydrosystem project uses the basic concept of total water regime organization and its multipurpose utilization. With the construction of seven dams, six artificial reservoirs, six tunnels (with total length, 57 km), and four canals (with total length 74 km) the natural regime of surface and underground waters has been completely changed. As a consequence of water regime disturbance, a lot of changes have been observed in the catchment area: changes in the karst aquifers; local changes of climate conditions; eolic erosion effect; influence on the karst underground and littoral belt; influence on the springs yield; influence on adjacent catchment area; pollution of karst aquifers and influence of storage reservoirs on seismicity—induced seismicity. This article presents influences observed after the first stage of hydrosystem construction.

Milanovi?, Petar

1990-01-01

228

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

SciTech Connect

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).

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

229

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

USGS Publications Warehouse

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.

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

1993-01-01

230

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

USGS Publications Warehouse

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

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

1997-01-01

231

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

USGS Publications Warehouse

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.

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

2008-01-01

232

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

USGS Publications Warehouse

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.

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

2000-01-01

233

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

NASA Astrophysics Data System (ADS)

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.

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

2009-04-01

234

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

USGS Publications Warehouse

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.

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

2002-01-01

235

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

USGS Publications Warehouse

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.

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

2002-01-01

236

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

237

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

SciTech Connect

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.

Quinn, Nigel W.T.

2007-07-15

238

Integrating field and numerical modeling methods for applied urban karst hydrogeology  

NASA Astrophysics Data System (ADS)

Infrastructures constructed on unstable geologic formations are prone to subsidence. Data have been collected in the context of an upgrading project for a highway located beside a river dam constructed on gypsum-bearing formations. Surface water infiltrates upstream of the dam, circulates through the gravel deposits and into the weathered bedrock around and beneath the dam, and exfiltrates downstream into the river. As a result, an extended weathering zone within the bedrock and preferential flow paths within voids and conduits developed as part of a rapidly evolving karst system. Enhanced karstification in the soluble units of the gypsum-bearing formations resulted in subsidence of the dam and the highway. Since 2006, changes in the groundwater flow regime have been investigated by different methods that allowed the evaluation of the long-term performance of the infrastructures. Geological (outcrops, lithostratigraphic information from boreholes), hydrometrical (extensive groundwater monitoring, dye tracer tests) and hydrogeophysical (Electrical Resistivity Tomography, ERT) data were integrated into high-resolution 3-D hydrogeological and 2-D karst evolution models. The applied methods are validated and the sensitivity of relevant parameters governing the processes determined. It could be demonstrated that the applied methods for karst aquifer characterization complement each other. Short-term impacts and long-term developments on system-dynamics and the flow regime could be evaluated. This includes the description of the transient character of the flow regime during and after episodic flood events (surface-groundwater interaction, conduit and diffuse model outflow) as well as the evaluation of time scales for karst evolution. Results allow the optimization of investigation methods for similar subsidence problems, ranging from general measurements and monitoring technologies to tools with predictive utility.

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

2009-07-01

239

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

USGS Publications Warehouse

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.

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

1997-01-01

240

Hydrogeological study for improved nature restoration in dune ecosystems--Kleyne Vlakte case study, Belgium.  

PubMed

In dune slacks a close coupling exists between changes in the hydrology and changes in species composition and vegetation structure. Consequently, there is a need to underpin nature restoration projects not only with ecologically relevant knowledge but also with scientifically sound hydrogeological data. In this paper, this necessity is illustrated through a study of the Flemish Nature Reserve 'The Zwindunes and Zwinpolders' (Belgian coastal plain) as an example. The management plan for the nature reserve suggests rewetting part of it to enhance its ecological value. The groundwater aspect was studied by means of field observations and mathematical modelling. First, fresh water head observation showed a mean groundwater flow from the nature reserve to the adjacent polder. Secondly, groundwater quality was studied with borehole measurements and water samples, resulting in a map of the fresh-salt water distribution and of water types. All available information was then put together in a density dependent groundwater flow model. The aim of this model was the description of current flow and fresh-salt water distribution and to simulate the impact of three possible rewetting scenarios. Rewetting will be accomplished by the infiltration of water in a depression, different lay-outs for which are considered. A zoomed in flow model based on a regional model was used to incorporate both local scale, which is of importance to ecology, and the larger scale, which determines general groundwater flow and fresh-salt water distribution. This modelling indicated differences between scenarios and was used to decide on the best rewetting strategy. PMID:20655140

Vandenbohede, A; Lebbe, L; Adams, R; Cosyns, E; Durinck, P; Zwaenepoel, A

2010-07-22

241

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

USGS Publications Warehouse

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

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

2007-01-01

242

A hydrogeological study of the Nhandugue River, Mozambique - A major groundwater recharge zone  

NASA Astrophysics Data System (ADS)

The Nhandugue River flows over the western margin of the Urema Rift, the southernmost extension of the East African Rift System, and marks the north-western border of Gorongosa National Park, Mozambique. It constitutes one of the major indispensable water resources for the ecosystem that the park protects. Our study focused on the hydrogeological conditions at the western rift margin by resistivity measurements, soil sampling and discharge measurements. The resistivity results suggest that the area is heavily faulted and constitutes a major groundwater recharge zone. East of the rift margin the resistivity indicate that solid gneiss is fractured and weathered, and is overlain by sandstone and alluvial sediments. The top 10-15 m of the alluvial sequence is interpreted as sand. The sand layer extends back to the rift margin thus also covering the gneiss. The sandstone outcrops a few kilometers from the rift margin and dips towards east/south-east. Further into the rift valley, the sand is underlain by lenses of silt and clay on top of sand mixed with finer matter. In the lower end of the investigated area the lenses of silt and clay appears as a more or less continuous layer between the two sand units. The topmost alluvial sand constitutes an unconfined aquifer under which the solid gneiss forms a hydraulic boundary and the fractured gneiss an unconfined aquifer. The sandstone is an unconfined aquifer in the west, becoming semi-confined down dip. The lenses of silt and clay forms an aquitard and the underlying sand mixed with finer matter a semi-confined aquifer. The surface runoff decreases downstream and it is therefore concluded that surface water infiltrates as recharge to the aquifers and moves as groundwater in an east/south-eastward direction.

Arvidsson, K.; Stenberg, L.; Chirindja, F.; Dahlin, T.; Owen, R.; Steinbruch, F.

243

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

NASA Astrophysics Data System (ADS)

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

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

2009-04-01

244

Blocking Moving Window algorithm: Conditioning multiple-point simulations to hydrogeological data  

NASA Astrophysics Data System (ADS)

Connectivity constraints and measurements of state variables contain valuable information on aquifer architecture. Multiple-point (MP) geostatistics allow one to simulate aquifer architectures, presenting a predefined degree of global connectivity. In this context, connectivity data are often disregarded. The conditioning to state variables is usually carried out by minimizing a suitable objective function (i.e., solving an inverse problem). However, the discontinuous nature of lithofacies distributions and of the corresponding objective function discourages the use of traditional sensitivity-based inversion techniques. This work presents the Blocking Moving Window algorithm (BMW), aimed at overcoming these limitations by conditioning MP simulations to hydrogeological data such as connectivity and heads. The BMW evolves iteratively until convergence: (1) MP simulation of lithofacies from geological/geophysical data and connectivity constraints, where only a random portion of the domain is simulated at every iteration (i.e., the blocking moving window, whose size is user-defined); (2) population of hydraulic properties at the intrafacies; (3) simulation of state variables; and (4) acceptance or rejection of the MP simulation depending on the quality of the fit of measured state variables. The outcome is a stack of MP simulations that (1) resemble a prior geological model depicted by a training image, (2) honor lithological data and connectivity constraints, (3) correlate with geophysical data, and (4) fit available measurements of state variables well. We analyze the performance of the algorithm on a 2-D synthetic example. Results show that (1) the size of the blocking moving window controls the behavior of the BMW, (2) conditioning to state variable data enhances dramatically the initial simulation (which accounts for geological/geophysical data only), and (3) connectivity constraints speed up the convergence but do not enhance the stack if the number of iterations is large.

Alcolea, Andres; Renard, Philippe

2010-08-01

245

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

PubMed

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

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

2013-06-07

246

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

SciTech Connect

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.

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

1995-09-01

247

Effects of hydrogeological characteristics on the attenuation of TCE- contaminated groundwater plume in Wonju, Korea  

NASA Astrophysics Data System (ADS)

Key attributes to temporal and seasonal variation of TCE and its daughter products at an industrial complex, Wonju, Korea were evaluated using groundwater monitoring data along with data from field investigations. The purpose of this study is to analyze the hydrogeological characteristics and seasonal variations associated with the plume attenuation of TCE and its daughter products. Study site is underlain by Jurassic biotite granite which is covered by quarternary alluvium. Average hydraulic conductivities of alluvial layer and bed rock are 2.4*10-3 and 2.0*10-4 cm/sec, respectively. The alluvial layer acts as a main layer for TCE contaminated groundwater flow. Average annual rainfall in this study area is 1,414 mm/year and over 65% of annual precipitation is concentrated in July, August and September. Seasonal variation of TCE contaminant plume shape near the source area and downgradient area are different depending on the surface recharge characteristics. The downgradient area is not much affected by seasonal rainfalls, but TCE contaminant concentration in the source area is greatly affected by the seasonal rainfalls. The water table fluctuation at the source area was maximally 1.95 m but the downgradient at industrial complex area was 0.9 m during concentrated rainfall events. General tendency of TCE contaminant concentrations at source zone was highly fluctuated and temporally increased due to rainfall events. As a result, due to the limited recharge and time-lag of the impact of precipitation in summer season, the TCE contaminant plume distribution and the impact of seasonal effect diminish as the distance from the source area increases. Keywords : TCE, recharge, precipitation, plume attenuation, seasonal variation

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

2010-12-01

248

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

NASA Astrophysics Data System (ADS)

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

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

2005-01-01

249

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

USGS Publications Warehouse

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

Edited by Minor, Scott A.

2006-01-01

250

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

USGS Publications Warehouse

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)

Roberts, R. S.

1987-01-01

251

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

SciTech Connect

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.

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

1987-07-01

252

Hydrogeology of karst aquifer systems in SW Turkey and an assessment of water quality and contamination problems  

NASA Astrophysics Data System (ADS)

The aim of this research is to determine the relationship between groundwater flow and water quality of different ground and surface water basins in the southwest Turkey. In addition, groundwater vulnerability is assessed taking into consideration groundwater flow and quality. The autochthonous Beydaglari limestone is the major karstic aquifer in the region. According to the groundwater level map of alluvium aquifers in the basins, groundwater discharge toward the carbonate aquifer is direct and indirect. The hydrogeological connection between ground and surface water basins occurs via the karstic aquifer located at the bottom of the alluvium bottom. In Egirdir lake, water also discharges in the karstic aquifer via karstic sinkholes at the western border of the lake. In the research area, general groundwater discharge is toward the Mediterranean Sea by means of autochthonous carbonate system, according to hydrogeological investigations, research of lineament and hydraulic conductivities. This result is supported by the locations of lineaments and shore springs discharging from the limestone. In addition, spreading of contaminants via karstic aquifer to great distance has been clearly identified.

Davraz, Aysen; Karaguzel, Remzi; Soyaslan, Iskender; Sener, Erhan; Seyman, Fatma; Sener, Sehnaz

2009-09-01

253

Preliminary hydrogeologic evaluation of the Cincinnati Arch region for underground high-level radioactive waste disposal, Indiana, Kentucky , and Ohio  

USGS Publications Warehouse

Preliminary interpretation of available hydrogeologic data suggests that some areas underlying eastern Indiana, north-central Kentucky, and western Ohio might be worthy of further study regarding the disposal of high-level radioactive waste in Precambrian crystalline rocks buried beneath Paleozoic sedimentary rocks in the area. The data indicate that (1) largest areas of deepest potential burial and thickest sedimentary rock cover occur in eastern Indiana; (2) highest concentrations of dissolved solids in the basal sandstone aquifer, suggesting the most restricted circulation, are found in the southern part of the area near the Kentucky-Ohio State line and in southeastern Indiana; (3) largest areas of lowest porosity in the basal sandstone aquifer, low porosity taken as an indicator of the lowest groundwater flow velocity and contaminant migration, are found in northeastern Indiana and northwestern Ohio, central and southeastern Indiana, and central Kentucky; (4) the thickest confining units that directly overlie the basal sandstone aquifer are found in central Kentucky and eastern Indiana where their thickness exceeds 500 ft; (5) steeply dipping faults that form potential hydraulic connections between crystalline rock, the basal sandstone aquifer, and the freshwater circulation system occur on the boundaries of the study area mainly in central Kentucky and central Indiana. Collectively, these data indicate that the hydrogeology of the sedimentary rocks in the western part of the study area is more favorably suited than that in the remainder of the area for the application of the buried crystalline-rock concept. (USGS)

Lloyd, O. B.; Davis, R. W.

1989-01-01

254

Hydrogeologic Assessment of the 4-S Land and Cattle CompanyRanch  

SciTech Connect

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.

Quinn, Nigel W.T.

2006-04-10

255

Sensitivity analysis of hydrogeological parameters affecting groundwater storage change caused by sea level rise  

NASA Astrophysics Data System (ADS)

Sea level rise, which is one of the representative phenomena of climate changes caused by global warming, can affect groundwater system. The rising trend of the sea level caused by the global warming is reported to be about 3 mm/year for the most recent 10 year average (IPCC, 2007). The rate of sea level rise around the Korean peninsula is reported to be 2.30±2.22 mm/yr during the 1960-1999 period (Cho, 2002) and 2.16±1.77 mm/yr (Kim et al., 2009) during the 1968-2007 period. Both of these rates are faster than the 1.8±0.5 mm/yr global average for the similar 1961-2003 period (IPCC, 2007). In this study, we analyzed changes in the groundwater environment affected by the sea level rise by using an analytical methodology. We tried to find the most effective parameters of groundwater amount change in order to estimate the change in fresh water amount in coastal groundwater. A hypothetical island model of a cylindrical shape in considered. The groundwater storage change is bi-directional as the sea level rises according to the natural and hydrogeological conditions. Analysis of the computation results shows that topographic slope and hydraulic conductivity are the most sensitive factors. The contributions of the groundwater recharge rate and the thickness of aquifer below sea level are relatively less effective. In the island with steep seashore slopes larger than 1~2 degrees or so, the storage amount of fresh water in a coastal area increases as sea level rises. On the other hand, when sea level drops, the storage amount decreases. This is because the groundwater level also rises with the rising sea level in steep seashores. For relatively flat seashores, where the slope is smaller than around 1-2 degrees, the storage amount of coastal fresh water decreases when the sea level rises because the area flooded by the rising sea water is increased. The volume of aquifer fresh water in this circumstance is greatly reduced in proportion to the flooded area with the sea level rising. Since relatively flat seashores where the slope is less than 1-2 degrees are much more common in Korea, it is expected that the quantity of fresh groundwater storage in most of the coastal region in Korea will be greatly reduced with sea level rise. Acknowledgement: This study is financially supported by BK21.

Shin, J.; Kim, K.-H.; Lee, K.-K.

2012-04-01

256

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

NASA Astrophysics Data System (ADS)

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

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

2006-12-01

257

Application of GPR and seismic methods in landslides investigation and determination of hydrogeological conditions  

NASA Astrophysics Data System (ADS)

Ground Penetrating Radar (GPR) belongs to non-invasive geophysical methods which use an artificially induced electromagnetic field as the way for inspection. GPR is applied not only to recognition of shallow geological structure but also to archeological studies. The basic assumption of the applicability of GPR is the existance of a distinct boundary between two lithological horizons defined by a change in permittivity values, which results in a change in electromagnetic wave velocity. For that reason this method is used to locate empty spaces and saturated zones. The purpose of this measurements was to determine the details of the sliding body, including the thickness and lateral extension of the landslide material, the depth of the sliding surface and water content of the subsurface. What is more correlation between GPR and seismic methods was searched. Studied area was located in the Southern part of Poland. Geological structure is characteristic for Carpathian flysch - overlaying claystones, shales and sandstones. Measurements were carried out using GPR equipment from the Swedish company Mala Geoscience. Due to the required depth range and resolution unshielded antennas with frequencies from 25 MHz to 200 MHz were used. Profiles were traced parallel to the landslide axis. Following forms of GPR survey were applied: CO (common offset), CMP (common mid point), WARR (wide-angle reflection-refraction). Modeling attempt electromagnetic field distribution in the medium was undertaken to select the most appropriate measurement parameters and to improve the interpretation. Programme GPRMax2D v. 2.0 was used to create models. The GPR numerical analysis uses the finite - difference time - domain method (FDTD). The FDTD approach to the numerical solution of Maxwell's equations consist of discretization both the space and the time continua. Due to geological structure (presence of low resistivity clays and shales) attenuation of electromagnetic wave was high. In order to verify GPR interpretation seismic measurements was performed. The basic assumption of the applicability of seismic methods is the existance of a distinct boundary between two lithological horizons defined by a change in material density and elastic modulus, which results in an increase or a decrase in wave velocity. Seismic refraction and MASW (multichannel analysis of surface waves) were the main methods. Geophones with frequencies 4 Hz and 10 Hz were used. Topographical variations were included during interpretation. It is possible to correlate GPR and seismic results especially during localization of water saturation zones. All applied methods gave also satisfactory results in recognition of the hydrogeological conditions.

Czaja, Klaudia; Matu?a, Rafa?

2013-04-01

258

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

NASA Astrophysics Data System (ADS)

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.

Dapo, Almin; Pribicevic, Bosko

2013-04-01

259

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

USGS Publications Warehouse

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

Meyer, Frederick W.

1989-01-01

260

Hydrogeologic reconnaissance of the Mekong Delta in South Vietnam and Cambodia  

USGS Publications Warehouse

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.

Anderson, Henry R.

1978-01-01

261

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

NASA Astrophysics Data System (ADS)

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.

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

2009-04-01

262

Hydrogeology of the regional aquifer near Flagstaff, Arizona, 1994-97  

USGS Publications Warehouse

Sandstones, siltstones, and limestones that are Pennsylvanian to Permian in age underlie the southern part of the Colorado Plateau near Flagstaff, Arizona, and contain a complex regional aquifer that has become increasingly important as a source of water for domestic, municipal, and recreational uses. Ground-water flow in the regional aquifer is poorly understood in this area because (1) depth of the aquifer limits exploratory drilling and testing and (2) the geologic structure increases the complexity of the aquifer characteristics and the ground-water flow system. Four methods were used to improve the understanding of the hydrogeology of the regional aquifer near Flagstaff. Remote-sensing techniques and geologic mapping provided data to identify many structural features that indicate a more complex structural environment and history than previously realized. Data from surface-geophysical techniques that included ground-penetrating radar, seismic reflection and seismic refraction, and square-array resistivity, verified that some of the geologic structures expressed at land surface propagate deep into the subsurface and through the principal water-bearing zones of the regional aquifer at near-vertical angles. A well and spring inventory, borehole-geophysical methods, and well and aquifer tests provided additional information relating aquifer and ground-water flow characteristics to geologic structure. Water-chemistry data, which included major ion, nutrient, trace-element, and radioactive and stable-isotope analyses, provided an independent means of verifying the hydrogeologic characteristics of the aquifer and were used to determine recharge and discharge areas, ground-water movement, and ground-water age. Ground-water recharge occurs throughout the area but is greatest at higher altitudes where precipitation is greater and in areas where heavily fractured rock units of the aquifer are exposed. The estimated annual average recharge to the regional aquifer in the study area is about 290,000 acre-feet. Ground water flows laterally and vertically through pore spaces in the rock and along faults and other fractures from high-altitude areas in the southern part of the study area to regional drains north of the study area along the Little Colorado and Colorado Rivers, and to drains south of the study area along Oak Creek and the Verde Valley. Ground-water discharge in these areas?about 400,000 acre-feet per year?exceeds the annual recharge to the aquifer in the Flagstaff area, but ground water from areas outside the study area contributes to this discharge as well. The saturated thickness of the regional aquifer averages about 1,200 feet, and the amount of water in storage could be as much as 4,800,000 acre-feet, or about 10 percent of the total volume of the aquifer. The quality of water in the regional aquifer in terms of dissolved-solids concentrations is good for most uses throughout the area. Dissolved-solids concentrations generally are less than 500 milligrams per liter. Water in the regional aquifer is primarily a calcium magnesium bicarbonate type. In some areas near the Rio de Flag, the water has significant nitrate and chloride components, which indicate direct recharge in these areas from the Rio de Flag. Oxygen and deuterium data indicate a common recharge source for water in the aquifer and that some sites receive recharge from surface waters where evaporation has occurred. Estimated carbon-14 ages and tritium activities indicate ground-water ages from less than 200 years in the Lake Mary area to more than 5,000 years in the Wupatki area. The regional aquifer is heterogeneous and anisotrophic and has a complex ground-water flow system. The most productive water-bearing material tends to be fine- to medium-grained sandstones, and ground-water flow and potential well yields are related to geologic structure. Fracturing associated with structural deformation increases recharge locally and also increases the potential for

Bills, Donald J.; Truini, Margot; Flynn, Marilyn E.; Pierce, Herbert A.; Catchings, Rufus D.; Rymer, Michael J.

2000-01-01

263

Prevention of Hydrogeological Risk: The Time and Space Distribution of Catastrophic Events In A Selected Coastal Area of The Campanian Region, Italy  

Microsoft Academic Search

Hydrogeological phenomena induced by rainstorm events occurring along a narrow coastal area of about 20 km, that lies between Amalfi and Salerno (Salerno Gulf), have been studied in detail. Several case histories have been reconstructed, since the XIX century, through the analysis of a wide variety of published and unpublished histor- ical and current sources, including scientific papers, archival and

E. Esposito; S. Porfido; C. Violante; F. Alaia

2002-01-01

264

Calendar year 1994 groundwater quality report for the Bear Creek hydrogeologic regime, Y-12 Plant, Oak Ridge, Tennessee. 1994 Groundwater quality data interpretations and proposed program modifications  

SciTech Connect

This groundwater quality report (GWQR) contains an evaluation of the groundwater quality data obtained during the 1994 calendar year (CY) at several hazardous and non-hazardous waste management facilities at the US Department of Energy (DOE) Y-12 Plant. These sites lie in Bear Creek Valley (BCV) west of the Y-12 Plant within the boundaries of the Bear Creek Hydrogeologic Regime which is one of three hydrogeologic regimes defined for the purposes of groundwater quality monitoring. The Environmental Management Department manages the groundwater monitoring activities under the auspices of the Y-12 Plant Groundwater Protection Program (GWPP). The purpose of the GWPP is to characterize the hydrogeology and to monitor groundwater quality at the Y-12 Plant and surrounding area to protect local groundwater resources. The annual GWQR for the Bear Creek Regime is completed in two parts. Part 1 consists primarily of data appendices and serves as a reference for the groundwater quality data obtained each CY. Part 2 (this report) contains an evaluation of the data with respect to regime-wide groundwater quality, summarizes the status and findings of ongoing hydrogeologic studies, describes changes in monitoring priorities, and presents planned modifications to the groundwater sampling and analysis activities.

NONE

1995-10-01

265

The deep hydrogeologic flow system underlying the Oak Ridge Reservation -- Assessing the potential for active groundwater flow and origin of the brine  

Microsoft Academic Search

The deep hydrogeologic system underlying the Oak Ridge Reservation (ORR) contains contaminants such as radionuclides, heavy metals, nitrates, and organic compounds. The groundwater in the deep system is saline and has been considered to be stagnant in previous studies. This study was designed to address the following questions: is groundwater in the deep system stagnant; is contaminant migration controlled by

R. Nativ; A. Halleran; A. Hunley

1997-01-01

266

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

USGS Publications Warehouse

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

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

2013-01-01

267

Integrated Hydrogeologic Framework Study in Spring Valley, Nevada Using Audiomagnetelluric, Gravity, Magnetic and Borehole Data  

NASA Astrophysics Data System (ADS)

Geophysical surveys were undertaken to identify carbonates, range-front faults, basin stratigraphy, and site drill holes within basins of eastern Nevada. Defining the distribution of basin-fill deposits and their association with the carbonate-rock aquifer system that underlies this region is important for assessing ground-water resources. Regional north-trending structures are a primary structural control on the hydrogeology of the valleys in eastern Nevada. In order to identify significant subsurface structures, audiomagnetotelluric (AMT) data and resulting models were analyzed together with potential field data and geophysical and geological borehole logs in Spring Valley, NV. The AMT method is a valuable tool for estimating electrical resistivity of the earth over depth ranges from a few meters to less than one kilometer. We collected AMT sounding data at 200m intervals along three profiles in southern Spring Valley using a Geometrics Stratagem EH4 system, four-channel, tensor system recording in the range of 10 to 92,000 Hz. To augment the low signal in the natural field, a transmitter of two horizontal-magnetic dipoles was used from 1,000 to 70,000 Hz. Profile A extends 12.6 km from the Fortification Range on the west across southern Spring Valley to the southern Snake Range in the east. Two shorter (~ 2 km) profiles span the margins of the Fortification Range and the Snake Range to the south of Profile A. Data were recorded with the electric field (E) parallel and perpendicular to the N-S regional geological strike direction. Ground magnetic data were collected along two of the profiles and gravity data were collected both regionally as well as in detail along the profiles at 200-400m station spacing. Borehole data, including both lithological and geophysical logs extending 350 m and 500 m below the surface, were available from two water monitoring and testing wells along our AMT profiles Two-dimensional, inverse models were computed from the E perpendicular mode data using a conjugate gradient, finite-difference method to test dimensionality of the structure, resolution and the depth of investigation. Our preferred AMT models show detailed structure within the alluvial basin. Interpretation of the AMT models, along with the other geophysical data, defines several faults, some of which may influence ground-water flow in the valley, as well as the underlying Paleozoic carbonate, and volcanic and clastic rocks within the basin. Basin thickness estimates derived from gravity data agree with the base of the volcanic rocks imaged with the AMT data. Fine-grained (clay-rich) material can be differentiated within the basin fill. Comparison of AMT models with borehole and lithology data help constrain our interpretation, yet also unveil limitations of both datasets.

McPhee, D. K.; Pellerin, L.

2011-12-01

268

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

NASA Astrophysics Data System (ADS)

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

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

269

Shallow groundwater denitrification capacity at three contrasting hydrogeological environments in Ireland  

NASA Astrophysics Data System (ADS)

Denitrification may be regarded as the dominant nitrate removal or attenuation process in shallow groundwater. A major concern arising from the denitrification process is that it not only serves as a natural pathway for excess NO3- removal but its intermediate product, N2O, is a potent greenhouse gas. A groundwater monitoring network was established on grazed grassland at research farms at Johnstown Castle (JC) and Solohead (SH) on tillage at Oak Park (OP) in Ireland, to investigate the denitrification capacity and N2O:(N2O+N2) ratio within the shallow groundwater zone. The geology of this zone at the 3 sites was i) JC: sand and gravel intermixed with clay, ii) SH: silt and gravel intermixed with dense clay and iii) OP: dense gravel with interbedded clays. Average groundwater table was respectively 3.2, 2.4 and 4.0 m below ground level. Ten piezometers of 50 mm ID with 2 m screen sections were installed at 3.5-6.0 m below ground level using a rotary air drilling method at the three sites. Groundwater sampling was carried out monthly for 6 months (February to July, 2009) using a bladder pump following the USEPA low flow sampling procedures. Dissolved groundwater N2O was separated by degassing groundwater in a sealed serum bottle (160ml) using high purity He (water:He = 3:1) and the collected headspace equilibrium gas was analyzed on a Varian gas chromatograph. The N2/Ar ratio, measured using a Membrane Inlet Mass Spectrometer, was used to estimate the denitrified N2 concentrations. The mean NO3-N concentrations were 7.0, 2.5 and 11.0 mg L-1 in JC, SH and OP, respectively. Ground water dissolved N2O concentrations ranged from 0.01 to 0.05, 0.01 to 0.06 and 0.002 to 0.06 mg L-1, with corresponding mean values of 0.03, 0.02, 0.02 mg N.L-1 in JC, SH and OP, respectively. The mean values for total denitrification (N2O+N2) were 1.94, 1.03 and 0.38 mg N.L-1, which accounted for 22, 29 and 3% losses of total NO3- -N in JC, SH and OP, respectively. The higher denitrification measured on the grassland compared to tillage is most likely related to the hydrogeological conditions e.g. DOC, DO and redox-potential rather than land-use. More importantly, the mean N2O:N2O+N2 ratios, being 0.01, 0.02 and 0.05, respectively in JC, SH and OP indicated that 95-99% of total denitrification was molecular N2 (98-99% in grassland and 95% in tillage farm). With respect to temporal changes, denitrification losses were higher in May in grassland systems and in April in tillage farming systems. Shallow groundwater denitrification appeared to be an important process in reducing NO3- , with low N2O concentrations indicating low losses of this greenhouse gas to the atmosphere upon discharging to surface water.

Mofizur Rahman Jahangir, Mohammad; Johnston, Paul; Khalil, Mohammad Ibrahim; Richards, Karl

2010-05-01

270

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

NASA Astrophysics Data System (ADS)

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.

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

2008-12-01

271

Hydrogeology and the distribution of salinity in the Floridan aquifer system, Palm Beach County, Florida  

USGS Publications Warehouse

The virtually untapped Floridan aquifer system is considered to be a supplemental source of water for public use in the highly populated coastal area of Palm Beach County. A recent study was conducted to delineate the distribution of salinity in relation to the local hydrogeology and assess the potential processes that might control (or have affected) the distribution of salinity in the Floridan aquifer system. The Floridan aquifer system in the study area consists of the Upper Floridan aquifer, middle confining unit, and Lower Floridan aquifer and ranges in age from Paleocene to Oligocene. Included at its top is part of a lowermost Hawthorn Group unit referred to as the basal Hawthorn unit. The thickness of this basal unit is variable, ranging from about 30 to 355 feet; areas where this unit is thick were paleotopographic lows during deposition of the unit. The uppermost permeable zones in the Upper Floridan aquifer occur in close association with an unconformity at the base of the Hawthorn Group; however, the highest of these zones can be up in the basal unit. A dolomite unit of Eocene age generally marks the top of the Lower Floridan aquifer, but the top of this dolomite unit has a considerable altitude range: from about 1,200 to 2,300 feet below sea level. Additionally, where the dolomite unit is thick, its top is high and the middle confining unit of the Floridan aquifer system, as normally defined, probably is not present. An upper zone of brackish water and a lower zone of water with salinity similar to that of seawater (saline-water zone) are present in the Floridan aquifer system. The brackish-water and saline-water zones are separated by a transition zone (typically 100 to 200 feet thick) in which salinity rapidly increases with depth. The transition zone was defined by using a salinity of 10,000 mg/L (milligrams per liter) of dissolved-solids concentration (about 5,240 mg/L of chloride concentration) at its top and 35,000 mg/L of dissolved-solids concentration (about 18,900 mg/L of chloride concentration) at its base. The base of the brackish-water zone and the top of the saline-water zone were approximately determined mostly by means of resistivity geophysical logs. The base of the brackish-water zone in the study area ranges from about 1,600 feet below sea level near the coast to almost 2,200 feet below sea level in extreme southwestern Palm Beach County. In an area that is peripheral to Lake Okeechobee, the boundary unexpectedly rises to perhaps as shallow as 1,800 feet below sea level. In an upper interval of the brackish-water zone within the Upper Floridan aquifer, chloride concentration of water ranges from 490 to 8,000 mg/L. Chloride concentration correlates with the altitude of the basal contact of the Hawthorn Group, with concentration increasing as the altitude of this contact decreases. Several areas of anomalous salinity where chloride concentration in this upper interval is greater than 3,000 mg/L occur near the coast. In most of these areas, salinity was found to decrease with depth from the upper interval to a lower interval within the brackish-water zone: a reversal of the normal salinity trend within the zone. These areas are also characterized by an anomalously low altitude of the base of the brackish-water zone, and a much greater thickness of the transition zone than normal. These anomalies could be the result of seawater preferentially invading zones of higher permeability in the Upper Floridan aquifer during Pleistocene high stands of sea level and incomplete flushing of this high salinity water by the present-day flow system.

Reese, R. S.; Memberg, S. J.

2000-01-01

272

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

NASA Astrophysics Data System (ADS)

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).

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

2013-04-01

273

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

USGS Publications Warehouse

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.

McSwain, Kristen B.

1999-01-01

274

Pesticides in Ground Water in Selected Agricultural Land-Use Areas and Hydrogeologic Settings in Pennsylvania, 2003-07  

USGS Publications Warehouse

This report was prepared by the U.S. Geological Survey (USGS) in cooperation with the Pennsylvania Department of Agriculture (PDA) as part of the Pennsylvania Pesticides and Ground Water Strategy (PPGWS). Monitoring data and extensive quality-assurance data on the occurrence of pesticides in ground water during 2003-07 are presented and evaluated; decreases in the land area used for agriculture and corresponding changes in the use of pesticides also are documented. In the Pennsylvania ground waters assessed since 2003, concentrations of pesticides did not exceed any maximum contaminant or health advisory levels established by the U.S. Environmental Protection Agency; PPGWS actions are invoked by the PDA at fractions of these levels and were needed only in areas designated by the PDA for special ground-water protection. Previous investigations through 1998 of pesticides in Pennsylvania ground water identified land use, as a surrogate for pesticide use, and rock type of the aquifer combined with physiography as key hydrogeologic setting variables for understanding aquifer vulnerability to contamination and the common occurrence of atrazine and metolachlor in ground water. Of 20 major hydrogeologic settings in a framework established in 1999 for pesticide monitoring in Pennsylvania, 9 were identified as priorities for data collection in order to change the monitoring status from 'inadequate' to 'adequate' for the PPGWS. Agricultural and forested land-use areas are decreasing because of urban and suburban growth. In the nine hydrogeologic settings evaluated using 1992 and 2001 data, decreases of up to 12 percent for agricultural land and 10 percent for forested land corresponded to increases of up to 11 percent for urban land. Changes in agricultural pesticide use were computed from crop data. For example, from 1996 to 2004-05, atrazine use declined by about 15 percent to 1,314,000 lb/yr (pounds per year) and metolachlor use increased by about 20 percent to 895,000 lb/yr; these compounds are the two most-used agricultural pesticides statewide. In 2003-07, a baseline assessment of pesticides was conducted in five of nine hydrogeologic settings with inadequate monitoring data - the Blue Ridge crystalline and Triassic Lowland siliciclastic, Eastern Lake surficial, Devonian-Silurian carbonate, Great Valley siliciclastic, and Northeastern Glaciated surficial settings. Between 20 and 30 wells in each setting were monitored. Of the 126 wells sampled, 96 well-water samples were analyzed for at least 52 pesticide compounds at the USGS National Water Quality Laboratory (NWQL) using a method with a minimum reporting level (MRL) at or above 0.002 ug/L (micrograms per liter). Of the 96 well waters analyzed by NWQL, 43 had measureable concentrations of one or more pesticides. Atrazine and (or) deethylatrazine (CIAT), a degradation product of atrazine, were reported at or above the MRL in 39 of the 43 well waters. Neither atrazine nor CIAT were reported at concentrations exceeding 0.10 ug/L; all measured concentrations in these five settings were below PPGWS action levels. Metolachlor was present in 7 of the 43 well waters with measureable concentrations of 1 or more pesticides; however, concentrations were below the MRL. The other 30 samples (10 of 20 wells in the Blue Ridge crystalline and Triassic Lowland siliciclastic setting and all 20 wells in the Eastern Lake surficial setting) were analyzed for at least 19 pesticide compounds at the Pennsylvania Department of Environmental Protection Laboratory (PADEPL); the PADEPL reported no concentrations of pesticides at or above an MRL of 0.10 ug/L. Statistical tests using the NWQL analytical results showed correlations between pesticide occurrence and two indicators of water-quality degradation - the occurrence of total coliform bacteria and nitrate concentration. A 2 x 2 contingency-table test indicated a relation between presence or absence of atrazine or metolachlor and presence or a

Loper, Connie A.; Breen, Kevin J.; Zimmerman, Tammy M.; Clune, John W.

2009-01-01

275

Hydrogeologic controls on ground-water and contaminant discharge to the Columbia River near the Hanford Townsite  

SciTech Connect

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.

Luttrell, S.P.; Newcomer, D.R.; Teel, S.S.; Vermeul, V.R.

1992-11-01

276

Description and hydrogeologic implications of cored sedimentary material from the 1975 drilling program at the radioactive waste management complex, Idaho  

USGS Publications Warehouse

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)

Rightmire, C. T.

1984-01-01

277

Lineament Mapping for Hydrogeological Characterization of Volcanic Terrains Using Products Derived from DEMs, Radar, Landsat and Aster Imagery  

NASA Astrophysics Data System (ADS)

Remote sensing techniques can be used in the characterization of landscapes for assessing groundwater resources. Expressions of the subsurface geological conditions, such as faulting, qualitative proximity of the groundwater table to the surface, and changes in bedrock geology, can be inferred from satellite imagery. Products obtained from satellite imagery can identify areas of higher potential for more detailed water resources exploration activities, such as surface geophysics, hydrochemistry and hydraulic analysis to be focus on these priority areas. Lineament mapping has been the most common application of remotely sensed imagery to delineate places for geophysical studies and well drilling. A remote sensing-based protocol is presented for characterizing fracture networks, discontinuities and boundaries of local and regional aquifer systems, and to evaluate their control on natural hydrological behavior and well yields in volcanic aquifers. The protocol is tested using satellite imagery (RADARSAT-1, Landsat TM and ETM+, Aster) and two DEMs (30- and 90-m spatial resolutions) applied to the Quito Aquifer System (QAS). The aquifer is located in the Central Inter-Andean Valley of Ecuador, a region affected by active volcanism and faulting and characterized by basins filled with series of volcanic deposits and primary and reworked sedimentary rocks. Coincidence analysis was applied after initial processing and interpretation to obtain a lineament map of the study areas. By combining our results with those from previous geological studies and hydrogeological data, a pattern of fracturing that is affecting the hydrogeology of the QAS can be distinguished and an improved understanding of the regional flow systems was gained.

Rios-Sanchez, M.; Gierke, J. S.; Muñoz-Martínez, T.

2010-12-01

278

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

USGS Publications Warehouse

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/

Bartolino, James R.; Adkins, Candice B.

2012-01-01

279

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

NASA Astrophysics Data System (ADS)

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. Une étude hydrogéologique a été entreprise sur le bassin versant de Zenako-Argaka, près Hagere Selam en Tigray, Ethiopie du Nord, pendant la saison des pluies 2006. Une carte géologique a été dressée sur la base de relevés géophysiques et d’observations de terrain et une zone fracturée localisée au Nord-Ouest du bassin. Un aquifère perché a été découvert dans la série de trapps basaltiques, au dessus des grès latéritisés du Aram Aradam supérieur. Une carte de cet aquifère a été dressée. La variation du niveau de l’eau durant la période de mesure a été au minimum 4.5 m. La variation du flux de base pour l’ensemble du bassin pendant la période de mesure était comprise entre 12 et 276 m3/jour. Un modèle d’écoulement a été établi avec Visual MODFLOW, indiquant une direction générale d’écoulement vers le Sud, et montrant que les chenaux ont une influence limitée sur l’écoulement de l’aquifère. Le bilan sol eau établi pour la période 1995-2006 montre le rôle important de la distribution des précipitations dans le temps. Bien que Hagere Selam ait reçu quelques 724 mm d’eau par an durant cette période, la forte variation saisonnière des précipitations fait qu’il y a eu un déficit de précipitation 10 mois par an en moyenne. Se llevó a cabo una investigación hidrogeológica en la de Cuenca Zenako-Argaka, cerca de Hagere Selam en Tigray, en Etiopía del Norte, durante la estación lluviosa de 2006. Se produjo un mapa geológico a través de mediciones geofísicas y observaciones de campo, y se identificó una zona de fractura en el noroeste de la cuenca. Se encontró una capa freática colgada dentro de las series de Trap Basalt, por encima de las areniscas Aram Aradam laterizadas. Se compiló un mapa de esta capa freática. Las variaciones del nivel freático durante el período de medición fue de por lo menos 4.5 m. La variación en el flujo de base para la totalidad de la cuenca durante el período de medición fue entre 12 y 276 m3/día. Se desarrolló un modelo de flujo de agua subterránea usando Visual MODFLOW, que indica que la dirección general de flujo es hacia el sur, e ilustra que los cursos de agua tienen solamente una influencia limitada sobre el flujo subterráneo. Se calculó el balance de agua del suelo para el período 1995-2006, lo cual mostró la influencia importante de la distribución de la lluvia en el tiempo. Aunque Hagere Selam recibió alrededor de 724 mm de lluvia por año durante este período, la fuerte variación estacional en la precipitación significó un promedio de déficit de agua durante 10 meses por año. Foi realizado um estudo hidrogeológico na bacia hidrográfica de Zenako-Argaka, perto de Hagere Selam, em Tigray, norte da Etiópia, durante a época das chuvas de 2006. Produziu-se um mapa geológico com base em medições geofísicas e observações de campo

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

2010-12-01

280

Hydrogeology and the distribution of salinity in the Floridan Aquifer system, southwestern Florida  

USGS Publications Warehouse

A study was conducted to establish a detailed hydrogeologic framework in the complex Floridan aquifer system of southwestern Florida, and to evaluate and relate the distribution of salinity found in this system. The Floridan aquifer system consists of the Upper Floridan aquifer, middle confining unit, and Lower Floridan aquifer. The Upper Floridan aquifer extends into a basal unit of the Hawthorn Group; however, a regional unconformity present at the base of this unit generally marks the top of the Floridan aquifer system, as it does in the rest of southern Florida. The basal Hawthorn unit, which is defined at its top by a correlative marker unit, ranges in thickness from 120 to 460 feet. Paleotopography present prior to deposition of the basal Hawthorn unit, which resulted at least in part from erosion, is believed to have caused some of this variation in thickness. However, in some areas where the basal Hawthorn unit is thick, particularly in Lee County, depositional buildup created paleotopographic highs at the top of the unit. In these areas, permeable limestone zones are present in the unit, giving the unit a high transmissivity. In most of the study area, the Floridan aquifer system can be divided into a brackish-water zone, a salinity transition zone, and a saline-water zone. The brackish-water zone contains water with a dissolved-solids concentration of less than 10,000 milligrams per liter. The saline-water zone has a dissolved-solids concentration of at least 35,000 milligrams per liter and a salinity similar to that of seawater. The salinity transition zone that separates these two zones is usually 150 feet or less in thickness. The altitude of the base of the brackish-water zone was mapped primarily using geophysical logs; it ranges from as shallow as 565 feet below sea level along the coast to almost 2,200 feet below sea level inland. This mapping indicated that the boundary represents a salinity interface, the depth of which is controlled by head in the brackish-water zone. Chloride concentrations in the upper part of the brackish-water zone range from 400 to 4,000 milligrams per liter. A large area of relatively low salinity in north-central Collier County and to the northwest, as defined by a 1,200-milligram-per-liter chloride-concentration line, coincides with a high area on the basal contact of the Hawthorn Group. As this contact dips away from this high area to central Hendry and southwestern Collier Counties, chloride concentration increases to 2,000 milligrams per liter or greater. However, the increase in salinity in these areas occurs only in the basal Hawthorn unit or Suwannee Limestone, but not in deeper units. In central Hendry County, the increase occurs only in the basal Hawthorn unit in an area where the unit is well developed and thick. These areas of higher salinity could have resulted from the influx of seawater from southwestern Collier County into zones of higher permeability in the Upper Floridan aquifer during high sea-level stands. The influx may only have occurred in structurally low areas and may have experienced incomplete flushing subsequently by the modern freshwater flow system. In an area in north-central Collier County, the altitude of the base of the brackish-water zone is anomalously deep given the position of this area relative to the coast. In this area, the base extends as deep as 2,090 feet below sea level, and the salinity transition zone is not present or is poorly defined. The origin of this anomalous area is interpreted to be related to the development of a unit containing thick dolomite and evaporite beds high in the middle confining unit of the Floridan aquifer system. The top of this dolomite-evaporite unit, which probably has very low permeability, occurs at the base of the brackish-water zone in this area. The axis of a high area mapped at the top of the unit trends to the northwest from central Collier County into north-central Lee County. This axis parallels and lie

Reese, R. S.

2000-01-01

281

Hydrogeology and simulation of ground-water flow at Superfund-site wells G and H, Woburn, Massachusetts. Water Resources Investigation  

SciTech Connect

The area around wells G and H, two former public-supply wells for the city of Woburn, Massachusetts and currently designated as a U.S. Environmental Protection Agency Superfund site, was the focus of intensive hydrogeologic investigations from 1983 to 1988. The U.S. Geological Survey has provided assistance to the U.S. Environmental Protection Agency for the site since 1985. The report includes hydrogeologic information and describes a three-dimensional, digital ground-water-flow model that was designed and calibrated by the U.S. Geological Survey for use by the U.S. Environmental Protection Agency to evaluate alternative pumping scenarios in developing an aquifer cleanup strategy.

de Lima, V.; Olimpio, J.C.

1990-01-01

282

Relations of hydrogeologic factors, groundwater reduction-oxidation conditions, and temporal and spatial distributions of nitrate, Central-Eastside San Joaquin Valley, California, USA  

Microsoft Academic Search

In a 2,700-km2 area in the eastern San Joaquin Valley, California (USA), data from multiple sources were used to determine interrelations\\u000a among hydrogeologic factors, reduction-oxidation (redox) conditions, and temporal and spatial distributions of nitrate (NO3), a widely detected groundwater contaminant. Groundwater is predominantly modern, or mixtures of modern water, with detectable\\u000a NO3 and oxic redox conditions, but some zones have

Matthew K. Landon; Christopher T. Green; Kenneth Belitz; Michael J. Singleton; Bradley K. Esser

283

The role of hydrogeological base level in the formation of sub-horizontal caves horizons, example from the Dead Sea Basin, Israel  

Microsoft Academic Search

This paper deals with the hydrogeological relationship between base levels of saline lakes and the formation of sub-horizontal\\u000a caves. The mechanism presented here suggests that many horizontal cave levels in carbonate sequences are created adjacent\\u000a to the saline lakes shorelines because of the converging of the groundwater flow above the fresh–saline water interface. The\\u000a main factors that control enhanced carbonate

Uri Kafri; Yoseph Yechieli

2010-01-01

284

Consequences of marginal drainage from a raised bog and understanding the hydrogeological dynamics as a basis for restoration  

NASA Astrophysics Data System (ADS)

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

Regan, Shane; Johnston, Paul

2010-05-01

285

Death Valley regional ground-water flow system, Nevada and California -- hydrogeologic framework and transient ground-water flow model  

USGS Publications Warehouse

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

edited by Belcher, Wayne R.

2004-01-01

286

Death Valley regional groundwater flow system, Nevada and California-Hydrogeologic framework and transient groundwater flow model  

USGS Publications Warehouse

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

Edited by: Belcher, Wayne R.; Sweetkind, Donald S.

2010-01-01

287

Calendar year 1994 groundwater quality report for the Upper East Fork Poplar Creek Hydrogeologic Regime, Y-12 Plant, Oak Ridge, Tennessee  

SciTech Connect

This groundwater quality report (GWQR) contains an evaluation of the groundwater quality data obtained during the 1994 calendar year (CY) at several waste-management facilities and a petroleum fuel underground storage tank (UST) site at the US Department of Energy (DOE) Y-12 Plant located on the DOE Oak Ridge Reservation (ORR) southeast of Oak Ridge, Tennessee. These sites lie within the boundaries of the Upper East Fork Poplar Creek Hydrogeologic Regime (East Fork Regime), which is one of three hydrogeologic regimes defined for the purposes of groundwater quality monitoring at the Y-12 Plant. The Environmental Management Department of the Y-12 Plant Health, Safety, Environment, and Accountability (HSEA) Organization manages the groundwater monitoring activities in each regime under the auspices of the Y-12 Plant Groundwater Protection Program (GWPP). The purpose of the GWPP is to characterize the hydrogeology and to monitor groundwater quality at the Y-12 Plant and surrounding area to ensure protection of local groundwater resources in accordance with federal, state, and local regulations, DOE Orders, and Lockheed Martin Energy Systems, Inc. (Energy Systems) corporate policy.

NONE

1995-10-01

288

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

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.

edited by McKinney, Kevin C.

2005-01-01

289

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

USGS Publications Warehouse

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.

Wright, Peter R.

2010-01-01

290

Regional hydrogeology and hydrochemistry of deep formation waters in the Williston Basin (Canada-USA): implications for fluid migration in the basin  

NASA Astrophysics Data System (ADS)

The regional groundwater flow-system in the Williston Basin (Canada-USA) is one of the best examples of a mega-scale confined aquifer-system in the world. With its well-defined recharge and discharge areas separated by approximately 1000 km horizontal and 1 km vertical distance, the basin is an ideal natural laboratory to study regional groundwater flow and hydrochemistry. Springs and shallow water wells in the recharge and discharge areas, along with deeper oil and gas wells, allow for detailed mapping of formation-pressures. Further, these wells provide access for sampling and geochemical analyses of formation waters along flow paths. Basin-scale hydrogeological and hydrochemical mapping combined with newly obtained geochemical and isotopic data from more than 2000 wells across the basin provide new insights into the present and paleohydrogeology of the basin. Results indicate: 1) the hydrogeology and hydrochemistry of the basin must be mapped on hydrogeological (not political) boundaries; 2) many aquifers have similar water chemistries, yet unique isotopic fingerprints; 3) stable isotope distributions provide insight(s) into regional fluid flow patterns; 4) analysis of bromine concentrations and stable isotopic compositions provide evidence that at least some of the brine in the basin owes its origin to evaporated seawater and not just dissolved evaporites as previously thought; 5) regional patterns of stable isotopes and halogens can be used to trace different flow "events" in the basin's history; 6) calcium-rich brines in the center of the basin may be associated with relict calcium-rich seawaters; 7) hydrocarbon migration pathways have been variably impacted by evolving hydrodynamic conditions; and 8) there is strong evidence of past glacially-driven recharge in the current discharge area of the basin. These observations show that the hydrogeology and hydrochemistry of the basin is more complex than previously thought. Portions of the basin appear to respond rapidly to changes in boundary conditions including: the recharge areas; midline areas that have experienced extensive salt dissolution; and present discharge areas that appear to show evidence of glacially-driven recharge. Other portions of the basin appear to have had little to no fluid-flow despite being continuous and highly-permeable. Mixing, and not depth, appears to control water compositions. Insights gained from regional hydrogeology and hydrochemical provide an improved understanding the present and past mega-scale fluid migration in the Williston Basin.

Rostron, B. J.

2010-12-01

291

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)

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.

Benabderrahmane, H.; Cornaton, F. J.; Kerrou, J.

2009-12-01

292

Considering Variable Hydrogeology in an Assessment of Regional Shallow Ground-Water Quality in the Mid-Atlantic Coastal Plain, USA  

NASA Astrophysics Data System (ADS)

The variable surficial hydrogeology of the Mid-Atlantic Coastal Plain affects the nature and extent of natural and human influences on regional shallow ground-water quality. Water-quality data collected from 533 shallow wells (median depth of 11 meters) in unconfined aquifers of the Coastal Plain (New Jersey through North Carolina) were compiled from various sources for regional synthesis. These data were compared to a surficial hydrogeologic framework that was developed to provide a template for understanding the major physical processes affecting chemical transport and transformations in the shallow hydrologic system. Seven hydrogeologic subregions of the framework were defined to represent areas of similar geology (primarily siliciclastic sediments) along a continuum of sediment textures and physiography. Although the usefulness of data compiled from multiple sources for regional assessments is limited, broad patterns of similar water chemistry are apparent when the compiled data are analyzed within the context of the hydrogeologic framework. The quality of shallow unconfined ground water in the Mid-Atlantic Coastal Plain is related to aquifer redox properties and the distribution of soluble minerals, as well as land use. In agricultural areas, for example, nitrate concentrations (as nitrogen) rarely exceed 3 mg/L (milligrams per liter) where dissolved oxygen concentration is low (less than 1.4 mg/L), but commonly exceed 10 mg/L where dissolved oxygen concentration is higher (greater than 7.7 mg/L). Conversely, concentrations of phosphorus (which can be mobilized in ground water under reducing conditions) among all land uses decrease with increasing dissolved oxygen concentration (rho = -0.438, p < 0.0001). Regionally, specific conductance, pH, and concentrations of organic carbon, iron, and most nutrients and major ions are higher in the Coastal Lowlands subregion (a poorly drained area of abundant organic matter and little dissolved oxygen) than in a subregion of the Middle Coastal Plain with similar land use but coarser, more weathered sediments (mostly quartz) and better drainage. Nitrate and dissolved oxygen concentrations are lower in the Coastal Lowlands subregion. These differences likely are related to the greater availability of soluble aquifer materials in the Coastal Lowlands, as well as the variable redox and drainage conditions. Among other more hydrogeologically variable subregions, ground-water quality typically is indistinguishable and intermediate between these two subregions.

Ator, S. W.; Denver, J. M.; Hancock, T. C.

2001-05-01

293

Hydrogeology and water-quality conditions at the City of Olathe Landfill, east-central Kansas, 1990-93  

USGS Publications Warehouse

Water quality at the City of Olathe Landfill in east-central Kansas was examined in relation to hydrogeologic conditions to help determine the effects of the landfill on shallow ground water. This study focused on the Wyandotte and Plattsburg Limestones underlying the landfill. The Wyandotte Limestone underlies the entire landfill, whereas the overlying Plattsburg Limestone crops out within the landffll boundaries. Little Cedar Creek, an unnamed tributary, and a pond are located in the landfill. Water samples from seven monitoring wells and five surface-water sites in the vicinity of the City of Olathe Landfill were collected for analysis of inorganic and organic constituents. The inorganic constituents in the ground water that are most affected in the vicinity of the landfill are calcium, magnesium, sodium, bicarbonate, ammonia, barium, iron, and manganese. The dissolved- organic-carbon concentration at a seep flowing from the Plattsburg Limestone was 1,400 milligrams per liter, indicating that the landfill is affecting the water quality near the seep. Benzene was detected in all of the water samples, and the largest concentration was in a sample collected upgradient of the landfill. The benzene concentration exceeded the U.S. Environmental Protection Agency's Maximum Contaminant Level (0.005 milligram per liter) for drinking-water supplies. Six of the eight specific organic compounds detected were found in a water sample collected from the Plattsburg Limestone immediately downgradient of the landfill. No organic compoands, except benzene, were detected in samples collected from the Wyandotte Limestone downgradient of the landfill.

Rasmussen, P. P.; Shockley, J. C.; Hargadine, D. A.

1994-01-01

294

Well-construction, hydrogeologic, and ground-water-quality data in the vicinity of Belvidere, Boone County, Illinois  

USGS Publications Warehouse

The data base contains information for 725 water-supply and monitoring wells and lithologic borings. The sources of the data and methodology utilized to develop the data base are discussed. Well-construction and hydrogeologic data include well-identification label, latitude and longitude of the well locations, type of well, aquifer to which the well is open, total depth of the well, depth to water in the well, the screened or open interval, and owner information. Water-quality data are tabulated for concentrations of selected volatile organic compounds (VOC's) and semivolatile organic compounds, inorganic compounds, and total pesticide, and specific conductance. Data are provided on a floppy diskette accompanying the report. About 78 percent of the wells in the data base are water-supply wells, including eight municipal water-supply wells. About 40 percent of the wells are open to the glacial drift aquifer, and 53 percent are open to the Galena-Platteville aquifer. The remaining wells are open to multiple-bedrock aquifers. Of the 157 wells and borings with available water-quality data, 59 percent are open to the glacial drift aquifer, 24 percent are open to the Galena-Platteville aquifer, and 17 percent are open to multiple-bedrock aquifers. VOC's have been detected in six municipal and three domestic wells. Maximum contaminant levels of four VOC's have been exceeded periodically in four municipal wells.

Brown, Timothy A.; Mills, Patrick C.

1995-01-01

295

Selected hydrogeologic data from the Cedar Rapids Area, Benton and Linn counties, Iowa, October 1992 through March 1996  

USGS Publications Warehouse

The city of Cedar Rapids, Iowa, obtains its water supply from shallow wells screened in the alluvial aquifer along the Cedar River. A cooperative study between the city of Cedar Rapids, Iowa, and the U.S. Geological Survey was started in March 1992 to assess the water quality and water quantity of the ground-water resource. This report summarizes selected hydrogeologic data collected from October 1992 through March 1996. Information collected includes water quality (major ions, nutrients, and pesticides), ground-water levels, multiprobe-instrument (water levels, specific conductance, pH, water temperature, and dissolved oxygen monitored at 15-, 30-, or 60-minute intervals), well information (location, casing type, screen interval, and depth), and geophysical seismic- refraction and seismic-reflection data (estimated depth to bedrock and alluvial thickness along the Cedar River). Geologic, hydrologic, and water-quality data were collected from domestic, municipal, observation, and industrial wells and the Cedar River. Well-construction data for more than 300 wells in the Cedar Rapids area in Benton and Linn Counties, Iowa, were compiled primarily from records on file with the Iowa Department of Natural Resources, Geologic Survey Burea (Iowa City).

Schnoebelen, D. J.; Schulmeyer, P. M.

1996-01-01

296

Hydrogeological aspects and environmental concerns of the New Valley Project, Western Desert, Egypt, with special emphasis on the southern area  

SciTech Connect

The New Valley Project has been given much attention in the past 20 years especially from the hydrogeological point of view concerning groundwater utilization for the reclamation of a large area of the Western Desert. Lithological, petrophysical, and petrographical studies were conducted on four wells south of Beris Oasis. The Nubian sandstones in the area south of Beris Oasis contain hematitic stains and/or fine granular authigenic hematite, thin laminae of brown ferruginous quartzite is also recorded denoting oxidizing conditions in the basin of deposition. Thin streaks of carbonaceous shales are met with in different depths to the south of Beris area, may be taken to denote oscillations in the sea level and accordingly its depths, and are responsible for the change in the oxidation-reduction potential during the deposition of the corresponding beds. Petrographic examination of a thin section of the subsurface Nubia sandstones in the South of Beris Oasis showed that the lithified rocks fail into three types depending on the nature of cement being, silicious or ferruginous, and on the amount of primary matrix, which at present is reorganized into iron oxides, microquartz, and muscovite flakes, thus reaching the phyllomorphic stage of diagenesis. Rounding of the quartz grains shows that transportation had a minor effect on the grain morphology and favor a fluviatile transporting agent.

Assaad, F.A. (P.E. LaMoreaux and Associates, Tuscaloosa, AL (United States))

1988-12-01

297

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

NASA Astrophysics Data System (ADS)

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.

Chiocchini, Ugo; Castaldi, Fabio

2011-05-01

298

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

USGS Publications Warehouse

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.

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

2011-01-01

299

Flowpath structure in a limestone aquifer: multi-borehole logging investigations at the hydrogeological experimental site of Poitiers, France  

NASA Astrophysics Data System (ADS)

Since 2002, a new hydrogeological experimental site (HES) has been developed in Poitiers, France. The overall research objective related to this site is to improve the understanding of flow and solute transport in carbonate aquifers. The benchmarking of various types of numerical models against the HES field data is one of the main research projects supported by three national scientific programs. Within this framework, the purpose of this report is to synthesize existing knowledge about both aquifer geology and flowpath structure, based on core analysis and well logging. The combined use of core-hole data, borehole logs and outcrop data provide valuable information about lithostratigraphy and fracturing. The comparison of flow-meter data with borehole images indicates that flowpaths in the HES aquifer are strongly constrained within (1) subhorizontal karstic structures and (2) subvertical fractures. The presence of karstic levels appears to be conditioned by the stratigraphy and are unevenly developed in the HES. The vertical interconnectivity between the three karstic levels seems to result from fractures occurrence in this limestone formation. Following the observations, data and interpretations, a conceptual model of the Dogger aquifer is proposed.

Audouin, O.; Bodin, J.; Porel, G.; Bourbiaux, B.

2008-08-01

300

The distribution and hydrogeological controls of fluoride in the groundwater of central Ethiopian rift and adjacent highlands  

NASA Astrophysics Data System (ADS)

Occurrence of fluoride (F) in groundwater has drawn worldwide attention, since it has considerable impact on human health. In Ethiopia high concentrations of F in groundwaters used for community water supply have resulted in extensive dental and skeletal fluorosis. As a part of a broader study, the distribution of F in groundwater has been investigated, and compared with bedrock geology and pertinent hydrochemical variables. The result indicates extreme spatial variations. High F concentration is often associated with active and sub-active regional thermal fields and acidic volcanics within high temperature rift floor. Variations in F can also be related to changes in calcium concentration resulting from dissolution of calcium minerals and mixing with waters of different chemical composition originated from variable hydrogeological environment across the rift valley. The concentration of F dramatically declines from the rift towards the highlands with the exception of scattered points associated with thermal springs confined in local volcanic centers. There are also interactions of F-rich alkaline lakes and the surrounding groundwater. Meteoric waters recharging volcanic aquifers become enriched with respect to F along the groundwater flow path from highland recharge areas to rift discharge areas. Locally wells drilled along large rift faults acting as conduits of fresh highland waters show relatively lower F. These areas are likely to be possible sources of better quality waters within the rift. The result of this study has important implications on site selection for water well drilling.

Ayenew, Tenalem

2008-05-01

301

Hydrogeological characterization and assessment of groundwater quality in shallow aquifers in vicinity of Najafgarh drain of NCT Delhi  

NASA Astrophysics Data System (ADS)

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.

Shekhar, Shashank; Sarkar, Aditya

2013-02-01

302

Hydrogeological controls and indicators for oil deposits in rift grabens - An example from the Upper Rhine graben, France  

SciTech Connect

The Pechelbronn petroliferous region of northeast France is located on the west side of the Upper Rhine graben between the Vosges and Black Forest Mountains. Commercial oil occurs in Mesozoic and often Tertiary lenticular, faulted formations at various depths. In areas of oil fields and along fault zones, positive temperature anomalies at shallow and great depths (geothermal gradient: 10{degree}C/100 m), high salinities (TDS > 50,000 mg/L), and anomalously high Sr{sup {minus}}, Br{sup {minus}}, and I{sup {minus}} concentrations in shallow ground waters, flowing wells, and oil/gas seeps have been observed. These phenomena may be explained by topography-induced regionally ascending cross-formational groundwater flow. This interpretation is supported by the isotopic composition of the formation waters, suggesting a meteoric origin, relatively young {sup 14}c ages ({approx} 30,000 years), and calculated flow velocities of 0.30 m/year as well as numerical modeling. Ground-water recharges in the topographic highs, converges toward the Graben basin, and discharges under artesian conditions by vertically ascending flow, preferentially along conductive faults. Vertical migration of hydrocarons is also suggested by high methane concentrations in soils observed across faults with isotope ratios indicative of thermally mature hydrocarbon gases originating at depth. Consequently, a dynamic-genetic relationship appears to exist between basinal ground-water flow, hydrocarbon accumulations, and observed natural phenomena. This relationship may be used for hydrogeological-based exploration for hydrocarbons, complementing conventional methods.

Otto, C.J.; Toth, J. (Univ. of Alberta, Edmonton (Canada))

1988-08-01

303

Model evaluation of the hydrogeology of the Morris Bridge well field : and vicinity in West-Central Florida  

USGS Publications Warehouse

The Morris Bridge well field in west-central Florida, which is being developed may have a maximum well-field withdrawal of 40 million gallons per day. The water will be pumped from the Floridan aquifer--a sequence of carbonate rocks about 1,100 feet thick underlying surficial sand and clay deposits. A highly fractured and transmissive zone about 500 feet below National Geodetic Vertical Datum of 1929 will supply a large proportion of the water. Two-dimensional and three-dimensional digital flow models were used to evaluate the hydrogeology of the area. The model-derived leakance distribution (a property of the confining bed) for a 285-square-mile area ranged from 0.00002 to 0.008 per day. Model-derived transmissivity values for the Floridan aquifer ranged from 37,000 to 600,000 feet squared per day. Model-derived specific yield values for the surficial aquifer ranged from 0.05 to 0.30. The three-dimensional model was used to predict drawdowns in both the Floridan and surficial aquifers in response to a 40 million gallon per day stress. Mass-balance data from a 30-day simulation with no recharge from rainfall show percentage of withdrawn water that is derived from: (1) aquifer storage, (2) the Hillsborough River, and (3) reduction of evapotranspiration losses. (USGS)

Ryder, Paul D.; Johnson, Dale M.; Gerhart, James M.

1980-01-01

304

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

NASA Astrophysics Data System (ADS)

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.

Golts, S.; Rosenthal, E.

1992-01-01

305

Stochastic hydrogeological modelling of fractured rocks: a generic case study in the Mórágy Granite Formation (South Hungary)  

NASA Astrophysics Data System (ADS)

In connection with the Hungarian radioactive waste disposal program a detailed study of the mass properties of the potential host rock (granite) has been carried out. Using the results of this study the various parameters (orientation, length, intensity, transmissivity, etc.) describing a fracture set were estimated on the basis of statistical considerations. These estimates served as basic input parameters for stochastic hydrogeological modelling of discrete fracture networks (DFN), which is a strongly developing area of hydrology, providing geologically realistic geometry for site investigations. The synthetic fracture systems generated were tested against some (but not all) field observations. The models built up on the basis of the statistical descriptions showed the same equivalent hydraulic conductivity for the modelled region as the field measurements. In addition, the models reproduce the observed hydraulic head-scattering along vertical boreholes. On the basis of the stochastic simulations of the fracture system some input parameters for the performance assessment of the planned repository were investigated. Calculation of flows into a planned disposal tunnel indicated that if the hydraulic conductivity of the material in the tunnel is the only variable parameter then there are two thresholds: under 1×10-9 m/s and above 1×10-5 m/s further change of the hydraulic conductivity does not dramatically affect the inflow.

Benedek, Kálmán; Dankó, Gyula

2009-08-01

306

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

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.

Anderman, Evan R.; Kipp, K. L.; Hill, Mary C.; Valstar, Johan; Neupauer, R. M.

2002-01-01

307

Hydrogeology, ground-water quality, and potential for water-supply contamination near the Shelby County landfill in Memphis, Tennessee  

USGS Publications Warehouse

An investigation was conducted from 1989 to 1991 to collect and interpret hydrogeologic and ground-water-quality data specific to the Shelby County landfill in east Memphis, Tennessee. Eighteen wells were installed in the alluvial and Memphis aquifers at the landfill. Hydrogeologic data collected showed that the confining unit separating the alluvial aquifer from the Memphis aquifer was thin or absent just north of the landfill and elsewhere consists predominantly of fine sand and silt with lenses of clay. A water-table map of the landfill vicinity confirms the existence of a depression in the water table north and northeast of the landfill and indicates that ground water flows northeast from the Wolf River passing beneath the landfill toward the depression in the water table. A map of the potentiometric surface of the Memphis aquifer shows that water levels were anomalously high just north of the landfill, indicating downward leakage of water from the alluvial aquifer to the Memphis aquifer. An analysis of water-quality data for major and trace inorganic constituents and nutrients confirms that leachate from the landfill has migrated northeastward in the alluvial aquifer toward the depression in the water table and that contaminants in the alluvial aquifer have migrated downward into the Memphis aquifer. The leachate plume can be characterized by concentrations of certain major and trace inorganic constituents that are 2 to 20 times higher than samples from upgradient and background alluvial aquifer wells. The major and trace constituents that best characterize the leachate plume are total organic carbon, chloride, dissolved solids, iron, ammonia nitrogen, calcium, sodium, iodide, barium, strontium, boron, and cadmium. Several of these constituents (specifically dissolved solids, calcium, sodium, and possibly ammonia nitrogen, chloride, barium, and strontium) were detected in elevated concentrations in samples from certain Memphis aquifer wells. Elevated concentrations were detected in samples from the Memphis aquifer beneath the leachate plume where the confining unit is thin or absent. The distribution of halogenated alkanes (specifically dichlorodifluoromethane and trichlorofluoromethane) and halogenated alkenes (specifically 1,2-trans-dichloroethene and vinyl chloride) in samples from wells screened in both the alluvial and Memphis aquifers is similar to the distribution of major and trace inorganic constituents that characterize the leachate plume. The ground-water supply most susceptible to contamination from the Shelby County landfill is the Sheahan well field of the Memphis Light, Gas and Water Division. This well field is about 5 miles downgradient from the landfill in the direction of ground-water flow. Based on an estimated velocity of 0.5 to 1.5 feet per day, ground water would require about 50 to 150 years to travel from the Shelby County landfill to the Sheahan wellfield. Given the time and distance of transport, any contaminants in the ground water would not likely persistto reach this well field because of the effects of various physical, chemical, and biological processes, including dilution and adsorption.

Parks, W. S.; Mirecki, J. E.

1992-01-01

308

Hydrogeologic framework and estimates of groundwater storage for the Hualapai Valley, Detrital Valley, and Sacramento Valley basins, Mohave County, Arizona  

USGS Publications Warehouse

We have investigated the hydrogeology of the Hualapai Valley, Detrital Valley, and Sacramento Valley basins of Mohave County in northwestern Arizona to develop a better understanding of groundwater storage within the basin fill aquifers. In our investigation we used geologic maps, well-log data, and geophysical surveys to delineate the sedimentary textures and lithology of the basin fill. We used gravity data to construct a basin geometry model that defines smaller subbasins within the larger basins, and airborne transient-electromagnetic modeled results along with well-log lithology data to infer the subsurface distribution of basin fill within the subbasins. Hydrogeologic units (HGUs) are delineated within the subbasins on the basis of the inferred lithology of saturated basin fill. We used the extent and size of HGUs to estimate groundwater storage to depths of 400 meters (m) below land surface (bls). The basin geometry model for the Hualapai Valley basin consists of three subbasins: the Kingman, Hualapai, and southern Gregg subbasins. In the Kingman subbasin, which is estimated to be 1,200 m deep, saturated basin fill consists of a mixture of fine- to coarse-grained sedimentary deposits. The Hualapai subbasin, which is the largest of the subbasins, contains a thick halite body from about 400 m to about 4,300 m bls. Saturated basin fill overlying the salt body consists predominately of fine-grained older playa deposits. In the southern Gregg subbasin, which is estimated to be 1,400 m deep, saturated basin fill is interpreted to consist primarily of fine- to coarse-grained sedimentary deposits. Groundwater storage to 400 m bls in the Hualapai Valley basin is estimated to be 14.1 cubic kilometers (km3). The basin geometry model for the Detrital Valley basin consists of three subbasins: northern Detrital, central Detrital, and southern Detrital subbasins. The northern and central Detrital subbasins are characterized by a predominance of playa evaporite and fine-grained clastic deposits; evaporite deposits in the northern Detrital subbasin include halite. The northern Detrital subbasin is estimated to be 600 m deep and the middle Detrital subbasin is estimated to be 700 m deep. The southern Detrital subbasin, which is estimated to be 1,500 m deep, is characterized by a mixture of fine- to coarse-grained basin fill deposits. Groundwater storage to 400 m bls in the Detrital Valley basin is estimated to be 9.8 km3. The basin geometry model for the Sacramento Valley basin consists of three subbasins: the Chloride, Golden Valley, and Dutch Flat subbasins. The Chloride subbasin, which is estimated to be 900 m deep, is characterized by fine- to coarse-grained basin fill deposits. In the Golden Valley subbasin, which is elongated north-south, and is estimated to be 1,300 m deep, basin fill includes fine-grained sedimentary deposits overlain by coarse-grained sedimentary deposits in much of the subbasin. The Dutch Flat subbasin is estimated to be 2,600 m deep, and well-log lithologic data suggest that the basin fill consists of interlayers of gravel, sand, and clay. Groundwater storage to 400 m bls in the Sacramento Valley basin is estimated to be 35.1 km3.

Truini, Margot; Beard, L. Sue; Kennedy, Jeffrey; Anning, Dave W.

2013-01-01

309

New packer experiments and borehole logs in upper oceanic crust: Evidence for ridge-parallel consistency in crustal hydrogeological properties  

NASA Astrophysics Data System (ADS)

We report new drillstring packer permeability tests conducted during Integrated Ocean Drilling Program (IODP) Expedition 327 in upper oceanic basement in Hole U1362A on the eastern flank of the Juan de Fuca Ridge. Hole U1362A lies within a closely spaced array (40-2460 m separation) of six holes in well-sedimented 3.5-3.6 m.y. old crust that were drilled, tested, and instrumented with borehole observatories during Ocean Drilling Program Leg 168 and IODP Expeditions 301 and 327. The permeability tests in Hole U1362A complement similar experiments previously conducted in nearby Holes 1026B, 1027C, and U1301B. The new results suggest consistency of upper crustal permeability between Holes U1362A and U1301B, which penetrate 290 and 320 m of basement and are separated by ˜825 m. We obtain similar bulk permeability values of 1-3 × 10-12 m2 for the sections deeper than ˜150 m into basement in both holes. These values are significantly higher than results of packer experiments in the shallowest few tens of meters of basement in nearby Holes 1026B and 1027C, suggesting that the highest basement permeabilities in this area are not found in the shallowest basement layers. Downhole logs of density and penetration rate during drilling and coring in Holes U1362A and U1301B show similar trends within the upper crust, reinforcing the inference that there may be considerable lateral continuity in hydrogeologic properties. This continuity may be associated with the fundamental lithostratigraphy of the crust and/or influenced by ridge-parallel faulting and fracturing associated with the formation of abyssal hill topography.

Becker, Keir; Fisher, Andrew T.; Tsuji, Takeshi

2013-08-01

310

Water geochemistry and hydrogeology of the shallow aquifer at Roosevelt Hot Springs, southern Utah: A hot dry rock prospect  

SciTech Connect

On the western edge of the geothermal field, three deep holes have been drilled that are very hot but mostly dry. Two of them (Phillips 9-1 and Acord 1-26 wells) have been studied by Los Alamos National Laboratory for the Hot Dry Rock (HDR) resources evaluation program. A review of data and recommendations have been formulated to evaluate the HDR geothermal potential at Roosevelt. The present report is directed toward the study of the shallow aquifer of the Milford Valley to determine if the local groundwater would be suitable for use as make-up water in an HDR system. This investigation is the result of a cooperative agreement between Los Alamos and Phillips Petroleum Co., formerly the main operator of the Roosevelt Hot Springs Unit. The presence of these hot dry wells and the similar setting of the Roosevelt area to the prototype HDR site at Fenton Hill, New Mexico, make Roosevelt a very good candidate site for creation of another HDR geothermal system. This investigation has two main objectives: to assess the water geochemistry of the valley aquifer, to determine possible problems in future make-up water use, such as scaling or corrosion in the wells and surface piping, and to assess the hydrogeology of the shallow groundwaters above the HDR zone, to characterize the physical properties of the aquifer. These two objectives are linked by the fact that the valley aquifer is naturally contaminated by geothermal fluids leaking out of the hydrothermal reservoir. In an arid region where good-quality fresh water is needed for public water supply and irrigation, nonpotable waters would be ideal for an industrial use such as injection into an HDR energy extraction system. 50 refs., 10 figs., 10 tabs.

Vuataz, F.D.; Goff, F.

1987-12-01

311

Hydrogeology and simulation of ground-water flow at Arnold Air Force Base, Coffee and Franklin counties, Tennessee  

USGS Publications Warehouse

The U.S. Air Force at Arnold Air Force Base (AAFB), in Coffee and Franklin Counties, Tennessee, is investigating ground-water contamination in selected areas of the base. This report documents the results of a comprehensive investigation of the regional hydrogeology of the AAFB area. Three aquifers within the Highland Rim aquifer system, the shallow aquifer, the Manchester aquifer, and the Fort Payne aquifer, have been identified in the study area. Of these, the Manchester aquifer is the primary source of water for domestic use. Drilling and water- quality data indicate that the Chattanooga Shale is an effective confining unit, isolating the Highland Rim aquifer system from the deeper, upper Central Basin aquifer system. A regional ground-water divide, approximately coinciding with the Duck River-Elk River drainage divide, underlies AAFB and runs from southwest to northeast. The general direction of most ground-water flow is to the north- west or to the northwest or to the southeast from the divide towards tributary streams that drain the area. Recharge estimates range from 4 to 11 inches per year. Digital computer modeling was used to simulate and provide a better understanding of the ground-water flow system. The model indicates that most of the ground-water flow occurs in the shallow and Manchester aquifers. The model was most sensitive to increases in hydraulic conductivity and changes in recharge rates. Particle-tracking analysis from selected sites of ground-water contamination indicates a potential for contami- nants to be transported beyond the boundary of AAFB.

Haugh, C. J.; Mahoney, E. N.

1994-01-01

312

The Effects of Gravity-Induced Stresses on Hydrogeologic Properties Near Ridges: Examples From two Rift Basins  

NASA Astrophysics Data System (ADS)

Twenty Mesozoic rift basins have been identified along the northeast coast of North America. At two of these, the Minas Basin in Nova Scotia and the Newark Basin in New York, steep topographic ridges formed initially by extensional tectonic processes have been evaluated for groundwater potential by obtaining geophysical logs in nearby water wells. The two locations have common lithologic and topographic characteristics, whereby a basalt cap overlying sedimentary rocks is exposed along a ridge flank. Despite these similarities, the basalts in Nova Scotia serve as a local water supply whereas the wells in New York are non-producing. Analyses of acoustic televiewer logs and measurements from flowmeter/pumping tests locate and distinguish the permeable fractures from the general fracture population. In addition, a complementary finite-element stress model is used to simulate ridge geometry from topographic maps and incorporates rock elastic properties as determined from processing full-waveform sonic logs. Results derived from field data and modeling indicate that gravity-induced stresses near ridges result from a lack of buttressing along the free faces and are amplified by spreading effects due to a contrast in Poisson's ratio between the basalts and the sedimentary rocks. These conditions act to enhance the permeability of fractures striking subparallel to the ridge axis in Nova Scotia. Conversely, the predominant fracture population in New York strikes perpendicular to the ridge axis and to the maximum horizontal principal stress. Consequently, there are few fractures preferentially aligned with the stress field and no hydraulically conductive features are recognized in these rocks. The hydrogeologic properties of the basalts near the ridge flanks at these two sites are markedly different because of the orientation of pre-existing fractures and their response to imposed stresses as derived from topography and lithostratigraphy.

Savage, W. Z.; Morin, R. H.; Matter, J. M.; Rivard, C.; Goldberg, D. S.

2007-12-01

313

Hydrogeology and simulation of groundwater flow at the Green Valley reclaimed coal refuse site near Terre Haute, Indiana  

USGS Publications Warehouse

The Green Valley reclaimed coal refuse site, near Terre Haute, Ind., was mined for coal from 1948 to 1963. Subsurface coal was cleaned and sorted at land surface, and waste material was deposited over the native glacial till. Approximately 2.7 million cubic yards of waste was deposited over 159 acres (92.3 hectares) in tailings ponds and gob piles. During 1993, the Indiana Department of Natural Resources, Division of Reclamation, improved the site by grading gob piles, filling tailings ponds, and covering the refuse with a layer of glacial drift. During 2008, the Division of Reclamation and U.S. Geological Survey initiated a cooperative investigation to characterize the hydrogeology of the site and construct a calibrated groundwater flow model that could be used to simulate the results of future remedial actions. In support of the modeling, a data-collection network was installed at the Green Valley site to measure weather components, geophysical properties, groundwater levels, and stream and seep flow. Results of the investigation indicate that (1) there is negligible overland flow from the site, (2) the prevailing groundwater-flow direction is from northeast to southwest, with a much smaller drainage to the northeast, (3) there is not a direct hydraulic connection between the refuse and West Little Sugar Creek, (4) about 24 percent of the groundwater recharge emerges through seeps, and water from the seeps evaporates or eventually flows to West Little Sugar Creek and the Green Valley Mine Pond, and (5) about 72 percent of groundwater recharge moves vertically downward from the coal refuse into the till and follows long, slow flow paths to eventual dischage points.

Bayless, E. Randall; Arihood, Leslie D.; Fowler, Kathleen K.

2011-01-01

314

The hydrogeology of the Costa Rica Rift as constrained by results of ocean drilling program downhole experiments  

SciTech Connect

Pore fluids are passively convecting through young oceanic sediments and crust around Deep Sea Drilling Project (DSDP) site 504 on the southern flank of the Costa Rica Rift, as inferred from a variety of geological, geochemical, and geothermal observations. The presence of a fluid circulation system is supported by new data collected on Ocean Drilling Program (ODP) Leg 111 and a predrilling survey cruise over the heavily sedimented, 5.9 Ma site; during the latter, elongated heat flow anomalies were mapped subparallel to structural strike, with individual measurements of twice the regional mean value, and large lateral and vertical geochemical gradients were detected in pore waters squeezed from sediment cores. Also, there is a strong correlation between heat flow, bathymetry, sediment thickness, and inferred fluid velocities up through the sediments. On an earlier DSDP leg, an 8-bar underpressure was measured in the upper 200 m of basement beneath thick sediment cover. The widely varied geothermal and hydrogeological observations near site 504 are readily explained by a model that combines (1) basement relief, (2) irregular sediment drape, (3) largely conductive heat transfer through the sediments overlying the crust, and (4) thermal and geochemical homogenization of pore fluids at the sediment/basement interface, which results from (5) topographically induced, passive hydrothermal circulation with large aspect ratio, convection cells. This convection involves mainly the permeable, upper 200-300 m of crust; the deeper crust is not involved. This convection is induced through a combination of buoyancy fluxes, owing to heating from below, and topographic variations on the seafloor and at the basement-sediment interface.

Fisher, A.T. (Texas A and M Univ., College Station (USA)); Becker, K. (Univ. of Miami, FL (USA)); Narasimhan, T. (Lawrence Berkeley Lab., CA (USA))

1990-06-01

315

Seamount subduction changes hydrogeology to form chemosynthetic community-Finding of a huge community at the Cadet seamount, Kuril Trench-  

NASA Astrophysics Data System (ADS)

Huge chemosynthetic animal communities with carbonate chimneys and bacterial mats were found on the southern slope of the Cadet Seamount, a subducted seamount which was found in 1984 by the SeaBeam mapping at the southern end of the Kuril Trench forearc. We had three dives at depth range from 5340m to 4050m by submersible Shinkai 6500 in June 2002. Multi-channel Seismic profile line HK103 across the Erimo and Cadet seamounts indicate two strong and two weak landward dipping steep reflectors along the southern slope of the Cadet seamount. Two strong reflectors may correspond to sandy layer or highly deformed mud layers with large shear zone. However another line 101 across the normal Kuril Trench shows monotonous seaward dipping reflectors just like Japan Trench forearc. Chemosynthetic communities exist at depths from 5275m to 4490m with barren interval from 5200m to 4983m. Dense distribution of clam communities is existed at the depths about 5275m and 4675m. Sediments we observed along the dive tracks were highly deformed mudstone partly coarse sandstone with intercalated ash layers. They show the perfect EW trending stratification with about 20 degree landward dipping. Distribution of clams and stratification of sandstones and mudstones are well correlated to the seismic profile record across the Cadet seamount. We propose here the following model for the distribution of animal community. About 300,000 years ago Cadet seamount reached the Kuril Trench then started to subduct. Permeable layers in the front of the seamount pushed up gradually to form steep layers with deformation. The origin of fluid to sustain the community is estimated to be the interstitial water in the permeable layers. So the seamount subduction may change the hydrogeology of the tow area to offer the best place for chemosynthetic animal community.

Fujioka, K.; Sato, T.; Miwa, T.; Tsuru, T.; Kido, Y.; Nakanishi, A.; Kato, C.

2002-12-01

316

Ring of Cenotes (sinkholes), northwest Yucatan, Mexico: Its hydrogeologic characteristics and possible association with the Chicxulub impact crater  

NASA Astrophysics Data System (ADS)

A 180-km-diameter semicircular band of abundant karst sinkholes (Ring of Cenotes) in northwest Yucatan, Mexico, coincides approximately with a concentric ring of the buried Chicxulub structure, a circular feature manifested in Cretaceous and older rocks, that has been identified as the product of the impact of a bolide. The ring, expressed in Tertiary rocks, marks a zone of high permeability as shown by (1) the sinkholes themselves, (2) breaks in the coastal dune system and high density of springs where the ring intersects the coast, and (3) water-level transects characterized by a decline in water level toward the ring. Any direct relation that exists between the Ring of Cenotes and the Chicxulub structure bears on regional hydrogeology. If the layer or zone responsible for the ring is deeply buried, it may act as a barrier to the movement of ground water across the main flow direction. Shallower zones of horizontal permeability could result in less complete diversion of ground water. Through its influence on Yucatan aquifer characteristics, the ring may provide a link between modern environmental problems and astrogeology. Possible origins for the Ring of Cenotes are (1) faulting, perhaps reactivated by post-Eocene mid-Miocene basin loading, (2) permeability in a buried reef complex developed in the shallow Paleocene sea around the crater rim, or (3) breccia collapse occasioned by consolidation or by solution of evaporite components. If the ring developed on ancient faults, it may outline hydrothermal systems and mineral deposits produced during Paleocene cooling of the Chicxulub melt sheet.

Perry, Eugene; Marin, Luis; McClain, Jana; Velazquez, Guadalupe

1995-01-01

317

Hydrogeologic framework of the shallow ground-water system in the Cox Hall Creek basin, Cape May County, New Jersey  

USGS Publications Warehouse

Cape May County is investigating the feasibility of restoring the lowermost reach of Cox Hall Creek to its former state as a tidal saltwater wetland; however, the potential for contamination of the shallow ground-water system, which provides water to hundreds of nearby privately owned domestic wells, with saltwater from the restored wetland is of particular concern. To evaluate the potential effectiveness and risks of restoring the saltwater wetlands, the County needs information about the hydrogeologic framework in the area, and about the potential vulnerability of the domestic wells to contamination. The shallow ground-water system in the Cox Hall Creek area consists of unconsolidated Holocene and Pleistocene deposits. The Holly Beach water-bearing zone, the unconfined (water-table) aquifer, is about 35 feet thick and contains a 2- to 4-foot-thick clay lens about 10 feet below land surface; a lower, more discontinuous clay lens about 30 to 35 feet below land surface ranges up to 5 feet in thickness. A 75-foot-thick confining unit separates the Holly Beach water-bearing zone from the underlying estuarine sand aquifer. The clay lenses in the Holly Beach water-bearing zone likely retard the movement of contaminants from septic tanks, lawns, and other surficial sources, protecting wells that tap the lower, sandy part of the aquifer. The clay lenses also may protect these wells from salty surface water if withdrawals from the Holly Beach water-bearing zone are not increased substantially. Deeper wells that tap the estuarine sand aquifer are more effectively protected from saltwater from surface sources because of the presence of the overlying confining unit.

Lacombe, Pierre J.; Zapecza, Otto S.

2006-01-01

318

Hydrogeological approach to investigation in karst for possible modification of groundwater regime and increase of recoverable reserves  

NASA Astrophysics Data System (ADS)

An artificial contribution to groundwater reserves in the areas of interest for water supply is a principal methodological target in modern hydrogeology. Investigations directed to this goal are of increasing significance all over the world to meet the growing demand for good water, which groundwater generally can be. Progress has been made in the sphere of practical development in permeable rocks of intergranular porosity, which cannot be said of discontinuous karst media, although it seems to offer greater opportunities. The ingrained notion and fear, even among specialists, of the inherent risk and uncertainty were invariably present wherever a resource was discovered in karst of a geosynclinal area; consequently progress has been limited. The reasons, however, for such a cautious approach are diminishing, because much knowledge has been gained about these aquiferous rocks, especially through investigations in the regions of surface storage reservoirs. Better knowledge of karst features and the results achieved in construction and consolidation of surface reservoirs have indicated that large amounts of groundwater can be recovered. The conventional water investigation and recovery methods have made available only small safe yields equal to the lowest natural discharge on the order of 100 I/sec). A reasonable use of a karst water resource and its better management cannot be considered without artificial control of the groundwater regime, i.e., without adjusting the regime to human demands. Groundwater flow balance in karst is becoming one of the principal problems, and future activities should be directed to the search for a bolder solution. A multidisciplinary team of geologists, geomorphologists, hydrogeologists, hydrologists, hydraulic engineers, etc., is required. In this paper a variety of solutions for water resource utilization in naked geosynclinal karst is suggested and far greater activity in this field is encouraged.

Komatina, Miomir

1990-09-01

319

A multidisciplinary geological and geophysical approach to define structural and hydrogeological implications of the Molinaccio spring (Spello, Italy)  

NASA Astrophysics Data System (ADS)

In this paper, a multidisciplinary geological and geophysical approach has been applied in the complex area of Molinaccio spring (Spello, Umbria, Central Italy) to: 1) understand the large-scale geologic and tectonic structure of the area; 2) define the hydrogeological behavior of the various formations in relationship with the identified structural elements; 3) highlight at small-scale the tectonic structures and their relationships with the water caption tunnel, which is the draining structure of a still working, ancient Roman aqueduct giving water to the village of Spello and to the surrounding plain.Our approach includes different techniques like Ground Penetrating Radar (GPR) and Electrical Resistivity Tomography (ERT), direct geological investigations, archaeological studies, GIS data collection and integration. The GPR data revealed, in the area of the water-caption tunnel, two main tectonic structures, both also confirmed by ERT data: the presence of a zone (maximum 2 m wide), interpreted as a normal fault area and an overthrust that puts in contact the permeable Scaglia Rossa limestone (Early Turonian-Middle Eocene), and the Scaglia Variegata-Cinerea marly limestones (Middle Eocene-Upper Oligocene) on the footwall, characterized by lower hydraulic permeability. Using some rough information available on the sub-surface path of the tunnel, that shows a sharp bend after a long straight course, together with the geophysical images, was possible to describe how Romans built the tunnel: they probably followed the wet outcropping rock during the excavation, and changed abruptly the dig direction when they intercepted the normal fault area, aligning then the excavation along its strike. This latter result is important also because recently a multidisciplinary project has been developed to restore and exploit the entire water supply structure, which is not only a well-preserved example of Roman remains with high archaeological value, but also a vital infrastructure for a zone with great tourist potential.

Ercoli, Maurizio; Pauselli, Cristina; Forte, Emanuele; Di Matteo, Lucio; Mazzocca, Massimiliano; Frigeri, Alessandro; Federico, Costanzo

2012-02-01

320

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

NASA Astrophysics Data System (ADS)

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 structure, including the frontal thrust and the decollement, with seismic reflection images was also determined.Bedding dips, faults and shear bands analyzed in the cores confirm the pattern of deformation to be mainly due to NW-SE shortening, as expected from the plate tectonic convergence vector. Below the decollement, no significant deformation features were observed, indicating that the decollement is a sharp discontinuity in stress transmission.Physical properties data show major discontinuities at the decollement, notably an increase in porosity below the later. This may indicate excess pore pressure in the subducted section and decollement zone. A less marked increase in porosity below the frontal thrust may reflect the youthfulness of this feature. Attempts to make downhole measurements were severely hampered by unstable hole conditions, but useful constraints have been placed on the thermal regime, and some calibration of laboratory physical properties toin-situ conditions has been provided, andin-situ stress and pore pressure were measured in the uppermost sediments.Evidence of channelized fluid flows is inconclusive. No sharp geochemical signatures or unequivocal geochemical anomalies indicative of channelized fluid flow were found. Thermal measurements are not significantly different from those predicted by a purely conductive heat flow model. A signature of low chloride pore water near the decollement may partly be related to smectite diagenesis but may also be due to episodic fluid flow events. We conclude that dewatering probably occurred dominantly through diffuse flow throughout the accreted sediments at this site.

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

1992-04-01

321

Hydrogeologic and Hydraulic Characterization of the Surficial Aquifer System, and Origin of High Salinity Groundwater, Palm Beach County, Florida  

USGS Publications Warehouse

Previous studies of the hydrogeology of the surficial aquifer system in Palm Beach County, Florida, have focused mostly on the eastern one-half to one-third of the county in the more densely populated coastal areas. These studies have not placed the hydrogeology in a framework in which stratigraphic units in this complex aquifer system are defined and correlated between wells. Interest in the surficial aquifer system has increased because of population growth, westward expansion of urbanized areas, and increased utilization of surface-water resources in the central and western areas of the county. In 2004, the U.S. Geological Survey, in cooperation with the South Florida Water Management District, initiated an investigation to delineate the hydrogeologic framework of the surficial aquifer system in Palm Beach County, based on a lithostratigraphic framework, and to evaluate hydraulic properties and characteristics of units and permeable zones within this framework. A lithostratigraphic framework was delineated by correlating markers between all wells with data available based primarily on borehole natural gamma-ray geophysical log signatures and secondarily, lithologic characteristics. These correlation markers approximately correspond to important lithostratigraphic unit boundaries. Using the markers as guides to their boundaries, the surficial aquifer system was divided into three main permeable zones or subaquifers, which are designated, from shallowest to deepest, zones 1, 2, and 3. Zone 1 is above the Tamiami Formation in the Anastasia and Fort Thompson Formations. Zone 2 primarily is in the upper part or Pinecrest Sand Member of the Tamiami Formation, and zone 3 is in the Ochopee Limestone Member of the Tamiami Formation or its correlative equivalent. Differences in the lithologic character exist between these three zones, and these differences commonly include differences in the nature of the pore space. Zone 1 attains its greatest thickness (50 feet or more) and highest transmissivity in coastal areas. Zone 2, the most transmissive and extensive zone, is thickest (80 feet or more) and most transmissive in the inland eastern areas near Florida's Turnpike. In this area, zone 1 is absent, and the semiconfining unit above zone 2 extends to the land surface with a thickness commonly ranging from 50 to 100 feet. The thickness of zone 2 decreases to zero in most wells near the coast. Zone 3 attains its greatest thickness (100 feet or more) in the southwestern and south-central areas; zone 3 is equivalent to the gray limestone aquifer. The distribution of transmissivity was mapped by zone; however, zones 2 and 3 were commonly combined in aquifer tests. Maximum transmissivities for zone 1, zones 2 and 3, and zone 3 were 90,000, 180,000, and 70,000 ft2/d (feet-squared per day), respectively. The northern extent of the area with transmissivity greater than 50,000 ft2/d for zones 2 and 3 in the inland northeastern area along Florida's Turnpike has not been defined based on available data and could extend 5 to 10 miles farther north than mapped. Based on the thickness of zone 2 and a limited number of aquifer tests, a large area of zone 2 with transmissivity greater than 10,000 ft2/d, and possibly as much as 30,000 ft2/d, extends to the west across Water Conservation Area 1 from the inland southeastern area into the south-central area and some of the southwestern area. In contrast to the Biscayne aquifer present to the south of Palm Beach County, zones 2 and 3 are interpreted to be present principally in the Tamiami Formation and are commonly overlain by a thick semiconfining unit of moderate permeability. These zones have been referred to as the 'Turnpike' aquifer in the inland eastern areas of Palm Beach County, and the extent of greatest thickness and transmissivity follows, or is adjacent to, Florida's Turnpike. Where it is thick and transmissive, zone 1 may be considered equivalent to the Biscayne aquifer. Areas

Reese, Ronald S.; Wacker, Michael A.

2009-01-01

322

Review of the R&D project of the advanced geophysical prospecting techniques for HLW repository siting from hydrogeological view point  

NASA Astrophysics Data System (ADS)

Nuclear Waste Management Organization of Japan (NUMO) implements geological disposal of high-level radioactive waste and long half-lives TRU waste. Considering the major scenario of safety assessment to be exposed radiation of geological disposal, the radio nuclides move closer to the biosphere by groundwater fluxion running through the repository toward the ground surface. Fault plane often becomes hydrogeological boundary such as groundwater sealing and/or conductive surface. Fault also often indicates relatively higher electric conductivity than intact rock under the influence of fully saturated fault gouge and breccia. One of the state-of-the-art geophysical techniques is 3D magnetotelluric method (MT). We have reviewed the 3D method to evaluate their applicability for characterizing hydrogeological structure of the fault in the different type of geology. The first case at Precambrian tonalite site, data indicated strike-slip structure as a low resistivity distribution. It also precisely indicated branching off in two parts in deeper area. It was easily visible to identify fault structure because of a large resistivity contrast between intact rock and fractured parts. The second case at the San Andreas Fault tracking site, data indicated fault plain as two different resistivity parts were contacted. It was understandable to identify existing fault from two different resistivity groups. The third case at Neogene soft sedimentary rock site, did not indicate good resistivity contrast to identify the fault structure. We conclude that the electromagnetic method is better to identify fault existence in good contrast geology between fractured and intact parts such as granite or two different rock types. It may be said, as a rule, these different resistivity distributions indicate hydraulic property, however there are still issues to evaluate hydrogeological feature such as a moisture content and permeability in the fault by geophysical methods.

Yoshimura, K.; Goto, J.

2011-12-01

323

Calendar year 1995 groundwater quality report for the Beak Creek Hydrogeologic Regime, Y-12 Plant, Oak Ridge, Tennessee. Part 2: 1995 groundwater quality data interpretations  

SciTech Connect

This annual groundwater quality report (GWQR) contains an evaluation of the groundwater and surface water monitoring data obtained during the 1995 calendar year (CY) for several hazardous and nonhazardous waste management facilities associated with the US DOE Y-12 Plant. The sites addressed by this document are located in Bear Creek Valley (BCV) west of the Y-12 Plant complex within the Bear Creek Hydrogeologic Regime. The Bear Creek Regime is one of three hydrogeologic regimes defined for the purposes of groundwater and surface water quality monitoring at the Y-12 Plant. The purpose of the GWPP is to characterize the hydrogeology and to monitor groundwater quality at the Y-12 Plant and surrounding area to provide for protection of groundwater resources consistent with federal, state, and local requirements. Each annual Part 2 GWQR addresses RCRA interim status reporting requirements regarding assessment of the horizontal and vertical extent of groundwater contamination. This report includes background information regarding the extent of groundwater and surface water contamination in the Bear Creek Regime based on the conceptual models described in the remedial investigation report (Section 2); a summary of the groundwater and surface water monitoring activities performed during CY 1995 (Section 3.0); analysis and interpretation of the CY 1995 monitoring data for groundwater (Section 4.0) and surface water (Section 5.0); a summary of conclusions and recommendations (Section 6.0); and a list of cited references (Section 7.0). Appendices contain diagrams, graphs, data tables, and summaries and the evaluation and decision criteria for data screening.

NONE

1996-08-01

324

Scarce data in hydrology and hydrogeology: Estimation and modelling of groundwater recharge for a numerical groundwater flow model in a semi-arid to arid catchment  

NASA Astrophysics Data System (ADS)

Water resources are strongly limited in semi-arid to arid regions and groundwater constitutes often the only possibility for fresh water for the population and industry. An understanding of the hydrological processes and the estimation of magnitude of water balance parameters also includes the knowledge of processes of groundwater recharge. For the sustainable management of water resources, it is essential to estimate the potential groundwater recharge under the given climatic conditions. We would like to present the results of a hydrological model, which is based on the HRU- concept and intersected the parameters of climatic conditions, topography, geology, soil, vegetation and land use to calculate the groundwater recharge. This model was primarily developed for humid area applications and has now been adapted to the regional conditions in the semi-arid to arid region. It was quite a challenge to understand the hydrological processes in the semi-arid to arid study area and to implement those findings (e.g. routing [Schulz (in prep.)]) into the model structure. Thus we compared the existing approaches for groundwater recharge estimations (chloride mass balance [Marei et. al 2000], empirical relations such as rainfall and base flow-relation [Goldschmidt 1960; Guttman 2000; Hughes 2008; Issar 1993; Lerner 1990; De Vries et. al 2002]) with the results of our numerical model. References: De Vries, J. J., I. Simmers (2002): Groundwater recharge: an overview of processes and challenges. Hydrogeology Journal (2002) 10: 5-17. DOI 10.1007/s10040-001-0171-7. Guttman, J., 2000. Multi-Lateral Project B: Hydrogeology of the Eastern Aquifer in the Judea Hills and Jordan Valley. Mekorot Water Company, Report 468, p. 36. Hughes, A. G., M. M. Mansour, N. S. Robins (2008): Evaluation of distributed recharge in an upland semi-arid karst system: the West Bank Mountain Aquifer, Middle East. Hydrogeology Journal (2008) 16: 845-854. DOI 10.1007/s10040-008-0273-6 Issar, A. S. (1993): Recharge and salination processes in the carbonate aquifers in Israel. Environmental Geology (1993) 21: 152-159. Lerner, D. N., A. S. Issar, I. Simmers (1990): Groundwater recharge: a guide to understanding and estimating natural recharge. International contributions to hydrogeology: Vol. 8. Marei, A., S. Khayat, S. Weise, S. Ghannam., M. Sbaih, S. Geyer (2010): Estimating groundwater recharge using chloride mass-balance method in the West Bank. Hydrol. Sc 01/2010; 55(5): 780-792.

Gräbe, Agnes; Schulz, Stephan; Rödiger, Tino; Kolditz, Olaf

2013-04-01

325

Oil-field disposal practices in hydrogeologic setting of Midway Sunset and Buena Vista oil fields; review of past effects, current activities, and future scenarios  

SciTech Connect

Class 2 water disposal in the Midway Sunset and Buena Vista oil fields of Kern County, California, has been by injection and infiltration from spreading ponds into the unsaturated zone, which is typically hundreds of feet thick. Water collection is mostly through an extensive tributary network of collection ditches radiating from several disposal facility locations. The purpose of this study was to evaluate the subsurface movement of fluid in the hydrogeological environment and to determine the fate of the disposed water and its long-term impact on the area.

Sengebush, R.M.; Kiser, S.C.; Greenwood, E.J.; Crozier, R.N.; Crewdson, R.A.; Wilson, M.J.; Rycerski, B.A.

1988-03-01

326

Calendar Year 1997 Annual Groundwater Monitoring Report For The Bear Creek Hydrogeologic Regime at the U.S. Department of Energy Y-12 Plant, Oak Ridge, Tennessee  

SciTech Connect

This report contains the groundwater and surface water monitoring data obtained during calendar year (CY) 1997 in compliance with the Resource Conservation and Recovery Act (RCIU) post- closure permit (PCP) for the Bear Creek Hydrogeologic Regime (Bear Creek Regime), and as otherwise required by U.S. Department of Energy (DOE) Order 5400.1. In July 1997, the Temessee Department of Environment and Conservation (TDEC) approved several modifications to the RCRA post-closure corrective action monitoring requirements specified in the PCP. This report has been prepared in accordimce with these modified requirements.

Jones, S.B.

1998-02-01

327

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

NASA Astrophysics Data System (ADS)

The main objective of this study is to provide a realistic simulation of river stage in regional river networks in order to improve the quantification of stream-aquifer exchanges and better assess the associated aquifer responses that are often impacted by the magnitude and the frequency of the river stage fluctuations. The study focuses on the Oise basin (17 000 km2, part of the 65 000 km2 Seine basin in Northern France) where stream-aquifer exchanges cannot be assessed directly by experimental methods. Nowadays numerical methods are the most appropriate approaches for assessing stream-aquifer exchanges at this scale. A regional distributed process-based hydro(geo)logical model, Eau-Dyssée, is used, which aims at the integrated modeling of the hydrosystem to manage the various elements involved in the quantitative and qualitative aspects of water resources. Eau-Dyssée simulates pseudo 3D flow in aquifer systems solving the diffusivity equation with a finite difference numerical scheme. River flow is simulated with a Muskingum model. In addition to the in-stream discharge, a river stage estimate is needed to calculate the water exchange at the stream-aquifer interface using the Darcy law. Three methods for assessing in-stream river stages are explored to determine the most appropriate representation at regional scale over 25 years (1980-2005). The first method consists in defining rating curves for each cell of a 1D Saint-Venant hydraulic model. The second method consists in interpolating observed rating curves (at gauging stations) onto the river cells of the hydro(geo)logical model. The interpolation technique is based on geostatistics. The last method assesses river stage using Manning equation with a simplified rectangular cross-section (water depth equals the hydraulic radius). Compared to observations, the geostatistical and the Manning methodologies lead to slightly less accurate (but still acceptable) results offering a low computational cost opportunity for taking into account river stage fluctuations in regional distributed process-based hydro(geo)logical models. It is an efficient way to improve the physics of the stream-aquifer interactions and better assess soil water content at the regional scale when high resolution morphological data is not available. This study offers several perspectives such as simulating the hydrodynamic behavior of alluvial wetlands and assessing the pollutants removal or release by biogeochemical processes at regional scale such as nitrate contamination. Keywords: Stream-aquifer interactions, Regional scale, Quantitative Hydrology, Hydrogeology, River stage simulations, Hydrosystem modeling

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

2012-04-01

328

Hydrogeologic, water-quality and biogeochemical data collected at a septage-treatment facility, Orleans, Cape Cod, Massachusetts, October 1988 through December 1992  

USGS Publications Warehouse

Hydrogeologic, water-quality, and biogeochemical data were collected at the site of a septage- treatment facility in Orleans, Massachusetts, from October 1988 through December 1992, where a nitrogen-rich effluent is discharged to the underlying glacial aquifer. The data were collected as part of a study done by the U.S. Geological Survey, in cooperation with the Massachusetts Department of Environmental Protection, Office of Watershed Management, to investigate the effect of effluent discharge on ground-water quality and the transport of effluent nitrogen through the aquifer. Hydrogeologic data include lithologic logs and ground-water levels. Water-quality data include chemical analyses of the treated septage effluent, of ground water at the water table beneath the infiltration beds, and of ground water throughout the aquifer. Dissolved concentrations of dinitrogen gas, nitrous oxide, and dissolved inorganic carbon also were measured. Biogeochemical data include concentrations of total ammonium and solid-phase carbon and nitrogen in aquifer sediments and sediments from the effluent-infiltration beds.

Desimone, Leslie A.; Howes, Brian Louis

1995-01-01

329

Present-day long-term deformation from GPS survey in an intraplate area (Ploemeur aquifer, French Brittany): influence of hydrological and hydrogeological processes  

NASA Astrophysics Data System (ADS)

Four years of continuous GPS measurements were performed in an intraplate area located above the crystalline aquifer of Ploemeur (French Brittany) in order to quantify the three-dimensional surface deformation and to evaluate the relationship between the ground deformation and hydrological surface and hydrogeological processes. Several processes as tide effects, ocean tide loading and tectonics were removed thanks to a differential GPS setup, short baselines and appropriated processing parameters. Time series were calculated with the GAMIT/GLOBK software and indicate a seasonal deformation on both vertical direction (up to 16 mm of total displacement) and horizontal plane (3 to 12 mm of total displacement). This sub-annual deformation is principally related to the piezometric level of the aquifer and is used to estimate some hydrogeological parameters of the aquifer and better know the behaviour of this aquifer along the time. However, some additional data of the hydrous state of the ground allows us to associate a part of the deformation to this surface process. This GPS study highlights that these two phenomena act significantly on ground motion as well on vertical direction as in horizontal plane and should be integrated in any Earth deformation survey.

Biessy, G.; Moreau, F.; Dauteuil, O.; Bour, O.

2009-12-01

330

How a geology map of the Upper Santa Maria Valley in the Southern Swiss Alps played a critical role in solving a hydrogeologic enigma  

NASA Astrophysics Data System (ADS)

Several regional-scale, fluorescent dye-tracing tests recently showed counter-intuitive, tectonically influenced, preferential ground water flow from the Piora Region via the Santa Maria Valley to the di Campo Valley. Losing rivers of the Piora Valley recharge the Triassic Piora Aquifer at an average rate of 20,000 m3/d and hydrologic budgets suggest that half of the Upper Santa Maria discharge originates from the Piora Region. The geologic map of the Upper Santa Maria Valley presented a partial solution to the hydrogeologic puzzle of the Piora Aquifer, thus facilitating construction of the AlpTransit railway tunnel (the longest on Earth). The autochthonous Lucomagno Triassic of the Gotthard Massif (cargneules), the allochthonous Frodalera-Peiden Triassic (sugar dolomites, para-gneises, quartzites, green phyllites), the Stgir Series of the Lower Jurassic (sandy limestones and quartzites), the Inferno Series of the Middle Jurassic (coarse sandstones, limestones, shales), the Coroi Series of the Upper Jurassic (black shales), the crystalline Gotthard Massif (ortho-gneises), and the northern Penninic Nappe (para- and ortho-gneises, quartzites) are the main lithologies found in the outcrops of the Upper Santa Maria Valley. The highly weathered Triassic series found in the Piora and Upper Santa Maria Valley posed a potential hydrogeologic obstacle that was overcome by tunnel drillers in early 2010, for expected tunnel service by 2012.

Otz, M. H.; Otz, I.

2010-12-01

331

Hydrogeologic controls on the transport and fate of nitrate in ground water beneath riparian buffer zones: Results from thirteen studies across the United States  

USGS Publications Warehouse

During the last two decades there has been growing interest in the capacity of riparian buffer zones to remove nitrate from ground waters moving through them. Riparian zone sediments often contain organic carbon, which favors formation of reducing conditions that can lead to removal of nitrate through denitrification. Over the past decade the National Water Quality Assessment (NAWQA) Program has investigated the transport and fate of nitrate in ground and surface waters in study areas across the United States. In these studies riparian zone efficiency in removing nitrate varied widely as a result of variations in hydrogeologic factors. These factors include (1) denitrification in the up-gradient aquifer due to the presence of organic carbon or other electron donors, (2) long residence times (>50 years) along ground-water flow paths allowing even slow reactions to completely remove nitrate, (3) dilution of nitrate enriched waters with older water having little nitrate, (4) bypassing of riparian zones due to extensive use of drains and ditches, and (5) movement of ground water along deep flow paths below reducing zones. By developing a better understanding of the hydrogeologic settings in which riparian buffer zones are likely to be inefficient we can develop improved nutrient management plans. ?? US Government 2004.

Puckett, L. J.

2004-01-01

332

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

NASA Astrophysics Data System (ADS)

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 resistivity values have been assigned to the different formations by calibrating electrical resistivity values with the borehole data. Electrical resistivity, groundwater level monitoring, and borehole and remote sensing data have been integrated in the GIS analysis to delineate the hydrogeological zoning in the study area. Suitable weights were assigned to the different features affecting the groundwater potential. The total score for a particular location is translated in terms of groundwater potential of the area. The results indicate that the southern part of the study area has a very good groundwater potential for meeting the demand of water for irrigation and domestic purposes whereas the steeply sloping area in the northern part, having high relief, has a poor groundwater potential. The resulting delineation of groundwater potential zones are in general agreement with the available yield data of the tube wells.

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

2006-06-01

333

Hydrogeology of the Waverly-Sayre area in Tioga and Chemung counties, New York and Bradford County, Pennsylvania  

USGS Publications Warehouse

The hydrogeology of a 135-square-mile area centered at Waverly, N.Y. and Sayre, Pa. is summarized in a set of five maps and a sheet of geologic sections, all at 1:24,000 scale, that depict locations of wells and test holes (sheet 1), surficial geology (sheet 2), altitude of the water table (sheet 3), saturated thickness of the surficial aquifer (sheet 4), thickness of the lacustrine confining unit (sheet 5), and geologic sections (sheet 6). The valley-fill deposits that form the aquifer system in the Waverly-Sayre area occupy an area of approximately 30 square miles, within the valleys of the Susquehanna River, Chemung River, and Cayuta Creek. The saturated thickness of the surficial aquifer, which consists of alluvium, valley-train outwash, and underlying ice-contact deposits, ranges from zero to 90 feet and is greatest in areas where (1) the outwash is underlain by ice-contact sand and gravel or (2) the outwash is overlain by alluvium and alluvial fans. Estimated transmissivity of the surficial aquifer ranges from 5,600 to 100,270 feet squared per day, and estimated hydraulic conductivity ranges from 50 feet per day for ice-contact deposits to 1,300 feet per day for well-sorted, valley-train outwash. The surficial aquifer is underlain by deposits of lacustrine sand, silt, and clay in the main valleys; these deposits reach thicknesses of as much as 150 ft and form a thick confining unit. Beneath the lacustrine silt and clay confining unit is a thin, discontinuous sand and gravel aquifer whose thickness averages 5 feet but may be as much as 30 feet locally. This confined aquifer supplies many domestic well in the area; yields average about 22 gallons per minute for 6-inch-diameter, open-ended wells. Average annual recharge to the aquifer system is estimated to be approximately 52.5 Mgal/d (million gallons per day), of which 29.7 Mgal/d is from direct precipitation, 7.6 Mgal/d is from unchanneled upland runoff that infiltrates the stratified drift along the valley wall, and 15.2 Mgal/d is from infiltration from tributary streams on the valley floor.

Reynolds, Richard J.

2002-01-01

334

Identification of Groundwater Contamination Causes Around Subway Tunnels at a Coastal Area in Korea, Using Hydrogeological and Geostatistical Analyses  

NASA Astrophysics Data System (ADS)

The cause for the deterioration of groundwater quality was identified by hydrogeological investigations and geostatisitical analyses at a coastal area in Busan, Korea. The city has many tunnels for three subway lines, for communication cables and for electrical cables under the ground. The groundwater levels of 135 wells were measured during the dry and wet seasons. The average groundwater level was 7.81 m above the mean sea level in dry season, and 9.11 m in wet season. Groundwater was sampled at 135 wells developed in shallow and deep aquifers. The average water temperature in wet season was 5.5 degrees C higher than that in dry season. The average of pH was 0.4 higher, and the average of DO was 0.6 mg/L lower in wet season. The average of EC was 136 ?S/cm higher in wet season. The total quantity of discharged groundwater from subway tunnels was 2,282,000 m3/year at the study area. It was 2.4 times the sustainable development yield of groundwater. So the groundwater level was seriously decreased at the study area. The maximum groundwater level around the subway was located at 30 ~ 32 m below the mean sea level. The deep drawdown of groundwater level brought about the inflow of sea water and river water. The groundwater around the subway lines was contaminated by sea water and the salinized water of the Suyeong River. The quality of groundwater was not reached to the standard of potable, domestic, agricultural and industrial uses. The distribution maps of groundwater level and quality were produced using a geostatistical method, kriging. The maps were very useful to find out the causes of groundwater contamination at the study area. The maps identified that sea water and river water infiltrated the inland groundwater and contaminated the groundwater around the subway lines, because the groundwater level was seriously drawdowned by the groundwater discharge from the subway tunnels. The groundwater was also contaminated by seawater intrusion at the coastal area.

Kim, D.; Kim, T.; Chung, S.; Yang, S.

2009-12-01

335

Constraining the Hydrogeology of Marine Gas Hydrate Areas in the Gulf of Mexico Using High-Resolution Geophysical Methods  

NASA Astrophysics Data System (ADS)

Previous work in our group has demonstrated that fluid (water + aqueous phase gas), gas, and energy fluxes largely control the dynamics of marine gas hydrate provinces. In the Gulf of Mexico, stratigraphic and structural complexities impart a high degree of spatial and temporal variability to these flux regimes and to the resulting concentration and distribution of gas hydrates. While this complexity poses a challenge to understanding the hydrogeology of gas hydrate zones in the Gulf, the juxtaposition of low and high flux regions and of diffuse and focused flux zones provides an important opportunity to study a range of hydrate-related environments at a compressed spatial scale. An additional advantage in this setting is related to elevated thermal gradients and high advective transport rates, which lead to the formation and long-term stability of gas hydrate at the seafloor or in the uppermost meters of sediment in some locations. Gulf of Mexico gas hydrates are therefore sometimes highly accessible to geophysical methods that yield information about the shallowest part of the sedimentary column. In this study, we apply high-resolution geophysical methods to image fluid conduits, describe the thermal state of the gas hydrate reservoir, constrain advective fluid flux rates, and map lateral variability in flow regimes in 3 regions targeted for possible future gas hydrates drilling in the Gulf of Mexico: Mississippi Canyon, Bush Hill (GC 185), and Garden Banks 425. Using limited Chirp seismic data, we determine the location of stratigraphic and structural features that focus fluid flow or trap fluids and gas, processes that both contribute to increased concentrations of gas hydrate under many circumstances. In a relatively novel application of traditional marine heat flow methods, we also report the results of high-resolution surveys that exploit the inherent accuracy of the instrumentation to map lateral changes in thermal regimes on multiple spatial scales as one tool for constraining advective flux variations. Using a transient model for the evolution of permeability in fractures and porous media in gas hydrate zones, we incorporate field constraints to predict the first-order distribution and concentration of gas hydrate in sediments at the three potential drill sites.

Ruppel, C.; Brooks, J.; O'Brien, T.; Lizarralde, D.; Nimblett, J.

2002-12-01

336

Characterizing the Hydrogeology and Surface Waters of a Select Portion of the Permian Basin Using an Arc Hydro Groundwater Database  

NASA Astrophysics Data System (ADS)

Atmospheric levels of anthropogenic CO2 have increased from a pre industrial level of 280 parts per million to a 1999 concentration of over 365 parts per million, largely due to expanding use of fossil fuels for human energy needs. Current levels are the highest observed in over 350,000 years. The desire to stabilize atmospheric concentrations of CO2 supports research on and development of technologies that will achieve this end. Sequestration of carbon in geologic formations is one such technology that is actively being pursued. Of particular interest is the Permian Basin of eastern Texas and southeastern New Mexico, a basin with substantial saline and brine aquifers that might be very suitable for carbon sequestration, and also a basin that has been producing oil and gas for well over 100 years, a process which utilizes CO2 injection for enhanced recovery. Understanding the interactions between those portions of the Permian Basin proposed for CO2 sequestration and those portions currently utilized as a water supply (i.e., Pecos River and freshwater aquifers) is a critical component of the R&D in this area because of the reliance of a large agricultural community and other delicate legal and environmental balances prevailing in this region. The main purpose of this study is to create a detailed hydrological model with emphasis on hydrogeology and surface waters of a select portion of the Permian Basin, delineated by the Sacramento Mountains to the west and the Delaware Basin to the east, with the long term goal that this study will be one component of a total basin characterization and evaluation. Arc Hydro groundwater data model framework is used to create a database of the study area. The construction of this database is an initial step in the integration of the plethora of oil, gas, and water databases (e.g., IHS Database, New Mexico Subsurface and Core Libraries, and WATERS Database), and provides a platform for the addition of hydrological and geological data (e.g., from the New Mexico Bureau of Geology's Sacramento Mountains Project). The database is then coupled with a numerical model used to explore groundwater surface water interactions and aquifer connectedness at both the regional and site scale, with particular emphasis placed on those phenomena elucidating the interdependencies between the Pecos Slope and the Delaware Basin. This application of the Arc Hydro groundwater data model will be expanded upon and its predictive capabilities further developed such that the effects of CO2 sequestration in the Capitan Reef aquifer can be evaluated.

Morse, J. T.; McPhearson, B. J.; Land, L. A.

2006-12-01

337

An hydrogeological web-gis platform for water resource management and consensus reaching at the basin scale  

NASA Astrophysics Data System (ADS)

Water resource management at the basin scale involves a variety of uses of the resource and a multiplicity of different scenarios concerning the schematization of the hydrographical network, representing an interesting issue, also because it is becoming very actual in Mediterranean countries where water contributions to river basins are more and more concentrated in short wet periods followed by longer periods of droughts. When severe droughts occur, the problem can be split depending whether or not large reservoirs are present in the basin. In the first case, the problem mainly regards long term management of the stored water; in the second case, emergency interventions must be taken into consideration. However, a management involves three fundamental stages: the first is the evaluation of the available water resources; the second is the integrated management of these resources, with particular attention given to hypotheses for developments in water usage and the occurrence of critical deficit periods and the third is the consensus reaching amongst all the parties concerned. For these purposes an integrated WEB-BASED system has been designed and developed starting from the principles of an integrated water resources management, information and methodologies sharing and consensus reaching. The system is therefore composed of three logical areas: the first of the three is the modelling engine for the evaluation of hydrologic indexes and flow duration curves that, starting from the data contained in a wide validated database of hydrogeological, geospatial and administrative information and with the support of a Grass GIS system for terrain analysis, is capable of providing an estimate of the available resource. The second one is represented by a simulation and managing model that allows the analysis of different and alternative scenarios of water allocation and distribution amongst the uses present in the basin. Finally a user friendly WEB interface grants access not only to the data and information but also to the simulation, evaluation and managing modules implemented so that stakeholders and facilitators can discuss on the basis of shared data, commonly agreed management hypothesis, evaluation methodologies and the set of alternative solutions provided by the system. Therefore, the aim of this project is not only to provide a decision support system per se, but an integrated platform in the effort of sharing the entire decisional process so that more effective water resources management plans could be developed and possible controversies could be prevented. In the present work, the discussion of the designing and technological issues is followed by a case study for the validation of this platform applied to the Upper Tiber River, a large area with many agricultural and municipal water users, and several areas of considerable environmental interest, where two reservoirs (about 150-200 Mcm each) are located.

Pierleoni, A.; Bellezza, M.; Casagrande, L.; Casadei, S.

2009-04-01

338

Hydrogeological aspects and environmental concerns of the New Valley Project, Western Desert, Egypt, with special emphasis on the southern area  

NASA Astrophysics Data System (ADS)

The New Valley Project has been given much attention in the past 20 years especially from the hydrogeological point of view concerning groundwater utilization for the reclamation of a large area of the Western Desert. Lithological, petrophysical, and petrographical studies were conducted on four wells south of Beris Oasis, namely Beris 20, Beris 15, Beris 14, and Beris 13, and are defined by latitudes 24°25'E and 24°35'E and longitudes 30°30'N and 30°46'N. The Nubian sedimentation is of Posttectonic deposition that took place over the uplifted Precambrian granitic basement and is Lower Cretaceous, whereas the upper most variegated shales of the cap rock are Upper Cretaceous. The Nubian sandstones in the area south of Beris Oasis contain hematitic stains and/or fine granular authigenic hematite, thin laminae of brown ferruginous quartzite is also recorded denoting oxidizing conditions in the basin of deposition. Thin streaks of carbonaceous shales are met with in different depths to the south of Beris area, may be taken to denote oscillations in the sea level and accordingly its depths, and are responsible for the change in the oxidation-reduction potential during the deposition of the corresponding beds. Lithologic logs were interpreted together with the electric and micro-logs for adjustment of the shale breaks and showed that there are five water-bearing zones, named from bottom to top: A, B, C, D, and E, and are mainly unfossiliferous orthoquartzites, separated from each other by impervious beds of siltstones, shales, and clays of varying thicknesses. This zoning had been found valid in other parts of the Kharga Oases and could be applied locally in the Kharga Oases area. Mechanical analysis was performed mainly on 39 samples, of which 18 were core samples and 21 were cuttings, that were raised from four wells dug in the area south of Beris Oasis, Kharga Oases. Porosity and permeability tests were carried out on the 18 core samples only. The implication of these data on the environment of deposition of the Nubia Sandstone is discussed. Petrographic examination of a thin section of the subsurface Nubia sandstones in the South of Beris Oasis showed that the lithified rocks fall into three types depending on the nature of cement being, silicious or ferruginous, and on the amount of primary matrix, which at present is reorganized into iron oxides, microquartz, and muscovite flakes, thus reaching the phyllomorphic stage of diagensis. Rounding of the quartz grains shows that transportation had a minor effect on the grain morphology and favor a fluviatile transporting agent.

Assaad, Fakhry A.

1988-12-01

339

A hydrogeological study of the confined aquifers below the Boom Clay in NE-Belgium: combining a piezometric analysis with groundwater modelling  

NASA Astrophysics Data System (ADS)

For more than 35 years, SCKCEN has been investigating the possibility of high-level and/or long-lived radioactive waste disposal in the Boom Clay in north-eastern Belgium. This research, defined in the long term management programme for high-level and/or long-lived waste of ONDRAF/NIRAS, includes studying the regional hydrogeology of the aquifer systems surrounding the Boom Clay. In this context, a hydrogeological study of the confined aquifers below the Boom Clay was performed. To properly address the conceptual uncertainties related to the poorly characterized domain featuring large uncertainty in the forcing data, a combination of a piezometric data analysis and hydrogeological modelling was used. The study area represents the confined part of the groundwater system located stratigraphically below the Boom Clay in NE-Belgium. This so-called deep aquifer system includes, with increasing depth, parts of the Oligocene aquifer, the Bartoon aquitard system and the Ledo-Paniselian-Brusselian aquifer. Due to the considerable pumping from these aquifers in combination with a limited recharge to the deep aquifer system, a gradual decrease in groundwater levels has been observed in more than 30-year piezometric records. The analysis of the piezometry of the confined deep aquifer system allowed gaining more insight on the system response to the intensive pumping. Since the Oligocene aquifer has a significantly lower permeability compared to the Ledo-Paniselian-Brusselian aquifer, the Oligocene pumping triggers only local effects on groundwater levels. Hence, the regional effects (constant decrease of groundwater levels) in the Oligocene aquifer are presumably caused by pumping in the Ledo-Paniselian-Brusselian aquifer, whereby the hydraulically isolating Maldegem Formation (Bartoon aquitard) dampens these effects. The amount of this dampening is given by the spatial distribution of the hydraulic properties of the Maldegem Formation and/or its variable thickness. For the piezometers located in the Ledo-Paniselian-Brusselian aquifer, we see that although the pumping is concentrated in the south, it causes the water level to decrease far northwards, which implies a higher hydraulic conductivity of this aquifer than the Oligocene aquifer. A transient hydrogeological model was constructed for the area in order to confirm the findings of the piezometric analysis and to analyze the regional flow processes occurring in the deep aquifer system. Since groundwater pumping is the most important process affecting the groundwater flow in the deep aquifer system, we reconstructed the pumping history in the Oligocene aquifer, the Bartoon aquitard system and the Ledo-Paniselian-Brusselian aquifer as far as possible into the past. The detailed geometry of the Oligocene aquifer and Bartoon aquitard system was introduced in the model, implying a variable thickness of the clay layers in these formations. The model was calibrated using an automated calibration algorithm and is able to reproduce satisfactorily the general trends in the observed groundwater level data. The most sensitive parameters of the model are the pumping amount, the hydraulic conductivity of the Ledo-Paniselian-Brusselian aquifer and the vertical hydraulic conductivity of the clay layers in the Oligocene aquifer and the Bartoon aquitard system. The outcome of the hydrogeological modelling confirms the results of the piezometric data analysis and is further used for assessment of the regional flows in the deep aquifer system.

Vandersteen, Katrijn; Gedeon, Matej

2013-04-01

340

Assessment of hydrogeologic conditions with emphasis on water quality and wastewater injection, southwest Sarasota and West Charlotte counties, Florida  

USGS Publications Warehouse

The 250-square-mile area of southwest Sarasota and west Charlotte Counties is underlain by a complex hydrogeologic system having diverse ground-water quality. The surficial and intermediate aquifer systems and the Upper Floridan aquifer of the Floridan aquifer system contain six separate aquifers, or permeable zones, and have a total thickness of about 2,000 feet. Water in the clastic surficial aquifer system is potable and is tapped by hundreds of shallow, low-yielding supply wells. Water in the mixed clastic and carbonate intermediate aquifer system is potable in the upper part, but in the lower part, because of increasing salinity, it is used primarily for reverse-osmosis desalinization feed water and irrigation. Within the Upper Floridan aquifer, limestone and dolomite of the Suwannee permeable zone are tapped by irrigation and reverse-osmosis supply wells. The underlying, less permeable limestone of the Suwannee-Ocala semiconfining unit generally encompasses the transition zone between freshwater and very saline water. Interbedded limestone and dolomite of the Ocala-Avon Park moderately permeable zone and Avon Park highly permeable zone compose the deep, very saline injection zone. Potential ground-water contamination problems include flooding by storm tides, upward movement of saline water toward pumping centers by natural and induced leakage or through improperly constructed and abandoned wells, and lateral and vertical movement of treated sewage and reverse-osmosis wastewater injected into deep zones. Effects of flooding are evident in coastal areas where vertical layering of fresh and saline waters is observed. Approximately 100 uncontrolled flowing artesian wells that have interaquifer flow rates as high as 350 gallons per minute have been located and scheduled for plugging by the Southwest Florida Water Management District--in an attempt to improve ground-water quality of the shallow aquifers. Because each aquifer or permeable zone has unique head and water-quality characteristics, construction of single-zone wells would eliminate cross-contamination and borehole interflow. Such a program, when combined with the plugging of shallow-cased wells having long open-hole intervals connecting multiple zones, would safeguard ground-water resources in the study area. The study area encompasses seven wastewater injection sites that have a projected capacity for injecting 29 million gallons per day into the zone 1,100 to 2,050 feet below land surface. There are six additional sites within 20 miles. The first well began injecting reverse-osmosis wastewater in 1984, and since then, other wells have been drilled and permitted for injection of treated sewage. A numerical model was used to evaluate injection-well design and potential for movement of injected wastewater within the hydrogeologic framework. The numerical model was used to simulate injection through a representative well at a rate of 1 million gallons per day for 10 years. In this simulation, a convection cell developed around the injection well with the buoyant fresh injectant rising to form a lens within the injection zone below the lower Suwannee-Ocala semiconfining unit. Around an ideal, fully penetrating well cased 50 feet into the injection zone and open from a depth of 1,150 feet to 2,050 feet, simulations show that the injectant moves upward to a depth of 940 feet, forms a lens about 600 feet thick, and spreads radially outward to a distance of about 2,300 feet after 10 years. Comparison simulations of injection through wells having open depth intervals of 1,150 to 1,400 feet and 1,450 to 2,050 feet demonstrate that such changes in well construction have little effect on the areal spread of the injectant lens or the rate of upward movement. Simulations also indicate that reverse-osmosis wastewater injected beneath a supply well field, where water levels above the semiconfining unit are lowered 20 feet by pumping, would move upward after 10 years to a de

Hutchinson, C. B.

1992-01-01

341

Inverse problem in hydrogeology  

NASA Astrophysics Data System (ADS)

The state of the groundwater inverse problem is synthesized. Emphasis is placed on aquifer characterization, where modelers have to deal with conceptual model uncertainty (notably spatial and temporal variability), scale dependence, many types of unknown parameters (transmissivity, recharge, boundary conditions, etc.), nonlinearity, and often low sensitivity of state variables (typically heads and concentrations) to aquifer properties. Because of these difficulties, calibration cannot be separated from the modeling process, as it is sometimes done in other fields. Instead, it should be viewed as one step in the process of understanding aquifer behavior. In fact, it is shown that actual parameter estimation methods do not differ from each other in the essence, though they may differ in the computational details. It is argued that there is ample room for improvement in groundwater inversion: development of user-friendly codes, accommodation of variability through geostatistics, incorporation of geological information and different types of data (temperature, occurrence and concentration of isotopes, age, etc.), proper accounting of uncertainty, etc. Despite this, even with existing codes, automatic calibration facilitates enormously the task of modeling. Therefore, it is contended that its use should become standard practice. L'état du problème inverse des eaux souterraines est synthétisé. L'accent est placé sur la caractérisation de l'aquifère, où les modélisateurs doivent jouer avec l'incertitude des modèles conceptuels (notamment la variabilité spatiale et temporelle), les facteurs d'échelle, plusieurs inconnues sur différents paramètres (transmissivité, recharge, conditions aux limites, etc.), la non linéarité, et souvent la sensibilité de plusieurs variables d'état (charges hydrauliques, concentrations) des propriétés de l'aquifère. A cause de ces difficultés, le calibrage ne peut êtreséparé du processus de modélisation, comme c'est le cas dans d'autres cas de figure. Par ailleurs, il peut être vu comme une des étapes dans le processus de détermination du comportement de l'aquifère. Il est montré que les méthodes d'évaluation des paramètres actuels ne diffèrent pas si ce n'est dans les détails des calculs informatiques. Il est montré qu'il existe une large panoplie de techniques d'inversion : codes de calcul utilisables par tout-un-chacun, accommodation de la variabilité via la géostatistique, incorporation d'informations géologiques et de différents types de données (température, occurrence, concentration en isotopes, âge, etc.), détermination de l'incertitude. Vu ces développements, la calibration automatique facilite énormément la modélisation. Par ailleurs, il est souhaitable que son utilisation devienne une pratique standardisée. Se sintetiza el estado del problema inverso en aguas subterráneas. El énfasis se ubica en la caracterización de acuíferos, donde los modeladores tienen que enfrentar la incertidumbre del modelo conceptual (principalmente variabilidad temporal y espacial), dependencia de escala, muchos tipos de parámetros desconocidos (transmisividad, recarga, condiciones limitantes, etc), no linealidad, y frecuentemente baja sensibilidad de variables de estado (típicamente presiones y concentraciones) a las propiedades del acuífero. Debido a estas dificultades, no puede separarse la calibración de los procesos de modelado, como frecuentemente se hace en otros campos. En su lugar, debe de visualizarse como un paso en el proceso de enten dimiento del comportamiento del acuífero. En realidad, se muestra que los métodos reales de estimación de parámetros no difieren uno del otro en lo esencial, aunque sí pueden diferir en los detalles computacionales. Se discute que existe amplio espacio para la mejora del problema inverso en aguas subterráneas: desarrollo de códigos amigables alusuario, acomodamiento de variabilidad a través de geoestadística, incorporación de información geológica y diferentes tipos de datos (temperatura, presencia y co

Carrera, Jesús; Alcolea, Andrés; Medina, Agustín; Hidalgo, Juan; Slooten, Luit J.

2005-03-01

342

Translational ecology for hydrogeology.  

PubMed

Translational ecology-a special discipline aimed to improve the accessibility of science to policy makers-will help hydrogeologists contribute to the solution of pressing environmental problems. Patterned after translational medicine, translational ecology is a partnership to ensure that the right science gets done in a timely fashion, so that it can be communicated to those who need it. PMID:23837514

Schlesinger, William H

2013-07-09

343

Hydrogeologic framework refinement, ground-water flow and storage, water-chemistry analyses, and water-budget components of the Yuma area, southwestern Arizona and southeastern California  

USGS Publications Warehouse

The ground-water and surface-water system in the Yuma area in southwestern Arizona and southeastern California is managed intensely to meet water-delivery requirements of customers in the United States, to manage high ground-water levels in the valleys, and to maintain treaty-mandated water-quality and quantity requirements of Mexico. The following components in this report, which were identified to be useful in the development of a ground-water management model, are: (1) refinement of the hydrogeologic framework; (2) updated water-level maps, general ground-water flow patterns, and an estimate of the amount of ground water stored in the mound under Yuma Mesa; (3) review and documentation of the ground-water budget calculated by the Bureau of Reclamation, U.S. Department of the Interior (Reclamation); and (4) water-chemistry characterization to identify the spatial distribution of water quality, information on sources and ages of ground water, and information about the productive-interval depths of the aquifer. A refined three-dimensional digital hydrogeologic framework model includes the following hydrogeologic units from bottom to top: (1) the effective hydrologic basement of the basin aquifer, which includes the Pliocene Bouse Formation, Tertiary volcanic and sedimentary rocks, and pre-Tertiary metamorphic and plutonic rocks; (2) undifferentiated lower units to represent the Pliocene transition zone and wedge zone; (3) coarse-gravel unit; (4) lower, middle, and upper basin fill to represent the upper, fine-grained zone between the top of the coarse-gravel unit and the land surface; and (5) clay A and clay B. Data for the refined model includes digital elevation models, borehole lithology data, geophysical data, and structural data to represent the geometry of the hydrogeologic units. The top surface of the coarse-gravel unit, defined by using borehole and geophysical data, varies similarly to terraces resulting from the down cutting of the Colorado River. Clay A is nearly the same as the previous conceptual hydrogeologic model definition (Olmsted and others, 1973), except for a minor westward extension from the city of Yuma. Clay B is extended to the southerly international boundary and increased in areal extent by about two-thirds of the original extent (Olmsted and others, 1973). The other hydrogeologic units generally are the same as in the previous conceptual hydrogeologic model. Before development, the Colorado and Gila Rivers were the sources of nearly all the ground water in the Yuma area through direct infiltration of water from river channels and annual overbank flooding. After construction of upstream reservoirs and clearing and irrigation of the floodplains, the rivers now act as drains for the ground water. Ground-water levels in most of the Yuma area are higher now than they were in predevelopment time. A general gradient of ground-water flow toward the natural discharge area south of the Yuma area still exists, but many other changes in flow are evident. Ground water in Yuma Valley once flowed away from the Colorado River, but now has a component of flow towards the river and Mexicali Valley. A ground-water mound has formed under Yuma Mesa from long-term surface-water irrigation; about 600,000 to 800,000 acre-ft of water are stored in the mound. Ground-water withdrawals adjacent to the southerly international boundary have resulted in water-level declines in that area. The reviewed and documented water budget includes the following components: (1) recharge in irrigated areas, (2) evapotranspiration by irrigated crops and phreatophytes, (3) ground-water return flow to the Colorado River, and (4) ground-water withdrawals (including those in Mexicali Valley). Recharge components were calculated by subtracting the amount of water used by crops from the amount of water delivered. Evapotranspiration rates were calculated on the basis of established methods, thus were appropriate for input to the ground-wate

Dickinson, Jesse E.; Land, Michael; Faunt, Claudia C.; Leake, S.A.; Reichard, Eric G.; Fleming, John B.; Pool, D. R.

2006-01-01

344

Geophysical and hydrogeologic investigations of two primary alluvial aquifers embedded in the southern San Andreas fault system: San Bernardino basin and upper Coachella Valley  

NASA Astrophysics Data System (ADS)

This study of alluvial aquifer basins in southern California is centered on observations of differential surface displacement and the search for the mechanisms of deformation. The San Bernardino basin and the Upper Coachella Valley aquifers are bound by range fronts and fault segments of the southern San Andreas fault system. I have worked to quantify long-term compaction in these groundwater dependent population centers with a unique synthesis of data and methodologies using Interferometric Synthetic Aperture Radar (InSAR) and groundwater data. My dissertation contributes to the understanding of alluvial aquifer heterogeneity and partitioning. I model hydrogeologic and tectonic interpretations of deformation where decades of overdraft conditions and ongoing aquifer development contribute to extreme rapid subsidence. I develop the Hydrogeologic InSAR Integration (HII) method for the characterization of surface deformation in aquifer basins. The method allows for the separation of superimposed hydraulic and/or tectonic processes in operation. This formalization of InSAR and groundwater level integration provides opportunities for application in other aquifer basins where overdraft conditions may be causing permanent loss of aquifer storage capacity through compaction. Sixteen years of SAR data for the Upper Coachella Valley exhibit rapid vertical surface displacement (? 48mm/a) in sharply bound areas of the western basin margin. Using well driller logs, I categorize a generalized facies analysis of the western basin margin, describing heterogeneity of the aquifer. This allowed for assessment of the relationships between observed surface deformation and sub-surface material properties. Providing the setting and context for the hydrogeologic evolution of California's primary aquifers, the mature San Andreas transform fault is studied extensively by a broad range of geoscientists. I present a compilation of observations of creep, line integrals across the Pacific-North America Plate Boundary, and strain tensor volumes for comparison to the Working Group 2007 (UCERF 2) seismicity-based deformation model. I find that the moment accumulation across the plate boundary is consistent with the deformation model, suggesting fault displacement observations within the plate boundary zone accurately capture the strain across the plate boundary. This dissertation includes co-authored materials previously published, and also includes unpublished work currently under revisions for submission to a technical journal.

Wisely, Beth Ann

345

Hydrogeological and hydrochemical framework of Upper Awash River basin, Ethiopia: With special emphasis on inter-basins groundwater transfer between Blue Nile and Awash Rivers  

NASA Astrophysics Data System (ADS)

Integrated approach has been used to investigate the hydrogeological framework of a complex fractured volcanic aquifer system in the Upper Awash River basin located at the western shoulder of the Ethiopian Rift. The groundwater flow system and mechanism of recharge of different aquifers have been studied using conventional hydrogeological field investigations, hydrochemistry, and isotope hydrology. Litho-hydrostratigraphic relationships were constructed from lithologic logs obtained from exploratory drilling of deep boreholes. The result indicates quite complex flow pattern and hydraulic characteristics of the different volcanic aquifers. The litho-hydrostratigraphic correlation indicates that the permeable and porous scoraceous lower basaltic aquifer is extended laterally all the way from the Blue Nile Plateau to the study area. New evidences have also emerged on the inter-basin groundwater transfer. Two distinct regional basaltic aquifers (upper and lower) are identified showing distinct hydrochemical and isotopic signatures. In the southern part of the study area the upper and lower aquifers form one unconfined regional aquifer system. In the northern and central part of the basin, it appears that the two systems are separated by regional aquiclude forming confined aquifers, in places with artesian wells. The groundwater from the deep exploratory wells (>250 m) tapping the lower basaltic aquifer and wells located in the south were found to be moderately mineralized (TDS: 400-600 mg/l), with relatively depleted stable isotope composition and with almost zero tritium. In contrast, the upper shallow aquifer has lesser ionic concentration, more isotopically enriched. Evidences from the different methods clearly indicate inter-basin groundwater transfer from the Blue Nile basin to the Upper Awash basin. The evidences also converge to testify common origin of recharge, presence of hydraulic connectivity for systems tapping the lower basaltic aquifer. This has enormous practical implication in finding large groundwater reserve at a greater depth that can solve the current water supply problems of the community including the capital Addis Ababa. It will also have important role in finding more regional aquifers along the plateau-rift margins in many areas having similar hydrogeological setup as the study area.

Yitbarek, Andarge; Razack, Moumtaz; Ayenew, Tenalem; Zemedagegnehu, Engida; Azagegn, Tilahun

2012-04-01

346

Linking local riverbed flow patterns and pore-water chemistry to hydrogeologic and geomorphic features across scales  

NASA Astrophysics Data System (ADS)

The groundwater-surface water interface (GSI) is a critical environmental hotspot, a key area influencing the fate of carbon, nutrients and contaminants of surface and subsurface origin, and a zone of ecological importance. Policy seeking to mitigate issues relating to dissolved contaminants and to improve stream health, increasingly recognizes its significance, particularly in the context of integrated management of streams and aquifers. Techniques assessing riverbed flow and solute patterns are often limited to the local scale. When related to the multi-scale pattern of hydrogeologic and geomorphic features controlling stream, hyporheic and groundwater fluxes, they can improve larger scale predictions of flow and solute behaviour at the GSI. This study develops a conceptual model of riverbed flow and solute patterns, and tests it in a 4th order stream in the UK. It assesses the interaction between large scale subsurface flowpaths, driven by the distribution of bedrock outcrops, and the expansion and closure of alluvial deposits, and small-scale hyporheic flowpaths, driven by riffle-pool sequences. It uses two networks of riverbed mini-piezometers and multi-level samplers: network 1, across fifteen sites in a 7.2 km length of river in unconstrained (open alluvial valley), asymmetric (bedrock outcropping on one bank) and constrained (bedrock on both banks) contexts; and network 2, across six riffle-pool sequences in a 350-m reach, at the transition between asymmetric/unconstrained and constrained contexts. Subsurface flowpaths and stream-water infiltration were deduced by relating vertical exchange fluxes to stream and pore-water patterns of conservative natural tracers. Biogeochemical processes were highlighted using reactive natural tracers. At network 2, measurements of surface water profiles and riverbed coring were also undertaken, and dissolved metal concentrations in the first 15 cm of sediments assessed using gel probes. Network 1 was sampled twice. Monthly head measurements and seasonal pore-water sampling were undertaken at network 2. Results from network 1 showed the combined influence of valley type and riffle-pool sequences on riverbed flow and solute patterns. In asymmetric and unconstrained contexts, stream water infiltrated deeply in the riverbed in riffles. In pools, a vertical stratification of hydrochemically distinct flowpaths, often disconnected hydrologically from the stream, was observed. Biogeochemical reactions were more developed in pools. In constrained context, riverbed pore-water was dominated by upwelling subsurface flowpaths displaying a low vertical variability of hydrochemistry. Biogeochemical reactions were not apparent, and stream water infiltration was limited to shallow depth in riffle context. The replicability of these patterns with regards to local conditions (groundwater discharge, surface water profile and riverbed permeability) will be discussed at network 2. Finally, implications of the conceptual model for the near-bed ecosystem will be illustrated by assessing the bioavailability of metals in the shallow riverbed. This work will help to better design monitoring strategies aiming to consider the control of the GSI on solute fate across scales.

Ibrahim, T. G.; Thornton, S.; Surridge, B.; Wainwright, J.

2009-12-01

347

Hydrogeology and water quality of the Dublin and Midville aquifer systems at Waynesboro, Burke County, Georgia, 2011  

USGS Publications Warehouse

The hydrogeology and water quality of the Dublin and Midville aquifer systems were characterized in the City of Waynesboro area in Burke County, Georgia, based on geophysical and drillers’ logs, flowmeter surveys, a 24-houraquifer test, and the collection and chemical analysis of water samples in a newly constructed well. At the test site, the Dublin aquifer system consists of interlayered sands and clays between depths of 396 and 691 feet, and the Midville aquifer system consists of a sandy clay layer overlying a sand and gravel layer between depths of 728 and 936 feet. The new well was constructed with three screened intervals in the Dublin aquifer system and four screened intervals in the Midville aquifer system. Wellbore-flowmeter testing at a pumping rate of 1,000 gallons per minute indicated that 52.2 percent of the total flow was from the shallower Dublin aquifer system with the remaining 47.8 percent from the deeper Midville aquifer system. The lower part of the lower Midville aquifer (900 to 930 feet deep), contributed only 0.1 percent of the total flow. Hydraulic properties of the two aquifer systems were estimated using data from two wellbore-flowmeter surveys and a 24-hour aquifer test. Estimated values of transmissivity for the Dublin and Midville aquifer systems were 2,000 and 1,000 feet squared per day, respectively. The upper and lower Dublin aquifers have a combined thickness of about 150 feet and the horizontal hydraulic conductivity of the Dublin aquifer system averages 10 feet per day. The upper Midville aquifer, lower Midville confining unit, and lower Midville aquifer have a combined thickness of about 210 feet, and the horizontal hydraulic conductivity of the Midville aquifer system averages 6 feet per day. Storage coefficient of the Dublin aquifer system, computed using the Theis method on water-level data from one observation well, was estimated to be 0.0003. With a thickness of about 150 feet, the specific storage of the Dublin aquifer system averages about 2×10-6 per foot. Water quality of the Dublin and Midville aquifer systems was characterized during the aquifer test on the basis of water samples collected from composite well flow originating from five depths in the completed production well during the aquifer test. Samples were analyzed for total dissolved solids, specific conductance, pH, alkalinity, and major ions. Water-quality results from composite samples, known flow contribution from individual screens, and a mixing equation were used to calculate water-quality values for sample intervals between sample depths or below the bottom sample depth. With the exception of iron and manganese, constituent concentrations of water from each of the sampled intervals and total flow from the well were within U.S. Environmental Protection Agency primary and secondary drinking-water standards. Water from the bottommost sample interval in the lower part of the lower Midville aquifer (900 to 930 feet) contained manganese and iron concentrations of 59.1 and 1,160 micrograms per liter, respectively, which exceeded secondary drinking-water standards. Because this interval contributed only 0.1 percent of the total flow to the well, water quality of this interval had little effect on the composite well water quality. Two other sample intervals from the Midville aquifer system and the total flow from both aquifer systems contained iron concentrations that slightly exceeded the secondary drinking-water standard of 300 micrograms per liter.

Gonthier, Gerard J.

2013-01-01

348

Large sedimentary aquifer system and sustainable management: investigations of hydrogeological and geochemical variations in Eocene sand aquifer, south western France  

NASA Astrophysics Data System (ADS)

In the sedimentary Aquitaine Basin, the Eocene Sand Aquifer system, mostly confined, represents strategic resources for drinking water, irrigation, gas storage and geothermal resources. Therefore, its quantity and quality issues are essential for the sustainable management in this large region that extends over 116,000 km2 (i.e. one-fifth of the French territory). The Eocene Sand Aquifer system comprises at least five aquifers: Paleocene, Eocene infra-molassic sands, early Eocene, middle Eocene, and late Eocene. The extension and thickness of Eocene aquifer layers and negative confined layers vary throughout the basin, from several tens of metres to a hundred metres. The deposit sequences characterizing the Eocene Aquifer System are progradational westward from detrital deposits to carbonates. Eocene sands and Eocene limestones are hydraulically connected and covered by an aquiclude of up to several hundred metres thick of molassic sediments. The groundwater recharge is assumed to occur through the Eocene outcrops located in the north and north-east, and in the south east in contact with the Montagne Noire as well as by vertical leakage from the upper and lower aquifers. Another recharge is suspected in the south near the Petites Pyrenees. According to isotopic data, both present-day recharge and old recharge (16-35 ky) can be evidenced. The north and south evolutions of the piezometric surface are different. In the north, because of years of pumping, a trough in the potentiometric surface has been formed. The piezometric decline is roughly one meter per year in the depression centre. In the south, the decline of the water table is roughly half a meter per year. Furthermore, in the south part, around two sites of gas storage, significant fluctuations of the potentiometric surface are superimposed to the variations resulting from water abstraction, due to the injection and abstraction of gas. However, a major difficulty for the sustainable management is the lack of knowledge in the central part of this area, due to a lack of geological prospection data. The complex geological structures (anticlines, synclines, faults, grabens, horsts, salt diapirs) must also be taken into account in order to develop modelling approaches. In addition to the quantitative aspect, the quality of waters induces others management difficulties. The geochemical analyses reflect the influence of the lithologies (e.g. carbonates, silicates and evaporites). The highest mineralization is generally encountered in water draining evaporitic formations; but can also be observed in areas where such lithologies are not yet observed. Thus, many boreholes used for drinking water supply present waters with sulphate and fluoride concentrations exceeding the drinking water standards, while secondary resource for dilution is not always present. Coupling hydrogeological, geological and geochemical approaches may help to better understand and constrain management of this complex aquifer system.

Malcuit, E.; Negrel, P. J.; Petelet-Giraud, E.; Durst, P.

2010-12-01

349

Hydrostratigraphic characterization of intergranular and secondary porosity in part of the Cambrian sandstone aquifer system of the cratonic interior of North America: Improving predictability of hydrogeologic properties  

USGS Publications Warehouse

The Upper Cambrian interval of strata in the cratonic interior of North America has a long history of inconsistent hydrogeologic classification and a reputation for marked and unpredictable variability in hydraulic properties. We employed a hydrostratigraphic approach that requires hydraulic data to be interpreted within the context of a detailed characterization of the distribution of porosity and permeability to arrive at a better understanding of these rocks. As a first step, we constructed a framework of hydrostratigraphic attributes that is a depiction of the spatial distribution of both rock matrix and secondary porosity, independent of hydraulic data such as pumping-test results. The locations of hundreds of borehole geophysical logs and laboratory measurements of rock sample matrix porosity and permeability were mapped on detailed (mostly 1:100,000 or greater), conventional, lithostratigraphic maps. Stratigraphic cross-sections, based on hundreds of natural gamma logs and thousands of water-well records, have provided a markedly improved depiction of the regional distribution of rock matrix hydrostratigraphic components. Borehole, core and outcrop observations of secondary porosity were also tied to detailed stratigraphic sections and interpolated regionally. As a second step, we compiled and conducted a large number of hydraulic tests (e.g., packer tests and borehole flowmeter logs) and analyzed thousands of specific capacity tests (converted to hydraulic conductivity). Interpretation of these data within the context of the hydrostratigraphic attributes allowed us to produce a new hydrogeologic characterization for this stratigraphic interval and gain important insights into geologic controls on hydraulic variability. There are a number of assumptions in herent in most previous hydrogeologic investigations of these strata, such as equivalency of lithostratigraphic and hydrogeologic units and the dominance of intergranular flow in sandstone, that are not consistent with our results. A particularly important outcome of our study is recognition of regionally extensive bedding-plane fracture clusters. Such exceptionally high hydraulic conductivity features dominate the hydraulics of aquifers and confining units in these siliciclastic-dominated strata, including within intervals consisting largely of friable sandstone with high intergranular conductivity. Furthermore, our results provide some measure of fracture predictability, by correlating their abundance and hydraulic importance to specific stratigraphic positions and particular depths of burial beneath younger bedrock. A discrete, consistent stratigraphic interval of fine-grained siliciclastic beds also is apparently resistant to the development of vertically interconnected fractures, making the location of this regionally extensive confining unit predictable. Our more rigorous approach of interpreting typical hydraulic tests as well as relatively new techniques of borehole flowmeter logging, within the context of a hydrostratigraphic framework, results in improved definition of individual aquifers and confining units. It also enables quantification of their hydraulic properties, which leads to improved prediction of groundwater flow paths and time-of-travel. ?? 2005 Elsevier B.V. All rights reserved.

Runkel, A. C.; Tipping, R. G.; Alexander, Jr. , E. C.; Alexander, S. C.

2006-01-01

350

Hydrogeologic information in the Great Lakes basin, United States, and application of a geographic information system to public supply wells and hazardous-waste sites  

USGS Publications Warehouse

A computerized data base has been established to facilitate analysis and interpretation of potential for ground-water contamination in the Great Lakes basin. The computerized data base is being used in conjunction with a geogrpahic information system (GIS). Locations of public-supply wells were obtained from Federal and State agencies and stored in the system. Well locations are displayed using the Albers equal-area projection. A GIS was used to create a map of public-supply wells and a map of combined waste sites and public-supply wells. A comprehensive bibliography of 1,114 references, published during the period 1960-86, pertaining to hydrogeologic studies in the Great Lakes basin and geographic information systems, has been compiled using a relational data-base program. Where possible, references are indexed by State and county to assist in determining areas where additional study is necessary.

Warner, Kelly L.; Earle, John D.; Sherrill, Marvin G.

1991-01-01

351

Compilation of Water-Resources Data and Hydrogeologic Setting for the Allison Woods Research Station in Iredell County, North Carolina, 2005-2008  

USGS Publications Warehouse

Water-resources data were collected to describe the hydrologic conditions at the Allison Woods research station near Statesville, North Carolina, in the Piedmont Physiographic Province of North Carolina. Data collected by the U.S. Geological Survey and the North Carolina Department of Environment and Natural Resources, Division of Water Quality, from April 2005 through September 2008 are presented in this report. Data presented include well-construction characteristics and periodic groundwater-level measurements for 29 wells, borehole geophysical logs for 8 wells, hourly groundwater-level measurements for 5 wells, continuous water-quality measurements for 3 wells, periodic water-quality samples for 12 wells and 1 surface-water station, slug-test results for 11 wells, and shallow groundwater-flow maps. In addition, the geology and hydrogeology at the site are summarized.

Huffman, Brad A.; Abraham, Joju.

2010-01-01

352

Combined Estimation of Hydrogeologic Conceptual Model, Parameter, and Scenario Uncertainty with Application to Uranium Transport at the Hanford Site 300 Area  

SciTech Connect

This report to the Nuclear Regulatory Commission (NRC) describes the development and application of a methodology to systematically and quantitatively assess predictive uncertainty in groundwater flow and transport modeling that considers the combined impact of hydrogeologic uncertainties associated with the conceptual-mathematical basis of a model, model parameters, and the scenario to which the model is applied. The methodology is based on a n extension of a Maximum Likelihood implementation of Bayesian Model Averaging. Model uncertainty is represented by postulating a discrete set of alternative conceptual models for a site with associated prior model probabilities that reflect a belief about the relative plausibility of each model based on its apparent consistency with available knowledge and data. Posterior model probabilities are computed and parameter uncertainty is estimated by calibrating each model to observed system behavior; prior parameter estimates are optionally included. Scenario uncertainty is represented as a discrete set of alternative future conditions affecting boundary conditions, source/sink terms, or other aspects of the models, with associated prior scenario probabilities. A joint assessment of uncertainty results from combining model predictions computed under each scenario using as weight the posterior model and prior scenario probabilities. The uncertainty methodology was applied to modeling of groundwater flow and uranium transport at the Hanford Site 300 Area. Eight alternative models representing uncertainty in the hydrogeologic and geochemical properties as well as the temporal variability were considered. Two scenarios represent alternative future behavior of the Columbia River adjacent to the site were considered. The scenario alternatives were implemented in the models through the boundary conditions. Results demonstrate the feasibility of applying a comprehensive uncertainty assessment to large-scale, detailed groundwater flow and transport modeling and illustrate the benefits of the methodology I providing better estimates of predictive uncertiay8, quantitative results for use in assessing risk, and an improved understanding of the system behavior and the limitations of the models.

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

2007-07-30

353

The role of regional groundwater flow in the hydrogeology of the Culebra member of the Rustler formation at the Waste Isolation Pilot Plant (WIPP), southeastern New Mexico  

SciTech Connect

Numerical simulation has been used to enhance conceptual understanding, of the hydrogeology of the Culebra Dolomite in the context of regional groundwater flow. The hydrogeology is of interest because this unit is a possible pathway for offsite migration of radionuclides from a proposed repository for defense-generated transuranic wastes (the Waste Isolation Pilot Plant). The numerical model used is three-dimensional, extends laterally to topographic features that form the actual boundaries of a regional groundwater system, and uses a free-surface upper boundary condition to simulate the effect of change in the rate of recharge on groundwater flow. Steady-state simulations were performed to examine the sensitivity of simulation results to assumed values for hydraulic conductivity and recharge rate. Transient simulations, covering the time period from 14,000 years in the past to 10,000 years in the future, provided insight into how patterns of groundwater flow respond to changes in climate. Simulation results suggest that rates and directions of Groundwater flow in the Culebra change with time due to interaction between recharge, movement of the water table, and the topography of the land surface. The gentle east-to-west slope of the land surface in the vicinity of the WIPP caused groundwater in the Culebra to flow toward and discharge into Nash Draw, a topographic depression. Modern-day flow directions in the Culebra reflect regional rather than local features of the topography. Changes in Groundwater flow, however, lagged behind changes in the rate of recharge. The present-day position of the water table is still adjusting to the decrease in recharge that ended 8,000 years ago. Contaminants introduced into the Culebra will travel toward the accessible environment along the Culebra rather than by leaking upward or downward into other units. Natural changes in flow over the next 10,000 years will be small and will mainly reflect future short-term wet periods.

Corbet, T.F. [Sandia National Lab., Albuquerque, NM (United States)] [Sandia National Lab., Albuquerque, NM (United States); Knupp, P.M. [Ecodynamics Research Associates, Albuquerque, NM (United States)] [Ecodynamics Research Associates, Albuquerque, NM (United States)

1996-12-01

354

A Study of Hydrogeological Conditions of the Nubian Sandstone Aguifer in the Area between Abu Simbel and Toschka, Western Desert, Egypt.  

NASA Astrophysics Data System (ADS)

A Study of Hydrogeological Conditions of the Nubian Sandstone Aquifer in the Area between Abu Simbel and Toschka, Western Desert, Egypt. By K. A. Dahab*, A. M. Ebraheem**, and E. El Sayed*** *Geology Department, Faculty of Science, Menofia University, Shibin El Kom, Egypt. ** Geology Department, Faculty of Science, Assiut University, Assiut, Egypt. *** Geology Department, Faculty of Science, Minia University, Minia, Egypt. The Nubian Sandstone Aquifer in the area between Toschka and Abu Simbil is small portion of the very well known Nubian Sandstone Aquifer System in the Eastern Sahara, which covers the entire area of southwest Egypt, southeast Libya, northeast Chad, and northern Sudan. Toscha area is currently the site of intensive drilling and development for a huge land reclamation project. The drilling information was used to study the hydrogeological setting of the Nubian Sandstone aquifer in the area. The obtained results indicate that the lithological