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Sample records for hydrogeology

  1. Hydrogeology

    SciTech Connect

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

    1988-01-01

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

  2. Undergraduate Education in Hydrogeology.

    ERIC Educational Resources Information Center

    Tinker, John Richard, Jr.

    1989-01-01

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

  3. HYDROGEOLOGIC CASE STUDIES

    EPA Science Inventory

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

  4. Education and Employment in Hydrogeology.

    ERIC Educational Resources Information Center

    Pederson, Darryll T.

    1987-01-01

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

  5. HYDROGEOLOGIC CASE STUDIES (CHICAGO, IL)

    EPA Science Inventory

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

  6. HYDROGEOLOGIC CASE STUDIES (DENVER PRESENTATION)

    EPA Science Inventory

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

  7. Hydrogeologic Case Studies (Seattle, WA)

    EPA Science Inventory

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

  8. Hydrogeology of Government Marsh

    SciTech Connect

    Kasenow, M.C. . Dept. of Geography and Geology)

    1994-04-01

    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.

  9. Coral reef hydrogeology

    SciTech Connect

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

    1985-05-21

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

  10. Hydrogeologic characterization of Illinois wetlands

    SciTech Connect

    Miner, J.J.; Miller, M.V.; Rorick, N.L.; Fucciolo, C.S. )

    1994-04-01

    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.

  11. Using hydrogeology to site wetland compensation

    USGS Publications Warehouse

    Miller, Michael V.; Fucciolo, Christine S.; Miner, James J.

    1998-01-01

    The Illinois State Geological Survey has designed an initial site evaluation (ISE) procedure to rapidly separate candidate sites that have favorable hydrogeologic characteristics for wetland restoration or creation from sites where success is doubtful or difficult. ISE aims to focus compensation efforts on sites where former wetland hydrology can be restored or where the hydrogeology of wetlands in similar landscape positions can be reproduced.

  12. SRS Geology/Hydrogeology Environmental Information Document

    SciTech Connect

    Denham, M.E.

    1999-08-31

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

  13. Advanced Borehole Radar for Hydrogeology

    NASA Astrophysics Data System (ADS)

    Sato, M.

    2014-12-01

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

  14. Teaching hydrogeology: a review of current practice

    NASA Astrophysics Data System (ADS)

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

    2012-07-01

    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.

  15. The hydrogeology of Kilauea volcano

    SciTech Connect

    Ingebritsen, S.E.; Scholl, M.A. )

    1993-08-01

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

  16. The hydrogeology of Kilauea volcano

    USGS Publications Warehouse

    Ingebritsen, S.E.; Scholl, M.A.

    1993-01-01

    The hydrogeology of Kilauea volcano and adjacent areas has been studied since the turn of this century. However, most studies to date have focused on the relatively shallow, low-salinity parts of the ground-water system, and the deeper hydrothermal system remains poorly understood. The rift zones of adjacent Mauna Loa volcano bound the regional ground-water flow system that includes Kilauea, and the area bounded by the rift zones of Kilauea and the ocean may comprise a partly isolated subsystem. Rates of ground-water recharge vary greatly over the area and discharge is difficult to measure, because streams are ephemeral and most ground-water discharges diffusely at or below sea level. Hydrothermal systems exist at depth in Kilauea's cast and southwest rift zone, as evidenced by thermal springs at the coast and wells in the lower east-rift zone. Available data suggest that dike-impounded, heated ground water occurs at relatively high elevations in the upper east-and southwest-rift zones of Kilauea, and that permeability at depth in the rift zones (probably 10 10 m2). Substantial variations in permeability and the presence of magmatic heat sources influence the structure of the fresh water-salt water interface, so the Ghyben-Herzberg model will often fail to predict its position. Numerical modeling studies have considered only subsets of the hydrothermal system, because no existing computer code solves the coupled fluid-flow, heat- and solute-transport problem over the temperature and salinity range encountered at Kilauea. ?? 1993.

  17. SRP Baseline Hydrogeologic Investigation, Phase 3

    SciTech Connect

    Bledsoe, H.W.

    1988-08-01

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

  18. SRP baseline hydrogeologic investigation: Aquifer characterization

    SciTech Connect

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

    1992-03-31

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

  19. SRP baseline hydrogeologic investigation, Phase 2

    SciTech Connect

    Bledsoe, H.W.

    1987-11-01

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

  20. HydroCube: an entity-relationship hydrogeological data model

    NASA Astrophysics Data System (ADS)

    Wojda, Piotr; Brouyère, Serge; Derouane, Johan; Dassargues, Alain

    2010-12-01

    Managing, handling and accessing hydrogeological information depends heavily on the applied hydrogeological data models, which differ between institutions and countries. The effective dissemination of hydrogeological information requires the convergence of such models to make hydrogeological information accessible to multiple users such as universities, water suppliers, and administration and research organisations. Furthermore, because hydrogeological studies are complex, they require a wide variety of high-quality hydrogeological data with appropriate metadata in clearly designed and coherent structures. A need exists, therefore, to develop and implement hydrogeological data models that cover, as much as possible, the full hydrogeological domain. A new data model, called HydroCube, was developed for the Walloon Region in Belgium in 2005. The HydroCube model presents an innovative holistic project-based approach which covers a full set of hydrogeological concepts and features, allowing for effective hydrogeological project management. The model stores data relating to the project locality, hydrogeological equipment, and related observations and measurements. In particular, it focuses on specialized hydrogeological field experiments such as pumping and tracer tests. This logical data model uses entity-relationship diagrams and it has been implemented in the Microsoft Access environment. It has been enriched with a fully functional user interface.

  1. Small Scale Multisource Site – Hydrogeology Investigation

    EPA Science Inventory

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

  2. The ancient Chinese notes on hydrogeology

    NASA Astrophysics Data System (ADS)

    Zhou, Yu; Zwahlen, François; Wang, Yanxin

    2011-08-01

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

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

    SciTech Connect

    Link, P.K.

    1994-07-01

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

  4. Is Current Hydrogeologic Research Addressing Long-TermPredictions?

    SciTech Connect

    Tsang, Chin-Fu

    2004-09-10

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

  5. Hydrogeological aspects of agricultural drainage in Ireland

    NASA Astrophysics Data System (ADS)

    Burdon, David J.

    1986-02-01

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

  6. Hydrogeology of the Islamic Republic of Mauritania

    USGS Publications Warehouse

    Friedel, Michael J.; Finn, Carol

    2008-01-01

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

  7. Case studies in organic contaminant hydrogeology

    NASA Astrophysics Data System (ADS)

    Baker, John A.

    1989-07-01

    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.

  8. SRS baseline hydrogeologic investigation: Summary report

    SciTech Connect

    Bledsoe, H.W.; Aadland, R.K.; Sargent, K.A.

    1990-11-01

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

  9. Chemical hydrogeology in natural and contaminated environments

    USGS Publications Warehouse

    Back, W.; Baedecker, M.J.

    1989-01-01

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

  10. Hydrogeological Conditions Changes of Tomsk, Russia

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

  11. Hydrogeological Characterization in the Mizunami Underground Research Laboratory Project

    NASA Astrophysics Data System (ADS)

    Saegusa, H.; Takeuchi, R.; Ohyama, T.; Takeuchi, S.

    2008-12-01

    The Mizunami Underground Research Laboratory (MIU) is now under construction by Japan Atomic Energy Agency in the Cretaceous Toki granite in the Tono area of central Japan. One of the main goals of the MIU project, which is a broad scientific study of the deep geological environment as a basis of research and development for geological disposal of nuclear wastes, is to establish comprehensive techniques for the investigation, analysis and assessment of the deep geological environment in fractured crystalline rock. The conceptual design of the MIU consists of two 1,000 m shafts and horizontal research galleries. The project is implemented in three overlapping phases: Surface-based Investigation (Phase I), Construction (Phase II) and Operation (Phase III), with a total duration of 20 years. In Phase I, hydrogeological investigations have been carried out in a stepwise manner in order to obtain information on important parameters such as, water balance at the surface, location of water conducting features, hydraulic parameters, hydraulic connectivity and groundwater pressure distribution. Hydrogeological modeling and groundwater flow simulations, which are: 1) for evaluation of undisturbed hydrogeological and groundwater flow conditions before excavation of the URL and 2) for estimations of volume of inflow into the shafts and galleries and changes of water table and hydraulic pressure, 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. In Phase II, long-term hydraulic monitoring which is for mainly determination and assessment of hydraulic responses during excavation of the shafts and galleries, geological mapping and hydraulic testing using boreholes drilled from underground galleries have been also carried out. Based on the results of these investigations, hydrogeological model constructed in Phase I has been tested and revised. Lessons learned through the hydrogeological characterization are as follows; - Hydrogeological characterization combining field investigations and hydrogeological modeling iteratively is quite efficient. - Data of hydraulic transient change is useful to calibrate the hydrogeological model and to constrain the uncertainties of characteristics of groundwater flow. - It has possibility that the existence of unknown hydrogeological structures can be predicted by combining the hydraulic monitoring with calibration of hydrogeological models. The study to establish comprehensive techniques for investigation, analysis and assessment of hydrogeological environments will be continued in Phase II and Phase III of the MIU project.

  12. Marine hydrogeology: recent accomplishments and future opportunities

    NASA Astrophysics Data System (ADS)

    Fisher, A. T.

    2005-03-01

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

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

    SciTech Connect

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

    1995-09-01

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

  14. HYDROGEOLOGIC CASE STUDIE(PRESENTATION FOR MNA WORKSHOP)

    EPA Science Inventory

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

  15. Hydrogeology in North America: past and future

    NASA Astrophysics Data System (ADS)

    Narasimhan, T. N.

    2005-03-01

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

  16. Peatland hydrogeological function at the regional scale

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  17. Geology and hydrogeology of the Florida Keys

    USGS Publications Warehouse

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

    1997-01-01

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

  18. 2101-M Pond hydrogeologic characterization report

    SciTech Connect

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

    1990-09-01

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

  19. SRP baseline hydrogeologic investigation: Phase I

    SciTech Connect

    Bledsoe, H.W. Jr.

    1984-11-01

    The objective was to install 17 to 18 well clusters of approximately 8 wells each at key locations across the SRP site in order to: (1) provide information on the lithology, stratigraphy, and hydrogeology of the plant site; and (2) provide high quality observation wells to monitor the groundwater quality, hydraulic heat relationships, gradients, and flow paths that exist at present and to track how these parameters may change in the future as water use increases or decreases both on and off the plant site. The Phase I program consisted of geologic sampling, geophysical logging, physical testing of selected sediment samples, and construction of 20 observation wells located at three widely spaced cluster sites (P-13, P-14, and P-15). The target horizons for completion of wells at each cluster location included: (1) bottom of the lower Tuscaloosa aquifer; (2) top of the lower Tuscaloosa aquifer; (3) bottom of the upper Tuscaloosa aquifer; (4) top of the upper Tuscaloosa aquifer; (5) bottom of the Congaree aquifer; (6) top of the Congaree aquifer; (7) bottom of the McBean Formation; and (8) the water table. The actual completion depths of the wells vary depending on the ground surface elevation and the specific geologic conditions encountered at each cluster location. 10 refs., 18 figs.

  20. Hydrogeology of formation waters, northwestern Alberta basin

    SciTech Connect

    Bachu, S.; Underschultz, J.R. )

    1993-10-01

    Generally, temperature seems to be the main controlling factor on salinity distributions. The salinity of formation waters increases in the vicinity of evaporitic beds, and decreases close to the surface because of mixing with fresh meteoric water introduced through local flow systems. The Lower and Middle Devonian pre-Prairie aquifer systems, beneath the regionally extensive Prairie aquiclude, are characterized by regional topographically-driven flow updip to the northeast. The flow of formation waters in the northeastern Alberta played an important role in the formation of the huge Athabasca oil sands deposits. Hydrocarbons that migrated into the area from the west were trapped into local reservoirs, and biodegraded and washed by fresh meteoric water introduced by local flow systems. Environmentally, the subsurface hydrogeology in the area imposes specific constraints on waste disposal in deep formations mostly because of the absence of a thick, continuous regional aquitard and because most aquifers subcrop at shallow depth or crop out and discharge along the valleys of the Athabasca River system and at the basin edge.

  1. Hydrogeologic investigations at the Nevada Test Site

    SciTech Connect

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

    1992-01-01

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

  2. Coupled Hydrogeophysical Inversion and Hydrogeological Data Fusion

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  3. Airborne EM for geothermal and hydrogeological mapping

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  4. Flowing with the changing needs of hydrogeology instruction

    NASA Astrophysics Data System (ADS)

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

    2012-01-01

    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.

  5. Python-Based Applications for Hydrogeological Modeling

    NASA Astrophysics Data System (ADS)

    Khambhammettu, P.

    2013-12-01

    Python is a general-purpose, high-level programming language whose design philosophy emphasizes code readability. Add-on packages supporting fast array computation (numpy), plotting (matplotlib), scientific /mathematical Functions (scipy), have resulted in a powerful ecosystem for scientists interested in exploratory data analysis, high-performance computing and data visualization. Three examples are provided to demonstrate the applicability of the Python environment in hydrogeological applications. Python programs were used to model an aquifer test and estimate aquifer parameters at a Superfund site. The aquifer test conducted at a Groundwater Circulation Well was modeled with the Python/FORTRAN-based TTIM Analytic Element Code. The aquifer parameters were estimated with PEST such that a good match was produced between the simulated and observed drawdowns. Python scripts were written to interface with PEST and visualize the results. A convolution-based approach was used to estimate source concentration histories based on observed concentrations at receptor locations. Unit Response Functions (URFs) that relate the receptor concentrations to a unit release at the source were derived with the ATRANS code. The impact of any releases at the source could then be estimated by convolving the source release history with the URFs. Python scripts were written to compute and visualize receptor concentrations for user-specified source histories. The framework provided a simple and elegant way to test various hypotheses about the site. A Python/FORTRAN-based program TYPECURVEGRID-Py was developed to compute and visualize groundwater elevations and drawdown through time in response to a regional uniform hydraulic gradient and the influence of pumping wells using either the Theis solution for a fully-confined aquifer or the Hantush-Jacob solution for a leaky confined aquifer. The program supports an arbitrary number of wells that can operate according to arbitrary schedules. The python wrapper invokes the underlying FORTRAN layer to compute transient groundwater elevations and processes this information to create time-series and 2D plots.

  6. Hydrogeology of Ljubljana polje perched aquifers

    NASA Astrophysics Data System (ADS)

    Šram, D.; Brenčič, M.

    2012-04-01

    Ljubljana polje aquifer lies in central part of Slovenia and is one of the biggest and most important aquifers in Slovenia. Aquifer was formed in quaternary basin which was filled with sediments from local rivers. River Sava is the biggest and the most important among them. Thickness of the aquifer varies from 20 m to 100 m. In general it is an unconfined aquifer, but locally, between gravel and sand sediments which have good hydraulic conductivity, layers with low hydraulic conductivity, such as silt and clay, appear. Those layers or lenses can form perched aquifers. Perched aquifers are important for prevention of pollution of the main aquifer and also for the water recharge in the time periods with high precipitation. The perched aquifers were located by boreholes, while their spatial distribution has not been studied yet. Within the project INCOME all the existing lithological borehole logs were collected and analysed with Jewel Suite 2011 software. A geostatistical method sequential indicator simulation was used to create spatial distribution of five hydrofacies at the Ljubljana polje aquifer. The layers/lenses that are bigger than 0.07 km2 and have hydraulic conductivity lower than K = 10-7 m/s were defined as lenses that can potentially form perched aquifers. In the modelling area, two areas with higher concentration of lenses with low hydraulic conductivity were defined. At those areas, according to the borehole data, perched aquifers appear few meters below surface to the depth around 30 m. At the other parts of the model area lenses with low hydraulic conductivity are less abundant. With spatial information (lateral and vertical extension) of perched aquifers in Ljubljana polje improvement of existing hydrogeological models can be made which can help to improve the qualitative and quantitative status of the Ljubljana polje main aquifer.

  7. Hydrogeologic atlas of aquifers in Indiana

    USGS Publications Warehouse

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

    1994-01-01

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

  8. 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...

  9. 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...

  10. The French network of hydrogeological sites H+

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

    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.

  11. Hydrogeology of the Azores volcanic archipelago (Portugal)

    NASA Astrophysics Data System (ADS)

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

    2009-04-01

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

  12. Groundwater availability as constrained by hydrogeology and environmental flows

    USGS Publications Warehouse

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

    2014-01-01

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

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

    PubMed

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

    2014-01-01

    Groundwater pumping from aquifers in hydraulic connection with nearby streams has the potential to cause adverse impacts by decreasing flows to levels below those necessary to maintain aquatic ecosystems. The recent passage of the Great Lakes-St. Lawrence River Basin Water Resources Compact has brought attention to this issue in the Great Lakes region. In particular, the legislation requires the Great Lakes states to enact measures for limiting water withdrawals that can cause adverse ecosystem impacts. This study explores how both hydrogeologic and environmental flow limitations may constrain groundwater availability in the Great Lakes Basin. A methodology for calculating maximum allowable pumping rates is presented. Groundwater availability across the basin may be constrained by a combination of hydrogeologic yield and environmental flow limitations varying over both local and regional scales. The results are sensitive to factors such as pumping time, regional and local hydrogeology, streambed conductance, and streamflow depletion limits. Understanding how these restrictions constrain groundwater usage and which hydrogeologic characteristics and spatial variables have the most influence on potential streamflow depletions has important water resources policy and management implications. PMID:23582026

  14. An integrated theoretical and practical approach for teaching hydrogeology

    NASA Astrophysics Data System (ADS)

    Bonomi, Tullia; Fumagalli, Letizia; Cavallin, Angelo

    2013-04-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  16. Hydrogeologic framework and estimates of ground-water volumes in Tertiary and upper Cretaceous hydrogeologic units in the Powder River basin, Wyoming

    USGS Publications Warehouse

    Hinaman, Kurt

    2005-01-01

    The Powder River Basin in Wyoming and Montana is an important source of energy resources for the United States. Coalbed methane gas is contained in Tertiary and upper Cretaceous hydrogeologic units in the Powder River Basin. This gas is released when water pressure in coalbeds is lowered, usually by pumping ground water. Issues related to disposal and uses of by-product water from coalbed methane production have developed, in part, due to uncertainties in hydrologic properties. One hydrologic property of primary interest is the amount of water contained in Tertiary and upper Cretaceous hydrogeologic units in the Powder River Basin. The U.S. Geological Survey, in cooperation with the Bureau of Land Management, conducted a study to describe the hydrogeologic framework and to estimate ground-water volumes in different facies of Tertiary and upper Cretaceous hydrogeologic units in the Powder River Basin in Wyoming. A geographic information system was used to compile and utilize hydrogeologic maps, to describe the hydrogeologic framework, and to estimate the volume of ground water in Tertiary and upper Cretaceous hydrogeologic units in the Powder River structural basin in Wyoming. Maps of the altitudes of potentiometric surfaces, altitudes of the tops and bottoms of hydrogeologic units, thicknesses of hydrogeologic units, percent sand of hydrogeologic units, and outcrop boundaries for the following hydrogeologic units were used: Tongue River-Wasatch aquifer, Lebo confining unit, Tullock aquifer, Upper Hell Creek confining unit, and the Fox Hills-Lower Hell Creek aquifer. Literature porosity values of 30 percent for sand and 35 percent for non-sand facies were used to calculate the volume of total ground water in each hydrogeologic unit. Literature specific yield values of 26 percent for sand and 10 percent for non-sand facies, and literature specific storage values of 0.0001 ft-1 (1/foot) for sand facies and 0.00001 ft-1 for non-sand facies, were used to calculate a second volume of ground water for each hydrogeologic unit. Significant figure considerations limited estimates of ground-water volumes to two significant digits. A total ground-water volume of 2.0x1014 ft3 (cubic feet) was calculated using porosity values, and a total ground-water volume of 3.6x1013 ft3 was calculated using specific yield and specific storage values. These results are consistent with retention properties, which would have some of the total water being retained in the sediments. Sensitivity analysis shows that the estimates of ground-water volume are most sensitive to porosity. The estimates also are sensitive to confined thickness and saturated thickness. Better spatial information for hydrogeologic units could help refine the ground-water volume estimates.

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

    SciTech Connect

    Bechtel Nevada and National Security Technologies, LLC

    2006-09-01

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

  18. The hydrogeologic-geochemical model of Cerro Prieto revisited

    SciTech Connect

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

    1989-01-01

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

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

    USGS Publications Warehouse

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

    1983-01-01

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

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

    USGS Publications Warehouse

    Fine, Jason M.

    2008-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

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

    USGS Publications Warehouse

    Flint, L.E.

    1998-01-01

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

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

    SciTech Connect

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

    1989-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  5. Impacts of rainfall spatial variability on hydrogeological response

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

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

    USGS Publications Warehouse

    Apple, Beth A.; Reeves, Howard W.

    2007-01-01

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

  8. Warning system for hydrogeological hazards in Campania (Southern Italy)

    NASA Astrophysics Data System (ADS)

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

    2010-05-01

    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.

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

    SciTech Connect

    Flint, L.E.

    1998-09-01

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

  10. Hydrogeologic Assessment of the Pixley National WildlifeRefuge

    SciTech Connect

    Quinn, Nigel W.T.

    2007-10-01

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

  11. Fault Hydrogeology Characterization for a Civil Infrastructure Project

    NASA Astrophysics Data System (ADS)

    Sholley, M. G.; Waterman, M. K.; Attanayake, P. M.

    2011-12-01

    Planning for the construction of an 18-ft diameter water conveyance tunnel in Southern California was made additionally complex due to the tunnel alignment crossing the San Andreas Fault and a tunnel portal within an area of elevated groundwater temperatures associated with branches/splays of the Arrowhead Spring fault system. This abstract describes the investigation techniques used to characterize the hydrogeology associated with these faults and the conceptual models developed to assist with hazard mitigation during construction. From an early phase of the project it was recognized that tunneling through the San Andreas Fault posed the risk of increased groundwater inflows and therefore potentially hazardous construction conditions. Characterization of the fault focused on estimating those parameters critical to the groundwater regime. In addition to geologic mapping, several boreholes were drilled and the cores logged to determine rock mass characteristics. Prior to installing monitoring wells in these boreholes, in-situ testing to determine hydraulic conductivity was conducted with a double packer system. Analysis of the packer test results demonstrated that factors found to have significant correspondence to hydraulic conductivity were depth of test and proximity to faults. The combination of rock mass characterization, hydraulic conductivity distribution, and water levels were then used to estimate groundwater inflows to the tunnel. The inflow estimates were developed to provide a measure for determining the need to prevent and control the inflows and in identifying likely delays in construction progress. Two semi-empirical methods were used to evaluate the probable magnitude of tunnel inflow. This combination of field techniques and analyses led to a preliminary understanding of the hydrogeological characteristics of the San Andreas Fault and the potential interaction between tunnel construction and the groundwater resource. A detailed understanding of the hydrogeology associated with the Arrowhead Spring fault system was required because elevated groundwater temperatures and adverse chemistry posed a risk for tunneling. Standard investigation techniques were employed including borings, geologic mapping with trenching, resistivity surveys, installation and monitoring of observation wells, and assessment of surface water features in the area. A detailed geological model was constructed based on the drilling, mapping and resistivity surveys, but due to the fractured nature of the rock, water level measurements provided little insight into the groundwater flow regime. Under these circumstances, the hydrochemistry proved to be significant. Through the use of the expanded Durov plot, the major ion chemistry contributed to characterization of different water types, their origin, the delineation of the geothermal regime, and the influence of the fault on the groundwater regime. The combination of geological and hydrochemical characterization led to an understanding of the hydrogeology associated with the Arrowhead Springs Fault, and potential impacts to construction as a result of the characterization.

  12. The influence of hydrogeology on site effects at strong earthquakes

    NASA Astrophysics Data System (ADS)

    Hötzl, H.; Hannich, D.; Bretotean, M.; Danchiv, D.; Zamfirescu, F.; Ciugudean, V.

    2003-04-01

    The explanation of most variable site effects at a given place, in correlation with seismic events at relative equal and constant hypocentral and epicentral distances, must depend preferentially on the local geologic conditions of the shallow underground. The contribution of the hydrogeologic conditions to observed site effects is studied in the frame of a German/Romanian cooperative project in correlation with Vrancea earthquakes. In the case of the capital of Romania, Bucharest, the specific properties of Vrancea seismicity, with strong earthquakes at intermediate depths and relative constant distances of about 150 km to Bucharest, the source directivity and ground motion attenuation cannot vary on the scale of the city size. Therefore exclusively site effects must cause the variation in ground motion in the city. The complex geologic and hydrogeologic conditions of the shallow underground of Bucharest, with soft soil layers and three main aquifer systems in the relative thick Quaternary deposits (100-300 m) oblige to take the hydrogeology also in account for explaining the diversified site effects. As a new kind of handling of this problem, the complexity of hydrogeologic conditions in Bucharest is studied under different aspects: An integrative analysis of various properties and parameters of the aquifers, systematised under GIS, is elaborated. Groundwater level variations and their direct influence on the liquefaction potential of shallow sandy layers are studied. Long-term variations of groundwater level in representative piezometer boreholes in Bucharest are evaluated and interpreted in connection with observed site effects. Experimental observations of pore-water pressure increasing triggered by earthquakes are executed, to study in-situ the liquefaction conditions. The variation of the shear wave velocity of sandy layers in dry and water-saturated state is studied, to establish the influence of them on response spectra. A 2D-groundwater model for the upper most aquifer, the Colentina-aquifer, is elaborated to permit to estimate for a given period in advance the probably groundwater level and correlated with this, the seismic risk due to the increased liquefaction potential and the shear wave velocity variation.

  13. Proceedings of the joint Russian-American hydrogeology seminar

    SciTech Connect

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

    1997-12-31

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

  14. Hydrogeology of the Sarasota-Port Charlotte area, Florida

    USGS Publications Warehouse

    Wolansky, R.M.

    1983-01-01

    The surficial and intermediate aquifers are the major source of public water supplies in the Sarasota-Port Charlotte, Florida, area because of the relatively poor quality of Floridan aquifer water. The hydrogeologic framework consists of the surficial aquifer, intermediate aquifers (Tamiami-upper Hawthorn and lower Hawthorn-upper Tampa aquifers) and confining beds, Floridan aquifer, and lower confining bed (or base of the Floridan aquifer). The quality of ground water in the surficial and intermediate aquifers is generally good, except in the western (coastal) and southern parts where saltwater intrusion or incomplete flushing of connate water has occurred. The mineral content of ground water generally increases with depth and areally from the northeast towards the west and south. A water budget for the study area shows that an average annual rainfall of 51.0 inches minus an evapotranspiration of 38.0 inches per year and streamflow of 12.5 inches per year leaves 0.5 inch per year of recharge to the surficial aquifer. Combined pumpage from the aquifers is 1.06 inches per year. A preliminary quasi-time dimensional model has been applied to the study area to check the reasonableness of the hydrogeologic framework defined and of aquifer parameters. The model was considered calibrated when the final head matrix was within plus or minus 5 feet of the starting head. (USGS)

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

    NASA Astrophysics Data System (ADS)

    Humphreys, W. F.

    2009-02-01

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

  16. The application of seismic techniques to hydrogeological investigations

    NASA Astrophysics Data System (ADS)

    Jarvis, Kevin Donald Gibson

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

  17. Evolution of the notion of time in hydrogeology

    NASA Astrophysics Data System (ADS)

    Narasimhan, T. N.

    1986-10-01

    The AGU Hydrology Section sponsored a special session on History and Heritage of Hydrology between 8:30 A.M. and 12 noon on Monday, December 9, 1985, during the Fall Meeting at San Francisco. The session was chaired by T. N. Narasimhan of Lawrence Berkeley Laboratory (Berkeley, Calif.). The attendance of between 100 and 120 for each talk was indicative of a healthy interest among researchers on matters related to history.The first part of the session focused attention on the theme “The Evolution of the Notion of Time in Hydrogeology.” The last two speakers addressed topics outside of this theme. Simon Ince (University of Arizona, Tucson) presented a historical account of the contributions of 19th century French scientist Barre de Saint-Venant to transient flow of water in open channels. Olaf H. Pfannkuch (University of Minnesota, Minneapolis) presented a historical account of the Cult of Saint Barbara and the mining profession of medieval Europe. The following summary is restricted to an overview of those presentations that dealt with the evolution of the notion of time in hydrogeology.

  18. Mapping pollution and coastal hydrogeology with helicopterborne transient electromagnetic measurements

    NASA Astrophysics Data System (ADS)

    Christensen, Niels B.; Halkjær, Max

    2014-03-01

    Coastal hydrology is becoming the focus of increasing interest for several reasons. Hydrogeological models need good boundary conditions at the coastline, and with the expected sea level rise due to climate changes, it becomes increasingly important to grasp the dynamics of coastal hydrology in order to predict the consequences of sea level rise for nature and society. We present a helicopterborne transient electromagnetic survey from a region at the North Sea coast in western Jutland, Denmark, carried out at a seriously polluted site with the dual purpose of assessing the extent of the pollution and mapping the coastal hydrogeology to provide data for remediation activities. Data are subjected to constrained inversion with one-dimensional multi-layer (smooth) models. The extent of the pollution plume estimated from a conductive anomaly in the survey results is mainly in accordance with results from other investigations, but also points to hitherto unknown directions of seepage. The interleaving of freshwater extending under the offshore shallow sea and saltwater infiltrating under the onshore freshwater aquifer can be clearly discerned and preferential flow channels are revealed.

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

    USGS Publications Warehouse

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

    2010-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

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

    USGS Publications Warehouse

    Adamski, James C.; German, Edward R.

    2004-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

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

  3. Hydrogeologic Unit Flow Characterization Using Transition Probability Geostatistics

    SciTech Connect

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

    2003-11-21

    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.

  4. Convective Non-laminar and Turbulent Flow in Hydrogeologic Systems

    NASA Astrophysics Data System (ADS)

    Dwivedi, R.; Wilson, J. L.

    2008-12-01

    Convective flows due to heat transfer play an important role in many hydrogeologic systems. The generic systems considered here represent aquifers, subduction zones, and water or air-filled natural/man-made caves or mines. The fluid flow in these systems is often dominated by geothermal forcing, resulting in convection. The convection can be non-laminar or even turbulent, especially in cavities. In order to gain insight into these non-laminar and turbulent convective processes, a computational fluid dynamics (CFD) mathematical modeling approach is taken. For the purpose of comparison, and to better understand the change in the nature of each system, two other flow regimes, namely no-flow and laminar flows, are also considered. Patterns of convection, flow rates and residence times, and heat transfer rates are used to characterize and compare the different systems.

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

    USGS Publications Warehouse

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

    1995-01-01

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

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

    PubMed

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

    2012-11-01

    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

  7. Hydrogeologic correlations for selected wells on Long Island, New York; a data base with retrieval program

    USGS Publications Warehouse

    Buxton, H.T.; Shernoff, P.K.; Smolensky, D.A.

    1989-01-01

    Accurate delineation of the internal hydrogeologic structure of Long Island, NY is integral to the understanding and management of the groundwater system. This report presents a computerized data base of hydrogeologic correlations for 3,146 wells on Long Island and adjacent parts of New York City. The data base includes the well identification number, the latitude-longitude of the well location, the altitude of land surface at the well and of the bottom of the drilled hole, and the altitude of the top of the major hydrogeologic units penetrated by the well. A computer program is included that allows retrieval of selected types of data for all of, or any local area of, Long Island. These data retrievals are a valuable aid to the construction of hydrogeologic surface maps. (USGS)

  8. Hydrogeologic Data Fusion. Industry Programs/Characterization, Monitoring, and Sensor Technology Crosscut Program. OST Reference #2944

    SciTech Connect

    None, None

    1999-09-01

    Problem: The fate and transport of contaminants in the subsurface requires knowledge of the hydrogeologic system. Site characterization typically involves the collection of various data sets needed to create a conceptual model that represents what’s known about contaminant migration in the subsurface at a particular site. How Hydrogeologic Data Fusion Works Hydrogeologic Data Fusion is a mathematical tool that can be used to combine various types of geophysical, geologic, and hydrologic data from different types of sensors to estimate geologic and hydrogeologic properties. It can be especially useful at hazardous waste sites where the hydrology, geology, or contaminant distribution is significantly complex such that groundwater modeling is required to enable a reasonable and accurate prediction of subsurface conditions.

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

    USGS Publications Warehouse

    Welch, Wendy B.; Savoca, Mark E.

    2011-01-01

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

  10. GIS-based hydrogeological databases and groundwater modelling

    NASA Astrophysics Data System (ADS)

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

    2001-12-01

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

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

    SciTech Connect

    Foley, M.G.

    1994-05-01

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

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

    USGS Publications Warehouse

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

    1997-01-01

    In support of Yucca Mountain site characterization studies, a hydrogeologic framework was developed, and a hydrogeologic map was constructed for the Death Valley region. The region, covering approximately 100,000 km 2 along the Nevada-California border near Las Vegas, is characterized by isolated mountain ranges juxtaposed against broad, alluvium-filled valleys. Geologic conditions are typical of the Basin and Range Province; a variety of sedimentary and igneous intrusive and extrusive rocks have been subjected to both compressional and extensional deformation. The regional ground-water flow system can best be described as a series of connected intermontane basins in which ground-water flow occurs in basin-fill deposits, carbonate rocks, clastic rocks, and volcanic rocks. Previous investigations have developed more site-specific hydrogeologic relationships; however, few have described all the lithologies within the Death Valley regional ground-water flow system. Information required to characterize the hydrogeologic units in the region was obtained from regional geologic maps and reports. Map data were digitized from regional geologic maps and combined into a composite map using a geographic information system. This map was simplified to show 10 laterally extensive hydrogeologic units with distinct hydrologic properties. The hydraulic conductivity values for the hydrogeologic units range over 15 orders of magnitude due to the variability in burial depth and degree of fracturing.

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

    SciTech Connect

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

    1997-12-31

    In support of Yucca Mountain site characterization studies, a hydrogeologic framework was developed, and a hydrogeologic map was constructed for the Death Valley region. The region, covering approximately 100,000 km{sup 2} along the Nevada-California border near Las Vegas, is characterized by isolated mountain ranges juxtaposed against broad, alluvium-filled valleys. Geologic conditions are typical of the Basin and Range Province; a variety of sedimentary and igneous intrusive and extrusive rocks have been subjected to both compressional and extensional deformation. The regional ground-water flow system can best be described as a series of connected intermontane basins in which ground-water flow occurs in basin-fill deposits, carbonate rocks, clastic rocks, and volcanic rocks. Previous investigations have developed more site-specific hydrogeologic relationships; however, few have described all the lithologies within the Death Valley regional ground-water flow system. Information required to characterize the hydrogeologic units in the region was obtained from regional geologic maps and reports. Map data were digitized from regional geologic maps and combined into a composite map using a geographic information system. This map was simplified to show 10 laterally extensive hydrogeologic units with distinct hydrologic properties. The hydraulic conductivity values for the hydrogeologic units range over 15 orders of magnitude due to the variability in burial depth and degree of fracturing.

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

    SciTech Connect

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

    1993-10-01

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

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

    USGS Publications Warehouse

    Lacombe, Pierre J.; Burton, William C.

    2010-01-01

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

  16. A New Hydrogeological Research Site in the Willamette River Floodplain

    NASA Astrophysics Data System (ADS)

    Faulkner, B. R.; Cline, S. P.; Landers, D. H.; Forshay, K. J.

    2008-12-01

    The Willamette River is a ninth-order tributary of the Columbia which passes through a productive and populous region in northwest Oregon. Where unconstrained by shoreline revetments, the floodplain of this river is a high-energy, dynamic system which supports a variety of riparian forests and floodplain habitats. On the Green Island Restoration Site, north of the city of Eugene, several geomorphological features common to much of the Willamette floodplain are present. These features, ranging from young bare gravel bars, islands supporting mature forest stands, to agricultural areas bounded by levees. As part of a Memorandum of Understanding with the McKenzie River Trust, USEPA has constructed a network of fifty shallow monitoring wells on the Green Island site. Among the purposes are to characterize the hydrogeology of the multiple- island floodplain, the extent of hyporheic flow, and the temperature regime. The monitoring wells are located in areas ranging from a few meters from the river edge to several hundred meters away, within the agricultural areas. By automatic data-logging, flow nets will be developed using numerical modeling. Water quality data will be collected to measure the degee to which subsurface biogeochemistry is influenced by geomorphologic features that are determined by the processes of river channel migration, island formation, and colonization by riparian forest. The monitoring network will also be used to measure the groundwater quality effects of restoration projects currently underway. These include reforestation of previously agricultural areas, and levee removal.

  17. Hydrogeology of the Lake Tahoe Basin, California and Nevada

    USGS Publications Warehouse

    Plume, Russell W.; Tumbusch, Mary L.; Welborn, Toby L.

    2009-01-01

    Ground water in the Lake Tahoe basin is the primary source of domestic and municipal water supply and an important source of inflow to Lake Tahoe. Over the past 30-40 years, Federal, State, and local agencies, and research institutions have collected hydrologic data to quantify the ground-water resources in the Lake Tahoe basin. These data are dispersed among the various agencies and institutions that collected the data and generally are not available in a format suitable for basin-wide assessments. To successfully and efficiently manage the ground-water resources throughout the Lake Tahoe basin, the U.S. Geological Survey (USGS) in cooperation with the U.S. Forest Service (USFS) compiled and evaluated the pertinent geologic, geophysical, and hydrologic data, and built a geodatabase incorporating the consolidated and standardized data for the Lake Tahoe basin that is relevant for examining the extent and characteristics of the hydrogeologic units that comprise the aquifers. The geodatabase can be accessed at http://water.usgs.gov/lookup/getspatial?SIM3063.

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

    SciTech Connect

    Nativ, R.; Hunley, A.E.

    1993-07-01

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

  19. A New Assessment Framework for Transience in Hydrogeological Systems.

    PubMed

    Currell, Matthew; Gleeson, Tom; Dahlhaus, Peter

    2016-01-01

    The importance of transience in the management of hydrogeologic systems is often uncertain. We propose a clear framework for determining the likely importance of transient behavior in groundwater systems in a management context. The framework incorporates information about aquifer hydraulics, hydrological drivers, and time scale of management. It is widely recognized that aquifers respond on different timescales to hydrological change and that hydrological drivers themselves, such as climate, are not stationary in time. We propose that in order to assess whether transient behavior is likely to be of practical importance, three factors need to be examined simultaneously: (1) aquifer response time, which can be expressed in terms of the response to a step hydrological change (?step ) or periodic change (?cycle ); (2) temporal variation of the dominant hydrological drivers, such as dominant climatic systems in a region; (3) the management timescale and spatial scale of interest. Graphical tools have been developed to examine these factors in conjunction, and assess how important transient behavior is likely to be in response to particular hydrological drivers, and thus which drivers are most likely to induce transience in a specified management timeframe. The method is demonstrated using two case studies; a local system that responds rapidly and is managed on yearly to decadal timeframes and a regional system that exhibits highly delayed responses and was until recently being assessed as a high level nuclear waste repository site. Any practical groundwater resource problem can easily be examined using the proposed framework. PMID:25495337

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

    SciTech Connect

    Rubin, Yoram

    2001-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Petrucci, Olga; Aceto, Luigi

    2014-05-01

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

  2. Hydrogeologic effects of natural disruptive events on nuclear waste repositories

    SciTech Connect

    Davis, S.N.

    1980-06-01

    Some possible hydrogeologic effects of disruptive events that may affect repositories for nuclear wastte are described. A very large number of combinations of natural events can be imagined, but only those events which are judged to be most probable are covered. Waste-induced effects are not considered. The disruptive events discussed above are placed into four geologic settings. Although the geology is not specific to given repository sites that have been considered by other agencies, the geology has been generalized from actual field data and is, therefore, considered to be physically reasonable. The geologic settings considered are: (1) interior salt domes of the Gulf Coast, (2) bedded salt of southeastern New Mexico, (3) argillaceous rocks of southern Nevanda, and (4) granitic stocks of the Basin and Range Province. Log-normal distributions of permeabilities of rock units are given for each region. Chapters are devoted to: poresity and permeability of natural materials, regional flow patterns, disruptive events (faulting, dissolution of rock forming minerals, fracturing from various causes, rapid changes of hydraulic regimen); possible hydrologic effects of disruptive events; and hydraulic fracturing.

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

    SciTech Connect

    Cohen, A.J.B.

    1993-10-01

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

  4. Hydrogeologic reconnaissance of the San Miguel River basin, southwestern Colorado

    SciTech Connect

    Ackerman, D.J.; Rush, F.E.

    1984-01-01

    The San Miguel River basin is an area of 4130 square kilometers, of which about two-thirds is in the southeastern part of the Paradox basin. The Paradox basin is a part of the Colorado Plateaus that is underlain by a thick sequence of evaporite beds of Pennsylvanian age. The rock units that underlie the area have been grouped into hydrogeologic units based on their water-transmitting ability. Evaporite beds consisting mostly of salt are both overlain and underlain by confining beds. Aquifers are present above and below the confining-bed sequence. The principal element of ground-water outflow from the upper aquifer is flow to the San Miguel River and its tributaries; this averages about 90 million cubic meters per year. The aquifers generally are isolated from the evaporite beds by the bounding confining beds; as a result, most ground water has little, if any, contact with the evaporites. No natural brine flows have been identified in the basin. Salt water has been reported in petroleum-exploration wells, but no active salt solution has been located. 23 references, 8 figures, 4 tables.

  5. Conceptual Hydrogeologic Models for the Eastern Snake River Plain, Idaho

    NASA Astrophysics Data System (ADS)

    Johnson, E. G.; McLing, T. L.; Holt, R. M.

    2001-12-01

    We develop two alternative conceptual hydrogeologic models of the Eastern Snake River Plain (ESRP) aquifer to explain the spatial distribution of strontium and uranium isotope data. The ESRP aquifer flows southwesterly within a northeastern trending structural basin 200 miles long and 50 to 70 miles wide. The basin is composed of 3000 to 10000 feet of Late Cenozoic basalt, eolian sand and loess, and alluvial and lacustrine sediments. Up to 85 percent of the deposit is basalt from hundreds of flows where individual flow areas range from 2 to 900 square miles. The bulk of the recharge for the basin is derived from the Yellowstone Plateau, but other recharge waters with high (>.71100) 87Sr/86Sr ratios enter the basin from a series of alluvial valleys north of the ESRP. The first conceptual model includes regional-scale preferential flowpaths to explain the 87Sr/86Sr distribution, whereas groundwater mixing is the primary process in the second. Common factors in the conceptual model such as faulting, discontinuity of basalt flows, rift zones and sedimentary interbeds in the basin strongly affect groundwater flow. Additionally, a high geothermal gradient in the basin with associated upwelling waters may also influence the distribution of isotope ratios. Other factors also include local sediment sources for high 87Sr/86Sr ratios in the basin itself in addition to that entering form the valleys north of the plain. Estimates of critical time and length scales for each hydrologic process are compared.

  6. Hydrogeologic insights for a Devil's Slide-like system

    NASA Astrophysics Data System (ADS)

    Thomas, Matthew A.; Loague, Keith

    2014-08-01

    Tectonically active coastal margins commonly host landslides that are influenced by hydrologic, geologic, and/or anthropogenic perturbations. The work reported here is motivated by the hydrologically driven, deep-seated bedrock slides that intersect the (former) Pacific Coast Highway in the active landslide zone at Devil's Slide near Pacifica, California. Numerical simulation of subsurface flow is employed to investigate saturated zone fluid pressure scenarios for 3-D Devil's Slide-like systems. The four-phase concept-development effort is comprised of 134 hydrogeologic simulation scenarios which investigate fluid pressure response for complex subsurface conditions and historically based climate forcings. Recharge, heterogeneity, and anisotropy are shown to increase fluid pressures in targeted failure-prone locations by up to 73.8, 10.3, and 1.8 %, respectively. The interaction between fault zone characteristics and topographically driven flow are shown to influence fluid pressures for up to 85% of the approximately 7.0 × 105 m2 study area. Simulated fluid pressures support the known slope instability for the Devil's Slide site. A quantitative hypothesis-testing discussion explores the likelihood of perched water above the regional water table at the site. Further understanding of hydrologically driven slope movement in the active landslide zone will require additional data focused on rigorous characterization of the unsaturated zone.

  7. Hydrogeology in The Semi-Arid South-West of Madagascar - a Multi-Scale Approach

    NASA Astrophysics Data System (ADS)

    Englert, A.; Dworak, L.; Rasoloariniaina, J.; Brinkmann, K.; Kobbe, S.; Buerkert, A.

    2014-12-01

    The project „Sustainable Land Management" (SuLaMa) aims at the participatory development and implementation of alternative land-use management practices to protect the ecosystem and its biodiversity and improve the livelihood of the local population in a sustainable manner. One critical aspect within this project is the availability of sustainable water resources. To approach reliable estimates about the availability and dynamics of the water resources, we started a study to understand in detail the hydrogeology of the South-West of Madagascar. As this area has an extend of about 40000 square kilometers, the study is based on a multi-scale approach. Rough large scale estimates are utilized to develop a general understanding of the hydrogeology in the South-West of Madagascar, which allows for large scale estimates of hydrogeology under changing boundary conditions like climate change. Detailed investigations at target villages of the SuLaMa project, combined with boundary conditions derived from the large scale hydrogeological model, allows for estimates of the local hydrogeology under changing boundary conditions like enhanced water abstraction. Although several governmental and nongovernmental institutions have been working on the water resources of the South-West of Madagascar in the past, only few sources on the hydrogeology of this area can be found in literature. To improve the data base we installed five automatic loggers in the area to measure groundwater levels as function of time and investigated in detail about one hundred wells in terms of geometry, groundwater level, electrical conductivity and pH. First preliminary results of the study show that the hydrogeology in the study area is dominated by four major hydrogeological units (fractured crystalline basement, karstic plateau, porous perched aquifers and a porous coastal area) and can be analyzed effectively by assuming a radial symmetric geometry. Ongoing efforts are the development of a model for a spatially variable groundwater recharge estimates and advanced hydrogeological models. The latter consisting of high resolution small scale and low resolution large scale estimates. Based on these models, we will develop numerical flow models to evaluate water resources as function of changing boundary conditions at multiple scales.

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

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

  9. Groundwater quality in the San Diego Drainages Hydrogeologic Province, California

    USGS Publications Warehouse

    Wright, Michael T.; Belitz, Kenneth

    2011-01-01

    More than 40 percent of California's drinking water is from groundwater. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State's groundwater quality and increases public access to groundwater-quality information. The San Diego Drainages Hydrogeologic Province (hereinafter referred to as San Diego) is one of the study units being evaluated. The San Diego study unit is approximately 3,900 square miles and consists of the Temecula Valley, Warner Valley, and 12 other alluvial basins (California Department of Water Resources, 2003). The study unit also consists of all areas outside defined groundwater basins that are within 3 kilometers of a public-supply well. The study unit was separated, based primarily on hydrogeologic settings, into four study areas: Temecula Valley, Warner Valley, Alluvial Basins, and Hard Rock (Wright and others, 2005). The sampling density for the Hard Rock study area, which consists of areas outside of groundwater basins, was much lower than for the other study areas. Consequently, aquifer proportions for the Hard Rock study area are not used to calculate the aquifer proportions shown by the pie charts. An assessment of groundwater quality for the Hard Rock study area can be found in Wright and Belitz, 2011. The temperatures in the coastal part of the study unit are mild with dry summers, moist winters, and an average annual rainfall of about 10 inches. The temperatures in the mountainous eastern part of the study unit are cooler than in the coastal part, with an annual precipitation of about 45 inches that occurs mostly in the winter. The primary aquifers consist of Quaternary-age alluvium and weathered bedrock in the Temecula Valley, Warner Valley, and Alluvial Basins study areas, whereas in the Hard Rock study area the primary aquifers consist mainly of fractured and decomposed granite of Mesozoic age. The primary aquifers are defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health (CDPH) database. Public-supply wells typically are drilled to depths between 200 and 700 feet, consist of solid casing from the land surface to a depth of about 60 to 170 feet, and are perforated, or consist of an open hole, below the solid casing. Water quality in the shallow and deep parts of the aquifer system may differ from water quality in the primary aquifers. Municipal water use accounts for approximately 70 percent of water used in the study unit; the majority of the remainder is used for agriculture, industry, and commerce. Groundwater accounts for approximately 8 percent of the municipal supply, and surface water, the majority of which is imported, accounts for the rest. Recharge to groundwater occurs through stream-channel infiltration from rivers and their tributaries, infiltration in engineered recharge basins, and infiltration of water from precipitation and irrigation. The primary source of discharge is water pumped from wells.

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

    USGS Publications Warehouse

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

    1979-01-01

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

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

    USGS Publications Warehouse

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

    2008-01-01

    The U.S. Geological Survey’s Leetown Science Center and the co-located U.S. Department of Agriculture’s National Center for Cool and Cold Water Aquaculture both depend on large volumes of cold clean ground water to support research operations at their facilities. Currently, ground-water demands are provided by three springs and two standby production wells used to augment supplies during periods of low spring flow. Future expansion of research operations at the Leetown Science Center is dependent on assessing the availability and quality of water to the facilities and in locating prospective sites for additional wells to augment existing water supplies. The hydrogeology of the Leetown area, West Virginia, is a structurally complex karst aquifer. Although the aquifer is a karst system, it is not typical of most highly cavernous karst systems, but is dominated by broad areas of fractured rock drained by a relatively small number of solution conduits. Characterization of the aquifer by use of fluorometric tracer tests, a common approach in most karst terranes, therefore only partly defines the hydrogeologic setting of the area. In order to fully assess the hydrogeology and water quality in the vicinity of Leetown, a multi-disciplinary approach that included both fractured rock and karst research components was needed. The U.S. Geological Survey developed this multi-disciplinary research effort to include geologic, hydrologic, geophysical, geographic, water-quality, and microbiological investigations in order to fully characterize the hydrogeology and water quality of the Leetown area, West Virginia. Detailed geologic and karst mapping provided the framework on which hydrologic investigations were based. Fracture trace and lineament analysis helped locate potential water-bearing fractures and guided installation of monitoring wells. Monitoring wells were drilled for borehole geophysical surveys, water-quality sampling, water-level measurements, and aquifer tests to characterize the quality of water and the hydraulic properties of the aquifer. Surface geophysical surveys provided a 3-dimensional view of bedrock resistivity in order to assess geologic and lithologic controls on ground-water flow. Borehole geophysical surveys were conducted in monitoring wells to assess the storage and movement of water in subsurface fractures. Numerous single-well, multi-well, and straddle packer aquifer tests and step-drawdown tests were conducted to define the hydraulic properties of the aquifer and to assess the role of bedrock fractures and solution conduits in the flow of ground water. Water samples collected from wells and springs were analyzed to assess the current quality of ground water and provide a baseline for future assessment. Microbiological sampling of wells for indicator bacteria and human and animal DNA provided an analysis of agricultural and suburban development impacts on ground-water quality. Light detection and ranging (LiDAR) data were analyzed to develop digital elevation models (DEMs) for assessing sinkhole distribution, to provide elevation data for development of a ground-water flow model, and to assess the distribution of major fractures and faults in the Leetown area. The flow of ground water in the study area is controlled by lithology and geologic structure. Bedrock, especially low permeability units such as the shale Martinsburg Formation and the Conococheague Limestone, act as barriers to water flowing down gradient and across bedding. This retardation of cross-strike flow is especially pronounced in the Leetown area, where bedding typically dips at steep angles. Highly permeable fault and fracture zones that disrupt the rocks in cross-strike directions provide avenues through which ground water can flow laterally across or through strata of low primary permeability. Significant strike parallel thrust faults and cross-strike faults typically coincide with larger solution conduits and act as drains for the more pervasive network of interconnected diffuse fractures. Results of borehole geophysical surveys indicate that although numerous fractures may intersect a borehole, only one or two of the fractures typically transmit most of the water to a well. The diffuse-flow dominated network of fractures that provides the majority of storage occupies only a small proportion of the total aquifer volume but constitutes the majority of porosity within the aquifer. Solution conduits, while occupying a relatively small volume of the overall aquifer, are especially important because they serve as primary drains for the ground-water flow system. Surface resistivity maps and cross-sectionsshow anomalous areas of low resistivities coincident with the prevailing geologic strike at N. 20º E., with major cross-strike faults, and with major springs in the region. Transmissivity derived from straddle packer tests was highly variable, and ranged over three orders of magnitude (1.8 x 10-6 to 5.9 x 10-3 ft2/d) in diffuse-flow fractures. A similar large variability in transmissivity was documented by single- and multi-well aquifer tests conducted in conduit-flow dominated portions of the aquifer (2.0 x 103 to 1.4 x 104 ft2/d) in lowland areas immediately adjacent to the Leetown Science Center. A stream-gaging station installed on Hopewell Run near the point where the stream exits the Leetown watershed indicates average daily streamflow for the Hopewell Run of approximately 11.2 ft3/s, and ranged from a minimum of 1.80 ft3/s on September 28, 2005, to a maximum of 73.0 ft3/s on December 11, 2003. Base-flow (ground-water) discharge surveys identified numerous small seeps adjacent to streams in the area. Hydrographs of the stage of Balch Spring show rapid response to individual storms. Strong correlation of the flow of Hopewell Run and Balch Spring indicates the nearby losing stream reach is partly responsible for higher fluctuations in the stage of Balch Spring. A water budget for the study period (2003-2005), based on measured precipitation and hydrograph analyses, is expressed as Precipitation (38.60 in/yr) = Surface Runoff (1.36 in/yr) + Ground-Water Discharge (17.73 in/yr) + Evapotranspiration (24.23 in/yr) – Change in storage (4.72 in/yr). Flow of ground water through the epikarst, a shallow zone of intensely weathered rock and regolith, can be rapid (on the order of days or weeks) as flow is concentrated in solution conduits. Flow within the intermediate and deeper zones is typically much slower. Eight dye-tracer tests conducted in the Leetown area found ground-water flow patterns to be divergent, with velocities ranging from about 12.5 to 610 ft/day and a median velocity of 50 ft/day. Estimates of ground-water age in carbonate rocks in the region are on the order of 15 years in the shallower portions of the aquifer to 50 years or older for deeper portions of the aquifer. Shallow springs can have a significant component of fairly young water ( Ground-water samples collected from 16 sites (12 wells and 4 springs) in the Leetown area were analyzed for more than 340 constituents. Only turbidity, indicator bacteria, and radon were typically present in concentrations exceeding U.S. Environmental Protection Agency (USEPA) drinking-water or aquatic life standards.

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

    NASA Astrophysics Data System (ADS)

    Pashayan, R.

    2007-12-01

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

  13. Field study of hydrogeologic characterization methods in a heterogeneous aquifer.

    PubMed

    Alexander, Matthew; Berg, Steven J; Illman, Walter A

    2011-01-01

    Hydraulic conductivity (K) and specific storage (S(s)) are required parameters when designing transient groundwater flow models. The purpose of this study was to evaluate the ability of commonly used hydrogeologic characterization approaches to accurately delineate the distribution of hydraulic properties in a highly heterogeneous glaciofluvial deposit. The metric used to compare the various approaches was the prediction of drawdown responses from three separate pumping tests. The study was conducted at a field site, where a 15 m × 15 m area was instrumented with four 18-m deep Continuous Multichannel Tubing (CMT) wells. Each CMT well contained seven 17 cm × 1.9 cm monitoring ports equally spaced every 2 m down each CMT system. An 18-m deep pumping well with eight separate 1-m long screens spaced every 2 m was also placed in the center of the square pattern. In each of these boreholes, cores were collected and characterized using the Unified Soil Classification System, grain size analysis, and permeameter tests. To date, 471 K estimates have been obtained through permeameter analyses and 270 K estimates from empirical relationships. Geostatistical analysis of the small-scale K data yielded strongly heterogeneous K fields in three-dimensions. Additional K estimates were obtained through slug tests in 28 ports of the four CMT wells. Several pumping tests were conducted using the multiscreen and CMT wells to obtain larger scale estimates of both K and S(s). The various K and S(s) estimates were then quantitatively evaluated by simulating transient drawdown data from three pumping tests using a 3D forward numerical model constructed using HydroGeoSphere (Therrien et al. 2005). Results showed that, while drawdown predictions generally improved as more complexity was introduced into the model, the ability to make accurate drawdown predictions at all CMT ports was inconsistent. PMID:21671501

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

  15. Hydrogeology of Palm Valley, central Australia; a Pleistocene flora refuge?

    NASA Astrophysics Data System (ADS)

    Wischusen, John D. H.; Fifield, L. Keith; Cresswell, Richard G.

    2004-06-01

    The Palm Valley Oasis (Finke Gorge National Park) in arid central Australia is characterised by large stands of red cabbage palm trees ( Livistona mariae). How these unique plants, over 1000 km away from nearest relatives in the tropical parts of northern Australia persist, has long fascinated visitors. The hydrogeology of this area helps explain this phenomenon. Stable isotope (δ 2H, δ 8O) analyses shows groundwater to have a uniform composition that plots on or near a local meteoric water line. Carbon-14 results are observed to vary throughout this aquifer from effectively dead (<4%) to 87% modern carbon. Ratios of chlorine-36 to chloride range from 130 to 290×10 -1536Cl/Cl. In this region atmospheric 36Cl/Cl ratio is around 300×10 -15. Thus an age range of around 300 ka is indicated if, as is apparent radioactive decay is the only significant cause of 36Cl/Cl variation within the aquifer. The classic homogenous aquifer with varying surface topography flow model is the simplest conceptual model that need be invoked to explain these data. Complexities, associated with local topography flow cells superimposed on the regional gradient, may mean groundwater with markedly different flow path lengths has been sampled. This potential flow path complexity, which is also evidenced by slight variation in groundwater cation ratios, can account for the distribution of isotope age data throughout the aquifer. Given the likely very slow travel times indicated by this aquifer's hydraulic properties, age differences of the magnitude indicated from chlorine-36 data are feasible. The likely slow travel times (>100 ka) along some flow paths indicate groundwater discharge would endure through arid phases associated with Quaternary climate oscillations. Such a flow system can explain the persistence of this population of Palms and also highlight the possibility that Palm Valley has acted as a flora refuge since at least the mid Pleistocene.

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

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

    SciTech Connect

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

    2013-07-01

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

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

    USGS Publications Warehouse

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

    2009-01-01

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

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

    USGS Publications Warehouse

    Glynn, Pierre D.

    2012-01-01

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

  20. Fault control on the hydrogeological setting of the Sibillini Mountains aquifers (Central Apennines, Italy): an example of hydrogeological structures in thrust-belt contexts

    NASA Astrophysics Data System (ADS)

    Tarragoni, C.

    2012-04-01

    This work is aimed at highlighting the importance of fault control on the hydrogeological setting in orogenic areas. In Sibillini Montains, Umbrian-Marchean pelagic succession outcrops. This succession, characterized by calcareous, calcareous-marly and silicate could presents condensed succession and is involved in fold and overthrust deformation, followed by a development of normal faults. The lithostratigraphical and structural study allowed defining the aquifer settings. Several cross-sections have been drawn to identify the three-dimensional geological setting and aquifer's boundaries that consist on: lithological limit between permeable and very low permeable complexes and structural features (groundwater divide and faults). The analyses of principals structural features (e.g. overthrust) have allowed to identify the prominent groundwater flow direction: the Sibillini Montains, Monte Val di Fibbia-P.ta Bambucerta and Visso overthrusts represent three important inverse faults oriented NNW-SSE having aquiclude role due to the high displacement. The altitude gradual decrease forward N of aquiclude handing aquifers combined to Apennine orientation of overthrusts induce a SSE-NNW groundwater flow. A detailed analysis of base flow has allowed to: 1) define the river's base flow; 2) recognize the punctual, diffused and linear springs; 3) quantify the water resource on average drained; and 4) determine the discharge regime of springs and rivers. The geologic-structural analyses with the quantitative hydrogeological studies have allowed to prepare the Conceptual Hydrogeological Model (CHM) and to calculate the hydrogeological balance for each aquifer. This double approach let to carry out a detailed study and make out hypotheses about groundwater circulation for each aquifer. These hypotheses represent the bases for the groundwater modelling that could give an important contribute to confirm or not them. The CHM of main aquifer has been adopted to carry out the groundwater numerical simulation. Modelling validation has been performed through the matching between the experimental and calculated discharge values, between the piezometric field and topography (the calculated piezometric field always resulting above the spring altitude and below the hydrographical network without base flow) and between the piezometric field and altitude of aquiclude that limits the aquifer. If one of these three conditions is not verified the model is not realistic and the hypotheses must be rejected. In two cases the modelling results suggested a revision of the assumptions and only through a depth structural analysis has been possible to estimate the real role of Vettore Mont normal fault and recognize a secondary fault that divide an aquifer. In conclusion this study represents an example of necessary combination between structural and hydrogeological analyses and underlines the importance of information exchange and/or cooperation to allow the 3-D reconstruction of hydrogeological setting.

  1. Nomenclature of regional hydrogeologic units of the Southeastern Coastal Plain aquifer system

    USGS Publications Warehouse

    Miller, J.A.; Renken, R.A.

    1988-01-01

    Clastic sediments of the Southeastern Coastal Plain aquifer system can be divided into four regional aquifers separated by three regional confining units. The four regional aquifers have been named for major rivers that cut across their outcrop areas and expose the aquifer materials. From youngest to oldest, the aquifers are called the Chickasawhay River, Pearl River, Chattahoochee River, and Black Warrior River aquifers, and the regional confining units separating them are given the same name as the aquifer they overlie. Most of the regional hydrogeologic units are subdivided within each of the four States that comprise the study area. Correlation of regional units is good with hydrogeologic units delineated by a similar regional study to the west and southwest. Because of complexity created by a major geologic structure to the northeast of the study area and dramatic facies change from clastic to carbonate strata to the southeast, correlation of regional hydrogeologic units is poor in these directions. (Author 's abstract)

  2. Theoretical principles of petroleum hydrogeology of the West Siberian megabasin (WSMB)

    NASA Astrophysics Data System (ADS)

    Matusevich, V.; Popov, V.; Kovyatkina, L.; Pozdeeva, G.

    2016-03-01

    Comprehensive study of the chemical and gas composition, temperatures, levels, pressure of deep underground water in deep wells is associated with the beginning of the systematic development of the oil and gas potential in Western Siberia and the first discovery of large deposits here. The development of new branches of hydrogeology is due to the fact of more and more available data. Thus, fundamental understandings of the WSMB hydrogeological conditions are being translated into new theories. Geodynamically, the WSMB structure was revised and based on hydrogeological data, regional and local prediction of oil and gas occurrence exploration criteria were developed. Based on the dispersion halo water-dissolved substance theory, exploration methodology of “neglected” deposits were formulated, conceptual issues of technogenic changes of oil and gas hydrogeosphere areas were being developed.

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

    SciTech Connect

    Weaver, B.

    1994-12-31

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

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

    USGS Publications Warehouse

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

    1970-01-01

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

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

    SciTech Connect

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

    1992-03-31

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

  6. Hydrogeological influences on radionuclide migration from the major radioactive waste burial sites at Chernobyl (A review)

    SciTech Connect

    Dgepo, S.P.; Skalsky, A.S.; Bugai, D.A.; Marchuk, V.V.; Waters, R.D.

    1994-03-01

    This paper summarizes the recent hydrogeological investigations of several research organizations on waste confinement at the major radioactive waste (RW) burial sites immediately adjacent to the Chernobyl Nuclear Power Plant (Ch. NPP). Hydrogeological conditions and radiologic ground-water contamination levels are described. Ongoing ground-water monitoring practices are evaluated. The chemical and physical characteristics of the radionuclides within the burial sites are considered. Ground water and radionuclide transport modeling studies related to problems of the RW disposal sites are also reviewed. Current concerns on future impacts of the RW burial sites on the hydrological environment and water resources of the Ch.NPP area are discussed.

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

    SciTech Connect

    Shafer, John M

    2012-11-05

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

  8. A Task-oriented Approach for Hydrogeological Site Characterization

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

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

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

    NASA Astrophysics Data System (ADS)

    Ko, K.; Suk, H.

    2009-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2005-12-01

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

  12. Combined Estimation of Hydrogeologic Conceptual Model and Parameter Uncertainty

    SciTech Connect

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

    2004-03-01

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

  13. 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...

  14. Geologic framework and hydrogeologic characteristics of the Edwards Aquifer recharge zone, Bexar County, Texas

    USGS Publications Warehouse

    Stein, W.G.; Ozuna, G.B.

    1995-01-01

    In Bexar County, residential and commercial development on the Edwards aquifer recharge zone is increasing. The aquifer possibly can be contaminated by spills, leakage of hazardous materials, or runoff from the rapidly developing urban areas that surround, or are built on, the intensely faulted and fractured, karstic limestone outcrops characteristic of the recharge zone. Furthermore, some of the hydrogeologic subdivisions that compose the Edwards aquifer have greater effective porosity than others. The areas where the most porous subdivisions crop out might provide efficient avenues for contaminants to enter the aquifer. The Edwards aquifer recharge zone has relatively large permeability resulting, in part, from the development or redistribution of secondary porosity. Lithology, stratigraphy, diagenesis, and karstification account for the effective porosity and permeability in the Edwards aquifer outcrop. Karst features that greatly enhance effective porosity in the outcrop area include sinkholes and caves. Hydrogeologic subdivision VI, the Kirschberg evaporite member, appears to be the most porous and permeable subdivision within the Kainer Formation. Hydrogeologic subdivision III, the leached and collapsed members, undivided, is the most porous and permeable subdivision within the Person Formation. Hydrogeologic subdivision II, the cyclic and marine members,.undivided, is moderately permeable, with both fabric- and not-fabric-selective porosity. The faults in northern Bexar County are part of the Balcones fault zone. Although most of the faults in this area trend northeast, a smaller set of cross-faults trend northwest. Generally, the faults are en echelon and normal, with the downthrown blocks typically toward the coast.

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

    ERIC Educational Resources Information Center

    Singha, Kamini; Loheide, Steven P., II

    2011-01-01

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

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

    USGS Publications Warehouse

    Back, W.; Herman, J.S.

    1997-01-01

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

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

    EPA Science Inventory

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

  18. 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...

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

    SciTech Connect

    Daly, D.J.; Schmit, C.R.; Beaver, F.W.; Evans, J.M. )

    1989-09-01

    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.

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

    USGS Publications Warehouse

    Friedel, Michael J.

    2008-01-01

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    ERIC Educational Resources Information Center

    Singha, Kamini; Loheide, Steven P., II

    2011-01-01

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

  3. Geologic framework and hydrogeologic characteristics of the Edwards Aquifer outcrop, Hays County, Texas

    USGS Publications Warehouse

    Hanson, John A.; Small, Ted A.

    1995-01-01

    All of the hydrogeologic subdivisions within the Edwards aquifer outcrop in Hays County have some porosity and permeability. The most porous and permeable appear to be hydrogeologic subdivision VI, the Kirschberg evaporite member of the Kainer Formation; hydrogeologic subdivision III, the leached and collapsed members, undivided; and hydrogeologic subdivision II, the cyclic and marine members, undivided, of the Person Formation. The two types of porosity in the Edwards aquifer outcrop are fabric selective, which is related to depositional or diagenetic elements and typically exists in specific stratigraphic horizons; and not fabric selective, which can exist in any lithostratigraphic horizon. Permeability, the capacity of porous rock to transmit water, depends on the physical properties of the rock such as size, shape, and distribution of pores, and fissuring and dissolution. Two faults, San Marcos Springs and Mustang Branch, completely, or almost completely, offset the Edwards aquifer by juxtaposing Edwards aquifer limestone against nearly impermeable upper confining units along parts of their traces across Hays County. These faults are thought to be barriers, or partial barriers, to ground-water flow where the beds are juxtaposed. In Hays County, the Edwards aquifer probably is most vulnerable to surface contamination in the rapidly urbanizing areas on the Edwards aquifer outcrop. Contamination can result from spills or leakage of hazardous materials; or runoff on the intensely faulted and fractured, karstic limestone outcrops characteristic of the recharge zone.

  4. Hydrogeologic Factors Influencing Denitrification in Atlantic Coastal Plain Surficial Aquifers

    NASA Astrophysics Data System (ADS)

    Puckett, L. J.

    2001-05-01

    A series of flow system studies were conducted in Georgia, South Carolina, and North Carolina to examine the potential for removal of nitrate by denitrification in settings that differed from those previously examined at a site in Maryland. Surficial aquifers of the Atlantic Coastal Plain consist primarily of late Tertiary and Quaternary marine deposits of sand and silty sand. These aquifers generally are less than 15 m thick over much of their extent, but may be thicker in the Delmarva Peninsula and Florida. Typically these aquifers contain little buried organic matter and soil organic carbon content is also low. Most organic rich soils and sediments are limited to alluvial valleys. The combination of relatively flat terrain, highly permeable sediments, little organic matter, and moderate excess precipitation and nitrogen inputs, results in aquifers that are susceptible to nitrate contamination. At the Georgia site, median nitrate concentration was 1.6 mg/L in ground water, 7.3 mg/L in ditches and drains, below detection under the stream, and 1.1 mg/L in the stream. Clay layers in the sandy residuum at the Georgia site prevented nitrate from leaching into the ground water, routing it instead through drains and ditches to the stream. At the South Carolina site, the median nitrate concentration was 5.8 mg/L in ground water, 3.3 mg/L under the stream, and 1.8 mg/L in the stream. Denitrification took place at some locations at the South Carolina site, but nitrate passed under a riparian forest and discharged into the stream. In North Carolina, the median nitrate concentration was 21.5 mg/L in ground water, below detection under the stream, and 1.8 mg/L in the stream. Organic rich sediments near the stream at the North Carolina site contributed to complete denitrification in ground water before it reached the stream. At the comparison site in Maryland, median nitrate concentrations were 9.8 mg/L in ground water, 4.7 mg/L under the stream, and 9.6 mg/L in the stream. Nitrate at a second Maryland site was 14 mg/L in ground water, below detection under the stream, and 2.5 mg/L in the stream. At the Maryland sites, nitrate in ground water passed under the riparian forest and discharged into the stream at one location whereas at the other site it was denitrified as ground water was forced through organic rich, near stream sediments by a shallow confining layer. These results suggest that factors such as hydrogeology and aquifer origins and depositional history are important in determining whether and where denitrification will occur.

  5. Hydrogeological modelling as a tool for understanding rockslides evolution

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  6. Hydrogeological characterization of a coastal aquifer in southern Turkey

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  8. An Assessment of Current Concepts for Hydrogeological Site Characterization, and Alternatives

    NASA Astrophysics Data System (ADS)

    Rubin, Y.; Barros, F.

    2007-05-01

    Characterization of the geological and hydrogeological conditions of contaminated sites is a critical element of risk management. Characterization includes data acquisition and interpretation that intends to provide the analytical tools needed for decision making related to transport of contaminants and for remediation. Despite many years of experience, site characterization is still not as well understood and regulated as it should be. The chasm between some of the newer concepts developed by researchers on the one hand, and the technology used in the field by service providers on the other, has never been wider than it is today. Consequently, questions that should be addressed using well-documented rational tools may continue to be addressed based on intuition and experience. Instead of coming up with defensible action plans and implementing them rapidly, such action plans are often a source of contention and end up in the courts. This paper evaluates concepts often used in the practice of hydrogeological site characterization, and tries to distinguish between myth and reality. It explores concepts such as: 1. Accurate descriptions of geological and hydrogeological conditions are attainable; 2. Sound planning and action plans in response to accidents require a large amount of data; 3. Investing in site characterization is a sound investment; 4. Experience gained in decontamination and decommissioning in the field is a sound basis for planning future efforts; 5. If you do not find the contaminants, they do not exist; 6. Numerical models for flow and transport processes in the subsurface are beneficial; 7. Current regulations in the area of hydrogeology are helpful. These concepts, while often invoked in applications, are often wrong and misleading or applied incorrectly, and reflect the many ambiguities prevailing in this area. This paper explores the issues raised above in detail. It also presents the elements of a consistent approach for site characterization, and demonstrates it through a case study that involves uncertainty in the hydrogeology as well as in human physiology.

  9. Hydrogeological properties of bank storage area in Changwon city, Korea

    NASA Astrophysics Data System (ADS)

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

    2003-04-01

    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 correlation. However, storativity values obtained by the two cases show distinct negative correlation. ACKNOWLEDGEMENT The authors wish to acknowledge the financial support of the Sustainable Water Resources Research Center under the program of the 21st Century Frontier R&D Program by the Korean government (project no: 3-4-1).

  10. Hydrogeology of the gray limestone aquifer in southern Florida

    USGS Publications Warehouse

    Reese, Ronald S.; Cunningham, Kevin J.

    2000-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

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

    USGS Publications Warehouse

    Thomas, Blakemore E.

    2006-01-01

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

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

    USGS Publications Warehouse

    Lampe, David C.

    2009-01-01

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

  15. Preliminary stratigraphic and hydrogeologic cross sections and seismic profile of the Floridan aquifer system of Broward County, Florida

    USGS Publications Warehouse

    Reese, Ronald S.; Cunningham, Kevin J.

    2013-01-01

    To help water-resource managers evaluate the Floridan aquifer system (FAS) as an alternative water supply, the U.S. Geological Survey initiated a study, in cooperation with the Broward County Environmental Protection and Growth Management Department, to refine the hydrogeologic framework of the FAS in the eastern part of Broward County. This report presents three preliminary cross sections illustrating stratigraphy and hydrogeology in eastern Broward County as well as an interpreted seismic profile along one of the cross sections. Marker horizons were identified using borehole geophysical data and were initially used to perform well-to-well correlation. Core sample data were integrated with the borehole geophysical data to support stratigraphic and hydrogeologic interpretations of marker horizons. Stratigraphic and hydrogeologic units were correlated across the county using borehole geophysical data from multiple wells. Seismic-reflection data were collected along the Hillsboro Canal. Borehole geophysical data were used to identify and correlate hydrogeologic units in the seismic-reflection profile. Faults and collapse structures that intersect hydrogeologic units were also identified in the seismic profile. The information provided in the cross sections and the seismic profile is preliminary and subject to revision.

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

    SciTech Connect

    Feckley, D.L. . Geology Dept.)

    1993-02-01

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

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

    USGS Publications Warehouse

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

    1993-01-01

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

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

    SciTech Connect

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

    1986-01-01

    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.

  19. Hydrogeologic framework of sedimentary deposits in six structural basins, Yakima River basin, Washington

    USGS Publications Warehouse

    Jones, M.A.; Vaccaro, J.J.; Watkins, A.M.

    2006-01-01

    The hydrogeologic framework was delineated for the ground-water flow system of the sedimentary deposits in six structural basins in the Yakima River Basin, Washington. The six basins delineated, from north to south are: Roslyn, Kittitas, Selah, Yakima, Toppenish, and Benton. Extent and thicknesses of the hydrogeologic units and total basin sediment thickness were mapped for each basin. Interpretations were based on information from about 4,700 well records using geochemical, geophysical, geologist's or driller's logs, and from the surficial geology and previously constructed maps and well interpretations. The sedimentary deposits were thickest in the Kittitas Basin reaching a depth of greater than 2,000 ft, followed by successively thinner sedimentary deposits in the Selah basin with about 1,900 ft, Yakima Basin with about 1,800 ft, Toppenish Basin with about 1,200 ft, Benton basin with about 870 ft and Roslyn Basin with about 700 ft.

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

    USGS Publications Warehouse

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

    2008-01-01

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

  1. Digital surfaces and thicknesses of selected hydrogeologic units within the Ozark Plateaus aquifer system, northwestern Arkansas

    USGS Publications Warehouse

    Czarnecki, John B.; Bolyard, Susan E.; Hart, Rheannon M.; Clark, Jimmy M.

    2014-01-01

    Digital surfaces and thicknesses of nine hydrogeologic units of the Ozark Plateaus aquifer system from land surface to the top of the Gunter Sandstone in northwestern Arkansas were created using geophysical logs, drillers’ logs, geologist-interpreted formation tops, and previously published maps. The 6,040 square mile study area in the Ozark Plateaus Province includes Benton, Washington, Carroll, Madison, Boone, Newton, Marion, and Searcy Counties. The top of each hydrogeologic unit delineated on geophysical logs was based partly on previously published reports and maps and also from drillers’ logs. These logs were then used as a basis to contour digital surfaces showing the top and thickness of the Fayetteville Shale, the Boone Formation, the Chattanooga Shale, the Everton Formation, the Powell Dolomite, the Cotter Dolomite, the Roubidoux Formation, the Gasconade Dolomite, and the Gunter Sandstone.

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

    USGS Publications Warehouse

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

    1997-01-01

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

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

    PubMed

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

    2012-06-15

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

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

    USGS Publications Warehouse

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

    1978-01-01

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

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

    USGS Publications Warehouse

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

    2005-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Frampton, Andrew; Dessirier, Benoit; Pannetier, Romain

    2014-05-01

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

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

    NASA Astrophysics Data System (ADS)

    Nawalany, Marek; Sinicyn, Grzegorz

    2015-09-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

  9. Modeling of changing hydrogeological conditions during construction of pier foundations on the Kama river bank

    NASA Astrophysics Data System (ADS)

    Purgina, D.; Strokova, L.; Kuzevanov, K.

    2016-03-01

    The article presents the results of hydrogeological studies carried out within the area of the Kama river bank in Perm city. It proposes the hydrodynamic model by means of which a number of forecasting issues have been addressed. The possible scenarios of changes in filtration flow, i.e. water rise before the obstacle and water drop behind the obstacle due to groundwater filtration blockage, have been described [2]. The allowable changes of hydrodynamic conditions within the study area have been outlined.

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

    SciTech Connect

    Reynolds, R.; Nowacki, P.

    1991-04-01

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

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

    SciTech Connect

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

    2009-04-20

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

    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.

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

    SciTech Connect

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

    1989-01-01

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

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

    NASA Astrophysics Data System (ADS)

    shiuan, C. W.; Chang, L.

    2013-12-01

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

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

    NASA Astrophysics Data System (ADS)

    Addison, Adrian Demond

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

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

    USGS Publications Warehouse

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

    1991-01-01

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

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

    PubMed

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

    2013-12-15

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

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

    SciTech Connect

    Liikala, T.L.

    1994-09-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-10-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2001-04-01

    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.

  1. Structure and genesis of the Cubango Megafan in northern Namibia: implications for its hydrogeology

    NASA Astrophysics Data System (ADS)

    Lindenmaier, F.; Miller, R.; Fenner, J.; Christelis, G.; Dill, H. G.; Himmelsbach, T.; Kaufhold, S.; Lohe, C.; Quinger, M.; Schildknecht, F.; Symons, G.; Walzer, A.; van Wyk, B.

    2014-09-01

    An exploration strategy for groundwater was established and followed in the northern Namibian Cuvelai-Etosha Basin (CEB). The data derived from transient electromagnetics, rotary-drilling, coring and sample investigation were used to refine stratigraphy and hydrostratigraphy, and to develop a 3D map of aquifers within the Cubango Megafan. The results have delineated three major aquifers. The newly found, deep-seated Ohangwena II Aquifer (KOH-2) has the potential of providing significant additional water to the water supply of northern Namibia and Angola. While near-surface aquifers carry predominantly brackish water, freshwater in the deep-seated aquifer is further extended and features good hydraulic properties. To date, only a small part of the hydrogeological potential of arid CEB has been explored and an extension of exploration is needed, including southern Angola. The combination of structural, sedimentological and hydrogeological approaches greatly advanced both the geological and hydrogeological understanding. With regard to the deep-seated aquifer, strict measures need to be applied to ensure that the water in the KOH-2 reservoir is exploited sustainably. Water control areas need to be established to ensure long-term preservation of this newly explored aquifer.

  2. Geologic framework and hydrogeologic characteristics of the Edwards Aquifer outcrop, Medina County, Texas

    USGS Publications Warehouse

    Small, Ted A.; Clark, Allan K.

    2000-01-01

    The hydrogeologic subdivisions of the Edwards aquifer outcrop in Medina County generally are porous and permeable. The most porous and permeable appear to be hydrogeologic subdivision VI, the Kirschberg evaporite member of the Kainer Formation; and hydrogeologic subdivision III, the leached and collapsed members, undivided, of the Person Formation. The most porous and permeable rocks of the Devils River Formation in Medina County appear to be in the top layer. The upper member of the Glen Rose Limestone, the lower confining unit, has much less porosity and permeability than that observed in the Edwards aquifer. The Edwards aquifer has relatively large porosity and permeability resulting, in part, from the development or redistribution of secondary porosity. Lithology, stratigraphy, diagenesis, and karstification account for the effective porosity and permeability in the Edwards aquifer outcrop. Karst features that can greatly enhance effective porosity and permeability in the Edwards aquifer outcrop include sinkholes, dolines, and caves. The Edwards aquifer rocks in Medina County change from the eight-member Edwards Group to the essentially indivisible Devils River Formation. The facies change occurs along a line extending northwestward from just south of Medina Lake.

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

    SciTech Connect

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

    1996-09-01

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

  4. A geophysical and hydrogeological study of aquifers contamination by a landfill

    NASA Astrophysics Data System (ADS)

    Senos Matias, M.; Marques da Silva, M.; Ferreira, P.; Ramalho, E.

    1994-08-01

    Landfills are the classical solution for waste disposal. During the last years there has been a growing concern about the effect of landfills in public health, because leaching water can contaminate nearby aquifers. Hydrogeological studies are very important to investigate and remedy these contamination problems but an integrated use of both geophysical and hydrological methods can be even more effective. In this paper, the groundwater contamination by a landfill, located on very porous and permeable formations, is assessed by both geophysical and hydrogeological techniques. Bearing in mind the geological and hydrogeological characteristics of the area, electrical methods were chosen to carry out the geophysical survey. At first, electromagnetic methods were used and a ground conductivity survey was carried out to determine the contamination plume. Then several resistivity soundings were proposed and two resistivity pseudo-sections obtained so that a more detailed study of the contamination was accomplished. From the geophysical data interpretation, strategically located boreholes were drilled, water samples obtained and chemical analysis carried out. Finally, the overall results are integrated and discussed as well as the merits and disadvantages of the techniques that have been employed.

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

    SciTech Connect

    T. Miller

    2004-11-15

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

  6. 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)

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

    2001-12-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

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

    USGS Publications Warehouse

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

    2013-01-01

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

  9. 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)

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

    2010-05-01

    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.

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

    USGS Publications Warehouse

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

    1995-01-01

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

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

    SciTech Connect

    Saegusa, Hiromitsu; Onoe, Hironori; Takeuchi, Shinji; Takeuchi, Ryuji; Ohyama, Takuya

    2007-07-01

    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)

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

    NASA Astrophysics Data System (ADS)

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

    2007-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  14. Hydrogeologic framework and sampling design for an assessment of agricultural pesticides in ground water in Pennsylvania

    USGS Publications Warehouse

    Lindsey, Bruce D.; Bickford, Tammy M.

    1999-01-01

    State agencies responsible for regulating pesticides are required by the U.S. Environmental Protection Agency to develop state management plans for specific pesticides. A key part of these management plans includes assessing the potential for contamination of ground water by pesticides throughout the state. As an example of how a statewide assessment could be implemented, a plan is presented for the Commonwealth of Pennsylvania to illustrate how a hydrogeologic framework can be used as a basis for sampling areas within a state with the highest likelihood of having elevated pesticide concentrations in ground water. The framework was created by subdividing the state into 20 areas on the basis of physiography and aquifer type. Each of these 20 hydrogeologic settings is relatively homogeneous with respect to aquifer susceptibility and pesticide use?factors that would be likely to affect pesticide concentrations in ground water. Existing data on atrazine occurrence in ground water was analyzed to determine (1) which areas of the state already have suffi- cient samples collected to make statistical comparisons among hydrogeologic settings, and (2) the effect of factors such as land use and aquifer characteristics on pesticide occurrence. The theoretical vulnerability and the results of the data analysis were used to rank each of the 20 hydrogeologic settings on the basis of vulnerability of ground water to contamination by pesticides. Example sampling plans are presented for nine of the hydrogeologic settings that lack sufficient data to assess vulnerability to contamination. Of the highest priority areas of the state, two out of four have been adequately sampled, one of the three areas of moderate to high priority has been adequately sampled, four of the nine areas of moderate to low priority have been adequately sampled, and none of the three low priority areas have been sampled. Sampling to date has shown that, even in the most vulnerable hydrogeologic settings, pesticide concentrations in ground water rarely exceed U.S. Environmental Protection Agency Drinking Water Standards or Health Advisory Levels. Analyses of samples from 1,159 private water supplies reveal only 3 sites for which samples with concentrations of pesticides exceeded drinking-water standards. In most cases, samples with elevated concentrations could be traced to point sources at pesticide loading or mixing areas. These analyses included data from some of the most vulnerable areas of the state, indicating that it is highly unlikely that pesticide concentrations in water from wells in other areas of the state would exceed the drinking-water standards unless a point source of contamination were present. Analysis of existing data showed that water from wells in areas of the state underlain by carbonate (limestone and dolomite) bedrock, which commonly have a high percentage of corn production, was much more likely to have pesticides detected. Application of pesticides to the land surface generally has not caused concentrations of the five state priority pesticides in ground water to exceed health standards; however, this study has not evaluated the potential human health effects of mixtures of pesticides or pesticide degradation products in drinking water. This study also has not determined whether concentrations in ground water are stable, increasing, or decreasing.

  15. What maintains the waters flowing in our rivers? - Rethinking hydrogeology to improve public policy

    NASA Astrophysics Data System (ADS)

    Vasconcelos, Vitor Vieira

    2016-01-01

    This article discusses how new contributions from hydrogeological science in the 20th and 21st centuries have allowed for a better understanding of the processes that affect the maintenance of river flows. Moreover, the way in which this knowledge has been conveyed beyond academia and has been gradually incorporated into public policy for natural resource management is also discussed. This article explains the development of several approaches used to understand the relationships among the management of aquifers, vegetation and river flows, including water balance, aquifer recharge, the piston effect, seasonal effects, and safe and sustainable yields. Additionally, the current challenges regarding the modeling of hydrological processes that integrate groundwater and surface waters are discussed. Examples of studies applied in Brazil that demonstrate these processes and stimulate thought regarding water management strategies are presented. In light of the case studies, it is possible to propose different strategies, each adapted for specific hydrogeological context to maximize aquifer recharge or base flow maintenance. Based on these strategies, the role of infiltration ponds and other artificial recharge techniques is re-evaluated in the context of the mitigation of environmental impacts on the maintenance of river flows. Proposals for the improvement of public policies regarding the payment of related environmental services to stimulate investment in aquifer recharge and the maintenance of base flow, for which the goal is to attain win-win-win situations for the environment, farmers and water users, while preventing land speculation, are discussed. Lastly, a conceptual model for the dissemination of hydrogeological knowledge in public policies is provided, and its challenges and possibilities are discussed.

  16. The Impact of Hsueh-Shan Tunnel Construction on the Hydrogeological Environment in Northern Taiwan

    NASA Astrophysics Data System (ADS)

    Chiu, Y.; Chia, Y.

    2010-12-01

    The Hsueh-Shan tunnel, the fourth longest tunnel in the world, was suffered many collapses due to huge groundwater ingression and was ultimately opened to the public in June, 2006, after 15-year construction. Since the commencement of construction of tunnel, a long-term monitoring project to measure the groundwater ingression into the tunnel was conducted to ensure the safety of tunnel structure. According to the measured data obtained from the monitoring project, the average total flux of ingressive groundwater is about 450 l/sec. In order to assess the influence of this huge amount of ingressive groundwater on the regional hydrogeology near the tunnel area, a hydrogeological conceptual model was developed. We use MODFLOW-2005 to simulate groundwater flow and use the automated parameter estimation method to calibrate the model. The data on geography, geological structure, and groundwater hydrology are compiled to develop the conceptual model and the measured flux of ingressive groundwater is used to calibrate the model. The regional hydrogeological characteristics, before and after the tunnel excavation, and the water resources are evaluated by this calibrated conceptual model. The result shows that the ingression of groundwater into the tunnel is almost reach the steady state and the total amount of water is mainly contributed by about 2% loss of the total inflow of the Feitsui Reservoir. Besides, the condition of linings in the tunnel plays an important role in the safety of tunnel structure. Therefore, the long-term monitoring project should be continuously conducted to ensure the distribution of water resources and the safety of tunnel structure.

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

    USGS Publications Warehouse

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

    2005-01-01

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

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

    USGS Publications Warehouse

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

    1997-01-01

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

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

    SciTech Connect

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

    2002-07-09

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

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

    SciTech Connect

    McLane, C.F. III; Whidden, J.A.; Hopkins, J.K.

    1998-07-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2003-01-01

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

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

    PubMed

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

    2003-01-01

    The heterogeneity of hydrogeologic properties at different scales may have different effects on flow and transport processes in a subsurface system. A model for the unsaturated zone of Yucca Mountain, Nevada, is developed to represent complex heterogeneity at two different scales: (1) layer scale corresponding to geologic layering and (2) local scale. The layer-scale hydrogeologic properties are obtained using inverse modeling, based on the available measurements collected from the Yucca Mountain site. Calibration results show a significant lateral and vertical variability in matrix and fracture properties. Hydrogeologic property distributions in a two-dimensional, vertical cross-section of the site are generated by combining the average layer-scale matrix and fracture properties with local-scale perturbations generated using a stochastic simulation method. The unsaturated water flow and conservative (nonsorbing) tracer transport through the cross-section are simulated for different sets of matrix and fracture property fields. Comparison of simulation results indicates that the local-scale heterogeneity of matrix and fracture properties has a considerable effect on unsaturated flow processes, leading to fast flow paths in fractures and the matrix. These paths shorten the travel time of a conservative tracer from the source (repository) horizon in the unsaturated zone to the water table for small fractions of total released tracer mass. As a result, the local-scale heterogeneity also has a noticeable effect on global tracer transport processes, characterized by an average breakthrough curve at the water table, especially at the early arrival time of tracer mass. However, the effect is not significant at the later time after 20% tracer mass reaches the water table. The simulation results also verify that matrix diffusion plays an important role in overall solute transport processes in the unsaturated zone at Yucca Mountain. PMID:12498572

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

    NASA Astrophysics Data System (ADS)

    James, Bruce R.; Freeze, R. Allan

    1993-07-01

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

  4. A review of non-invasive imaging methods and applications in contaminant hydrogeology research.

    PubMed

    Werth, Charles J; Zhang, Changyong; Brusseau, Mark L; Oostrom, Mart; Baumann, Thomas

    2010-04-01

    Contaminant hydrogeological processes occurring in porous media are typically not amenable to direct observation. As a result, indirect measurements (e.g., contaminant breakthrough at a fixed location) are often used to infer processes occurring at different scales, locations, or times. To overcome this limitation, non-invasive imaging methods are increasingly being used in contaminant hydrogeology research. Four of the most common methods, and the subjects of this review, are optical imaging using UV or visible light, dual-energy gamma radiation, X-ray microtomography, and magnetic resonance imaging (MRI). Non-invasive imaging techniques have provided valuable insights into a variety of complex systems and processes, including porous media characterization, multiphase fluid distribution, fluid flow, solute transport and mixing, colloidal transport and deposition, and reactions. In this paper we review the theory underlying these methods, applications of these methods to contaminant hydrogeology research, and methods' advantages and disadvantages. As expected, there is no perfect method or tool for non-invasive imaging. However, optical methods generally present the least expensive and easiest options for imaging fluid distribution, solute and fluid flow, colloid transport, and reactions in artificial two-dimensional (2D) porous media. Gamma radiation methods present the best opportunity for characterization of fluid distributions in 2D at the Darcy scale. X-ray methods present the highest resolution and flexibility for three-dimensional (3D) natural porous media characterization, and 3D characterization of fluid distributions in natural porous media. And MRI presents the best option for 3D characterization of fluid distribution, fluid flow, colloid transport, and reaction in artificial porous media. Obvious deficiencies ripe for method development are the ability to image transient processes such as fluid flow and colloid transport in natural porous media in three dimensions, the ability to image many reactions of environmental interest in artificial and natural porous media, and the ability to image selected processes over a range of scales in artificial and natural porous media. PMID:20163885

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

    SciTech Connect

    Sanford, R.F. )

    1990-11-01

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

  6. The Evolution of the Hydrogeologic System in the Taipei Basin, Northern Taiwan

    NASA Astrophysics Data System (ADS)

    Lin, M.; Chia, Y.

    2011-12-01

    Taipei basin is the largest metropolitain area in Taiwan, and thus the change of its hydrogeologic system is closely associated with the economic development of the urban area. In this study, we integrated the core data and groundwater level data to construct the hydrogeologic framework of the Taipei basin. Then the long-term elevation data and groundwater data were analyzed to understand the impact of urban development on the hydrogeologic system. By analyzing the long-term change of groundwater level in the Taipei basin, we found two groups of wells with a different range of water level and pattern of water level variation. The first group of wells is relatively shallow. Their hydraulic heads fluctuated between 0 and 5m. Generally the water level is rarely affected by pumping, but sensitive to the rainfall. These wells were placed in sand layers of the Songshan formation. However, the second group of wells, where the hydraulic head ranges from -40m to 0m, is relatively deep. They were installed in the Jingmei formation and Wugu formation. Pumping activities have significantly influenced the change in groundwater level. For these reasons, we proposed two hydrogeologic units in the Taipei basin. One is the Songshan aquifer characterized by interbeded local aquifer and aquitard. The other is the Taipei aquifer which combines the lower Songshan formation, Jingmei formation, and Wugu formation. Extensive pumping from the Taipei aquifer has caused serious land subsidence since the rapid expansion of the urban area in 1950s. The cumulative amount of settlement in the Taipei basin is about 2.2 m by 1983. The subsidence appeared to be inelastic with little recovery. The groundwater level has declined approximately 50 m by 1976. The decline was followed by a rapid recovery in the Taipei aquifer starting from late 1970s. In the past two decades, however, small subsidence ranging from 3~5 cm have been induced by the extensive pumping during the construction of Metro system. The elevation of the land surface usually fully recovered shortly after a rapid natural recharge following the pumping. Thus, the uplift after the land subsidence became elastic rebound phenomenon. Therefore, the change in groundwater level of the Taipei Aquifer becomes the primary factor controlling the elevation of land surface.

  7. Masteŕ s Programme at Stockholm University: Hydrology, Hydrogeology and Water Resources

    NASA Astrophysics Data System (ADS)

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

    2009-04-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

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

  9. Development of hydrogeological modelling approaches for assessment of consequences of hazardous accidents at nuclear power plants

    SciTech Connect

    Rumynin, V.G.; Mironenko, V.A.; Konosavsky, P.K.; Pereverzeva, S.A.

    1994-07-01

    This paper introduces some modeling approaches for predicting the influence of hazardous accidents at nuclear reactors on groundwater quality. Possible pathways for radioactive releases from nuclear power plants were considered to conceptualize boundary conditions for solving the subsurface radionuclides transport problems. Some approaches to incorporate physical-and-chemical interactions into transport simulators have been developed. The hydrogeological forecasts were based on numerical and semi-analytical scale-dependent models. They have been applied to assess the possible impact of the nuclear power plants designed in Russia on groundwater reservoirs.

  10. Hydrogeologic and water-quality data for the main site, Naval Surface Warfare Center, Dahlgren Laboratory, Dahlgren, Virginia

    USGS Publications Warehouse

    Bell, Clifton F.; Bolles, Thomas P.; Harlow,, George E., Jr.

    1994-01-01

    Hydrogeologic and water-quality data were collected at the Naval Surface Warfare Center, Dahlgren Laboratory at Dahlgren, Virginia, as part of a hydrogeologic assessment of the shallow aquifer system begun in 1992. The U.S. Geological Survey conducted this study to provide the Navy with hydrogeologic data to meet the requirements of a Spill Contingency Plan. This report describes the ground-water observation-well network, hydro- geologic, and water-quality data collected between August 1992 and September 1993. The report includes a description of the locations and con- struction of 35 observation wells on the Main Site. Hydrologic data include lithologic core samples, geophysical logs, and vertical hydraulic conductivity measurements of selected core intervals. Hydrologic data include synoptic and hourly measurements of ground-water levels, observation-well slug tests to determine horizontal hydraulic conductivity, and tide data. Water-quality data include analyses of major dissolved constituents in ground water and surface water.

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

    USGS Publications Warehouse

    Small, Ted A.; Lambert, Rebecca B.

    1998-01-01

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

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

    USGS Publications Warehouse

    Anderman, Evan R.; Hill, Mary C.

    2003-01-01

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

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

    PubMed Central

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

    2015-01-01

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

  14. Actualization of the Hydrogeological Model of the Ojos Negros VALLEY\\'{ }s Aquifer

    NASA Astrophysics Data System (ADS)

    Campos-Gaytan, J.; Vazquez Gonzalez, R.

    2002-12-01

    A regional groundwater flow model is actualized in order to study the water table behavior in the zone of the Ojos Negros valley, which is located in the state of Baja California, Mexico. In the actualization process of the Ojos Negros valley's hydrogeological model, is used all the information proportionate for the National Commission of Water, as well as that information obtained from academic and research works achieved in the study zone, about the hydrogeological conditions that present the Ojos Negros and Real del Castillo aquifers. In addition, a groundwater flow simulator is modified and improved from the numerical point of view. The actualized simulator solves numerically the Boussinesq equation, using centrals finite-differences techniques, the "fully implicit" approximation for the temporary variation, and the iterative method of successive over relaxation. Also it counts with the structure to considering the temporary variation of the different variables and geohydrologics conditions that has influence upon the groundwater system, and with programming subroutines in MATLAB (2000) for the graphic display of results. The simulation results are appropriate for determining the phreatic surface and the flow directions in different time intervals. The phreatic surface information can be used for studying the behavior (temporary evolution) of water table in the aquifers.

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

    PubMed

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

    2015-11-01

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

  16. Delineating small karst watersheds based on digital elevation model and eco-hydrogeological principles

    NASA Astrophysics Data System (ADS)

    Jie Luo, Guang; Jie Wang, Shi; Bai, Xiao Yong; Liu, Xiu Ming; Cheng, An Yun

    2016-03-01

    Dominated by specific eco-hydrogeological backgrounds, a small watershed delineated by using the traditional method is always inauthentic in karst regions because it cannot accurately reflect the eco-hydrological process of the dual structure of the surface and subsurface. This study proposes a new method for the delineation of small watersheds based on digital elevation models (DEMs) and eco-hydrogeological principles in karst regions. This method is applied to one section of the tributary area (Sancha River) of the Yangtze River in China. By comparing the quantity, shape, superimposition, and characteristics of the internal hydrological process of a small watershed extracted by using the digital elevation model with that extracted by using the proposed method of this study, we conclude that the small karst watersheds extracted by the new method accurately reflect the hydrological process of the river basin. Furthermore, we propose that the minimum unit of the river basin in karst regions should be the watershed, whose exit is the corrosion and corrasion baselevel and a further division of watershed may cause a significant inconsistency with the true eco-hydrological process.

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

    USGS Publications Warehouse

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

    2000-01-01

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

  18. Hydrogeologic characterization of the cretaceous-tertiary Coastal Plain sequence at the Savannah River Site

    SciTech Connect

    Aadland, R.K.

    1990-01-01

    Several hydrostratigraphic classification schemes have been devised to describe the hydrogeology at the Savannah River Site SRS. Central to these schemes is the one-to-one fixed relationship between the hydrostratigraphic units and the lithostratigraphic units currently favored for the Site. This fixed relationship has proven difficult to apply in studies of widely separated locations at the Site due to the various facies observed in the updip Coastal Plain sequence. A detailed analysis and synthesis of the geophysical, core, and hydrologic data available from more than 164 deep wells from 23 cluster locations both on the Site and in the surrounding region was conducted to provide the basis for a hydrostratigraphic classification scheme which could be applied to the entire SRS region. As a result, an interim hydrostratigraphic classification was developed that defines the regional hydrogeologic characteristics of the aquifers underlying the Site (Aadland et al., 1990). The hydrostratigraphic code accounts for and accommodates the rapid lateral variation in lithofacies observed in the region, and eliminates all formal'' connection between the hydrostratigraphic nomenclature and the lithostratigraphic nomenclature. The code is robust and can be made as detailed as is needed to characterize the aquifer units and aquifer zones described in Site-specific studies. 15 refs., 2 figs.

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

    PubMed Central

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

    2013-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Krogulec, Ewa; Zabłocki, Sebastian

    2015-11-01

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

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

    USGS Publications Warehouse

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

    1984-01-01

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

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

    USGS Publications Warehouse

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

    2001-01-01

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

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

    USGS Publications Warehouse

    Papadopulos, Stavros Stefanu; Winograd, Isaac Judah

    1974-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2009-07-01

    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.

  7. The hydrogeology of the military inundation at the 1914-1918 Yser front (Belgium)

    NASA Astrophysics Data System (ADS)

    Vandenbohede, Alexander

    2015-12-01

    Protection against flooding by the sea, drainage of rainwater and integrated management of groundwater and surface-water resources are key issues in low-lying coastal areas. However, under exceptional circumstances, knowledge to keep coastal areas dry and habitable can be used otherwise. Inundation for military purposes is such an example. The hydrogeology of the inundation at the Yser River, Belgium, during the Great War is studied. The inundation started in October 1914 to stop the German advance and lasted until 1918. A water balance and groundwater model are combined to derive the water balance before and during the inundation and to study the impact on the groundwater system. It is concluded that a number of hydrogeological factors contributed to the effectiveness of the inundation. Most importantly, the low-permeability subsoil facilitated loss of inundation water mainly by evaporation. Further, the normal water management strategy of the area (aimed at evacuating excess water towards the sea) was reversed to keep water between the opposing armies. However, the duration of the inundation meant a reorganization of the drainage of areas not inundated; truly an exercise in integrated water management.

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

    NASA Astrophysics Data System (ADS)

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

    2009-09-01

    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.

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

    SciTech Connect

    1984-05-01

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

  10. The hydrogeology of the military inundation at the 1914-1918 Yser front (Belgium)

    NASA Astrophysics Data System (ADS)

    Vandenbohede, Alexander

    2016-03-01

    Protection against flooding by the sea, drainage of rainwater and integrated management of groundwater and surface-water resources are key issues in low-lying coastal areas. However, under exceptional circumstances, knowledge to keep coastal areas dry and habitable can be used otherwise. Inundation for military purposes is such an example. The hydrogeology of the inundation at the Yser River, Belgium, during the Great War is studied. The inundation started in October 1914 to stop the German advance and lasted until 1918. A water balance and groundwater model are combined to derive the water balance before and during the inundation and to study the impact on the groundwater system. It is concluded that a number of hydrogeological factors contributed to the effectiveness of the inundation. Most importantly, the low-permeability subsoil facilitated loss of inundation water mainly by evaporation. Further, the normal water management strategy of the area (aimed at evacuating excess water towards the sea) was reversed to keep water between the opposing armies. However, the duration of the inundation meant a reorganization of the drainage of areas not inundated; truly an exercise in integrated water management.

  11. GIS Approach for Preventive Evaluation of Roads Loss of Efficiency in Hydrogeological Emergencies

    NASA Astrophysics Data System (ADS)

    Mangiameli, M.; Mussumeci, G.

    2013-01-01

    The theme of the simulation of hydrogeological risk with GIS technology is analyzed with focus on the modeling of the architecture of a Spatial Data Base to support risk analysis and on the construction of a specialized frame with free and open source software. For this purpose a model of analysis of the vulnerability of roads developed by (Cafiso et al., 2002) has been adopted. The case of study is represented by a seismic land characterized by steep slopes and frequent instability phenomena. In detail, the area of interest is a mountainous land in Sicily with a city, Enna (about 30 000 people), that lies on the top. The access to the city is assured by few and very winding roads which are also highly vulnerable to seismic and hydrogeological hazards. The loss of efficiency of these roads for exceptional rainfall events should compromise timeliness and effectiveness of rescue operations. The data of the sample area have been implemented in the specialized GIS appositely constructed in order to forecast the possible damage to roads and the results of some simulations have been related to the effects registered after some extreme events, obtaining useful indications for the validation of the approach.

  12. Characteristics of Fracture Networks and Hydrogeologic Units: Implications Provided by Detailed Hydraulic Head Profiles

    NASA Astrophysics Data System (ADS)

    Meyer, J. R.; Parker, B. L.; Cherry, J. A.

    2009-05-01

    Plume characterization in fractured rock is particularly challenging because of the inherent complexity that is difficult to characterize using conventional data. This field study demonstrates how exceptionally detailed head profiles provide definition of the hydrogeologic framework for a sedimentary rock aquifer system impacted by an extensive mixed organic contaminant plume. The site is located in south central Wisconsin and overlies nearly flat lying fractured Paleozoic sandstones and dolostones. Many of these bedrock geologic units were deposited in a marine setting and as a result are laterally extensive across the cratonic interior of North America. Several regional groundwater flow models exist for south central Wisconsin. In the hydrogeologic framework for these models, the various bedrock units are lumped into a lower aquifer, an aquitard, and an upper aquifer. While this framework may be sufficient for regional groundwater flow models, historical data from the field site indicate it is not an appropriate framework for contaminant transport at the site scale. As a result, field studies were designed to collect detailed data from continuous core, geophysical and hydrophysical logging of the corehole, and detailed multilevel systems (MLSs) to define the hydrogeologic framework for the site. A preliminary study by Meyer et al. (2008) involved the installation of one very detailed MLS, 36 monitoring zones over 120.7 m, in the MP-6 corehole upgradient of the plume. The MP-6 hydraulic head profile is characterized by segments with minimal vertical hydraulic gradient separated by distinct inflections. Meyer et al. (2008) concluded that the sharp inflections observed in the MP-6 head profile delineated the positions of low vertical hydraulic conductivity interfaces which are not distinguishable based on stratigraphy, geophysics, or other conventional indirect indicators alone. The inflections in the head profile were interpreted as the contacts between hydrogeologic units (HGUs) and were used to delineate 11 HGUs at the MP-6 location. The sections of the head profile with minimal vertical gradient indicate an interconnected fracture network and a dominance of horizontal flow within each HGU. In the current study, seven additional detailed multilevel systems were installed across the site to investigate the lateral continuity of the hydraulic head inflections observed at MP-6. The head profiles measured from all eight MLSs have similar simple geometries: sections of minimal hydraulic gradient separated by sharp vertical inflections. The elevations of the hydraulic head inflections at each of the eight coreholes are strongly correlated despite separation distances of up to 3 km. The inflections observed in the detailed head profiles allow for the delineation of up to 13 bedrock HGUs at the site in contrast to the three bedrock HGUs commonly used in regional groundwater flow models. These 13 bedrock HGUs will provide the framework for site scale numerical modeling of groundwater flow and contaminant transport. The results of this study demonstrate that pre-existing regional stratigraphic frameworks are generally not an appropriate hydrogeologic framework, particularly in dual porosity/permeability systems where contaminant transport and fate is a concern. In addition, the simple geometry of the head profiles suggests an ordered and interconnected fracture network within each HGU and a poor vertical hydraulic connection between the fracture networks of adjacent HGUs.

  13. Hydrogeologic framework, groundwater movement, and water budget of the Kitsap Peninsula, west-central Washington

    USGS Publications Warehouse

    Welch, Wendy B.; Frans, Lonna M.; Olsen, Theresa D.

    2014-01-01

    This report presents information used to characterize the groundwater-flow system on the Kitsap Peninsula, and includes descriptions of the geology and hydrogeologic framework, groundwater recharge and discharge, groundwater levels and flow directions, seasonal groundwater-level fluctuations, interactions between aquifers and the surface‑water system, and a water budget. The Kitsap Peninsula is in the Puget Sound lowland of west-central Washington, is bounded by Puget Sound on the east and by Hood Canal on the west, and covers an area of about 575 square miles. The peninsula encompasses all of Kitsap County, the part of Mason County north of Hood Canal, and part of Pierce County west of Puget Sound. The peninsula is surrounded by saltwater and the hydrologic setting is similar to that of an island. The study area is underlain by a thick sequence of unconsolidated glacial and interglacial deposits that overlie sedimentary and volcanic bedrock units that crop out in the central part of the study area. Geologic units were grouped into 12 hydrogeologic units consisting of aquifers, confining units, and an underlying bedrock unit. A surficial hydrogeologic unit map was developed and used with well information from 2,116 drillers’ logs to construct 6 hydrogeologic sections and unit extent and thickness maps. Unconsolidated aquifers typically consist of moderately to well-sorted alluvial and glacial outwash deposits of sand, gravel, and cobbles, with minor lenses of silt and clay. These units often are discontinuous or isolated bodies and are of highly variable thickness. Unconfined conditions occur in areas where aquifer units are at land surface; however, much of the study area is mantled by glacial till, and confined aquifer conditions are common. Groundwater in the unconsolidated aquifers generally flows radially off the peninsula in the direction of Puget Sound and Hood Canal. These generalized flow patterns likely are complicated by the presence of low-permeability confining units that separate discontinuous bodies of aquifer material and act as local groundwater-flow barriers. Groundwater-level fluctuations observed during the monitoring period (2011–12) in wells completed in unconsolidated hydrogeologic units indicated seasonal variations ranging from 1 to about 20 feet. The largest fluctuation of 33 feet occurred in a well that was completed in the bedrock unit. Streamgage discharge measurements made during 2012 indicate that groundwater discharge to creeks in the area ranged from about 0.41 to 33.3 cubic feet per second. During 2012, which was an above-average year of precipitation, the groundwater system received an average of about 664,610 acre-feet of recharge from precipitation and 22,122 acre-feet of recharge from return flows. Most of this annual recharge (66 percent) discharged to streams, and only about 4 percent was withdrawn from wells. The remaining groundwater recharge (30 percent) left the groundwater system as discharge to Hood Canal and Puget Sound.

  14. Extraterrestrial hydrogeology

    NASA Astrophysics Data System (ADS)

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

    2005-03-01

    Subsurface water processes are common for planetary bodies in the solar system and are highly probable for exoplanets (planets outside the solar system). For many solar system objects, the subsurface water exists as ice. For Earth and Mars, subsurface saturated zones have occurred throughout their planetary histories. Earth is mostly clement with the recharge of most groundwater reservoirs from ample precipitation during transient ice- and hot-house conditions, as recorded through the geologic and fossilized records. On the other hand, Mars is mostly in an ice-house stage, which is interrupted by endogenic-driven activity. This activity catastrophically drives short-lived hydrological cycling and associated climatic perturbations. Regional aquifers in the Martian highlands that developed during past, more Earth-like conditions delivered water to the northern plains. Water was also cycled to the South Polar Region during changes in climate induced by endogenic activity and/or by changes in Mars' orbital parameters. Venus very likely had a warm hydrosphere for hundreds of millions of years, before the development of its current extremely hot atmosphere and surface. Subsequently, Venus lost its hydrosphere as solar luminosity increased and a run-away moist greenhouse took effect. Subsurface oceans of water or ammonia-water composition, induced by tidal forces and radiogenic heating, probably occur on the larger satellites Europa, Ganymede, Callisto, Titan, and Triton. Tidal forces operating between some of the small bodies of the outer solar system could also promote the fusion of ice and the stability of inner liquid-water oceans. Les processus de subsurface impliquant l'eau sont communs pour les corps planétaires du système solaire et sont très probables sur les exoplanètes (planètes en dehors du système solaire). Pour plusieurs objets du systèmes solaire, l'eau de subsurface est présente sous forme de glace. Pour la Terre et Mars, les zones saturées de subsurface apparaissent à travers toute leur histoire planétaire. La Terre est particulièrement clémente avec la recharge des réservoirs, avec de amples précipitations, des conditions glaciaires et de fortes chaleurs, comme l'atteste les enregistrements géologiques et paléontologiques. D'un autre côté, Mars se trouve dans une phase essentiellement glaciaire, qui est interrompue par des activités contraintes par les phénomènes endogéniques. Cette activité conduit de manière catastrophique à des cycles hydrologiques et à des perturbations climatiques brutaux. Les aquifères régionaux dans les haute terres martiennes qui se sont formés dans des conditions similaires aux conditions terrestres, alimentent les plaines du Nord. L'eau a également été déplacée vers le Pôle Sud martien durant des changements marqués par une forte activité endogénique et une modification des paramètres de l'orbite de Mars. Venus possèdait vrais emblablement une hydrosphère chaude durant des millions d'année, avant le développement de son atmosphère et sa surface particulièrement chaude. Par après Venus a perdit son hydrosphère alors que la luminosité solaire augmentait et qu'une humidité liée à un effet de serre s'installait. Les océans de subsurface d'eau ou d'eau ammoniacale, induits par les forces de marée et le chauffage radiogénique, apparaissent probablement sur les satellites les plus importants (Europa, Ganymede, Callisto, Titan, Triton). Les forces de marée entre les petits corps externes du système solaire peuvent également occasionner la fusion de glace et la stabilité des océans internes d'eau liquide. Los procesos hídricos subsuperficiales son comunes en cuerpos planetarios del sistema solar y son altamente probables para exoplanetas (planetas fuera del sistema solar). Para muchos cuerpos del sistema solar, el agua subsuperficial existe como hielo. Para la Tierra y Marte han ocurrido zonas saturadas subsuperficiales a través de sus historias planetarias. La Tierra es principalmente generosa con la recarga de la mayoría de reservorios de aguas subterráneas a partir de amplia precipitación reconocida en condiciones transitorias calientes y heladas, tal y como aparece en los registros fósiles y geológicos. Por otro lado, Marte se encuentra principalmente en una etapade cámara de hielo la cual es interrumpida por actividad de tipo endogénico. Esta actividad pone en funcionamiento catastróficamente ciclos hidrológicos de vida corta y perturbaciones climáticas asociadas. Acuíferos regionales en las montañas de Marte que se desarrollaron en el pasado en condiciones similares a la Tierra distribuyen agua a las planicies del norte. El agua ha sido transportada hacia el sur de la región polar durante cambios en el clima inducidos por actividad endogénica y/o cambios en los parámetros orbitales de Marte. Venus muy probablemente tuvo una hidrósfera caliente durante cientos de millones de años, antes de que se desarrollara su atmósfera y superficie actual extremadamente caliente. Subsecuentemente, Venus perdió su hidrósfera a medida que la luminosidad solar aumentó y un efecto de invernadero húmedo escapatorio se llevó a cabo. Océanos subsuperficiales de composición agua o amoniaco-agua, inducidos por fuerzas de marea y calentamiento radiogénico, probablemente ocurren en los satélites más grandes como Europa, Ganimeda, Callisto, Titan y Triton. Las fuerzas de marea que operan entre los cuerpos pequeños del sistema solar externo podrían también promover la fusión de hielo y la estabilidad de líquido interno-aguas de los océanos.

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

    SciTech Connect

    1996-02-01

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

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

    USGS Publications Warehouse

    Banta, Edward R.; Provost, Alden M.

    2008-01-01

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

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

    USGS Publications Warehouse

    Shah, Sachin D.; Houston, Natalie A.

    2007-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2007-12-01

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

  19. Geochemical and hydrogeologic evolution of alkaline discharges from abandoned coal mines

    SciTech Connect

    Winters, W.R.; Capo, R.C.; Wolinsky, M.A.; Weaver, T.J.; Hedin, R.S.

    1999-07-01

    Numerous large flow (> 2,000 l/min), historically (pre-1973) acidic, abandoned underground deep mine discharges in southwestern Pennsylvania are now alkaline in character, with circumneutral pH. Recently measured flow rates are consistent with those measured 25--30 years ago; thus the change in chemistry is not simply due to dilution by increased flows of uncontaminated water through the mines. It is likely that flooding of the mines has decreased the extent of acidity enhancing aerobic conditions, and that decades of weathering have reduced the amount of reactive pyrite. However, the mines continue to yield a sulfate-rich, Fe-contaminated (19--79 ppm) drainage. These highly alkaline discharges (up to 330 ppm as CaCO{sub 3}) are accompanied by large concentrations of sodium (up to 700 ppm) and suggest cation exchange with the associated overburden. To assess the hydrogeological conditions that result in the formation of alkaline Fe-contaminated mine discharges, the authors examined all the major discharges from a single synclinal basin. The northeast-trending Irwin synclinal coal basin encompasses 94 mi{sup 2} and was extensively mined by underground methods during the first half of this century. All major streams that arise within or cross the syncline are polluted by mine drainage that ranges from highly acidic Fe- and Al-contaminated discharges in the northern portion of the syncline to highly alkaline, iron and sulfate-contaminated discharges to the south. The hydrology of the basin is controlled by its southern plunging structure, by outcrops or drainage tunnels on the western arms of the syncline, and by several coal barriers. A first-order hydrogeologic model was constructed to evaluate ground water flow into and through the mine complexes found in the basin. The model integrates the basin geometry with structural and mine barrier components to determine groundwater flow paths and estimate residence time. Water quality is related to the cumulative proportion of up-gradient flooded and unflooded mine workings. Small discharges from unflooded, gravity-flow portions of the mined-out portion of the Pittsburgh Coal seam are highly acidic, and large artesian flows of water affected by only a short flow through flooded anoxic mine pools are moderately acidic. Those discharges subjected to increased residence time in flooded anoxic portions of the mines are increasingly alkaline. Refinement of this model could aid in prediction and hydrogeologic manipulation of these high flow Fe-contaminated discharges that are the main pollutant in many streams throughout Northern Appalachia and other coal mining areas throughout the world.

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

    NASA Astrophysics Data System (ADS)

    Bauer, Helene; Decker, Kurt

    2014-05-01

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

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

    NASA Astrophysics Data System (ADS)

    Alhamed, Mohammad

    2014-11-01

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

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

    NASA Astrophysics Data System (ADS)

    Andreo, B.

    2013-12-01

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

  3. Hydrogeologic framework and groundwater/surface-water interactions of the Chehalis River basin, Washington

    USGS Publications Warehouse

    Gendaszek, Andrew S.

    2011-01-01

    The Chehalis River has the largest drainage basin of any river entirely contained within the State of Washington with a watershed of approximately 2,700 mi2 and has correspondingly diverse geology and land use. Demands for water resources have prompted the local citizens and governments of the Chehalis River basin to coordinate with Federal, State and Tribal agencies through the Chehalis Basin Partnership to develop a long-term watershed management plan. The recognition of the interdependence of groundwater and surface-water resources of the Chehalis River basin became the impetus for this study, the purpose of which is to describe the hydrogeologic framework and groundwater/surface-water interactions of the Chehalis River basin. Surficial geologic maps and 372 drillers' lithostratigraphic logs were used to generalize the basin-wide hydrogeologic framework. Five hydrogeologic units that include aquifers within unconsolidated glacial and alluvial sediments separated by discontinuous confining units were identified. These five units are bounded by a low permeability unit comprised of Tertiary bedrock. A water table map, and generalized groundwater-flow directions in the surficial aquifers, were delineated from water levels measured in wells between July and September 2009. Groundwater generally follows landsurface-topography from the uplands to the alluvial valley of the Chehalis River. Groundwater gradients are highest in tributary valleys such as the Newaukum River valley (approximately 23 cubic feet per mile), relatively flat in the central Chehalis River valley (approximately 6 cubic feet per mile), and become tidally influenced near the outlet of the Chehalis River to Grays Harbor. The dynamic interaction between groundwater and surface-water was observed through the synoptic streamflow measurements, termed a seepage run, made during August 2010, and monitoring of water levels in wells during the 2010 Water Year. The seepage run revealed an overall gain of 56.8 ± 23.7 cubic feet per second over 32.8 river miles (1.7 cubic feet per second per mile), and alternating gains and losses of streamflow ranging from -48.3 to 30.9 cubic feet per second per mile, which became more pronounced on the Chehalis River downstream of Grand Mound. However, most gains and losses were within measurement error. Groundwater levels measured in wells in unconsolidated sediments fluctuated with changes in stream stage, often within several hours. These fluctuations were set by precipitation events in the upper Chehalis River basin and tides of the Pacific Ocean in the lower Chehalis River basin.±

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

    NASA Astrophysics Data System (ADS)

    Roggenthen, B.

    2013-12-01

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

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

    USGS Publications Warehouse

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

    1996-01-01

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

  6. Integrating advanced 3D Mapping into Improved Hydrogeologic Frameworks, a Future path for Groundwater Modeling? Results from Western Nebraska

    NASA Astrophysics Data System (ADS)

    Cannia, J. C.; Abraham, J. D.; Peterson, S. M.; Sibray, S. S.

    2012-12-01

    The U.S. Geological Survey and its partners have collaborated to provide an innovative, advanced 3 dimensional hydrogeologic framework which was used in a groundwater model designed to test water management scenarios. Principal aquifers for the area mostly consist of Quaternary alluvium and Tertiary-age fluvial sediments which are heavily used for irrigation, municipal and environmental uses. This strategy used airborne electromagnetic (AEM) surveys, validated through sensitivity analysis of geophysical and geological ground truth to provide new geologic interpretation to characterize the hydrogeologic framework in the area. The base of aquifer created through this work leads to new interpretations of saturated thickness and groundwater connectivity to the surface water system. The current version of the groundwater model which uses the advanced hydrogeologic framework shows a distinct change in flow path orientation, timing and amount of base flow to the streams of the area. Ongoing efforts for development of the hydrogeologic framework development include subdivision of the aquifers into new hydrostratigraphic units based on analysis of geophysical and lithologic characteristics which will be incorporated into future groundwater models. The hydrostratigraphic units are further enhanced by Nuclear Magnetic Resonance (NMR) measurements to characterize aquifers. NMR measures the free water in the aquifer in situ allowing for a determination of hydraulic conductivity. NMR hydraulic conductivity values will be mapped to the hydrostratigraphic units, which in turn are incorporated into the latest versions of the groundwater model. The addition of innovative, advanced 3 dimensional hydrogeologic frameworks, which incorporates AEM and NMR, for groundwater modeling, has a definite advantage over traditional frameworks. These groundwater models represent the natural system at a level of reality not achievable by other methods, which lead to greater confidence in the management decisions for the resource.

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

    USGS Publications Warehouse

    Kidd, Robert E.

    2001-01-01

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

  8. Hydrogeologic and geochemical precursors of earthquakes: an assessment for possible applications

    NASA Astrophysics Data System (ADS)

    Martinelli, G.

    2015-06-01

    Groundwaters and gaseous emissions have been analyzed in the past with the purpose to contribute to earthquake prediction researches. Main test sites were Japan, U.S.A., former U.S.S.R., China and Turkey. Catalogues of presumed precursory episodes have been compiled over the years and allowed to reach preliminary conclusions about site selection techniques. Controlled experimental sites have recently given the opportunity to better investigate the physical mechanisms originating recorded pre-seismic anomalies. Main characteristics and limitations of hydrogeologic and geochemical parameters are discussed. An in-depth review of results obtained in most relevant test site areas allow to project future instrumental networks oriented to hazard reduction policies

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

    USGS Publications Warehouse

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

    2014-01-01

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

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

    USGS Publications Warehouse

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

    2009-01-01

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

  11. Selected Hydrogeologic Data for the High Plains Aquifer in Southwestern Laramie County, Wyoming, 1931-2006

    USGS Publications Warehouse

    Hallberg, Laura L.; Mason, Jon P.

    2007-01-01

    The U.S. Geological Survey, in cooperation with the Wyoming State Engineer's Office, created a hydrogeologic database for southwestern Laramie County, Wyoming. The database contains records from 166 wells and test holes drilled during 1931-2006. Several types of information, including well construction; well or test hole locations; lithologic logs; gamma, neutron, spontaneous-potential, and single-point resistivity logs; water levels; and transmissivities and storativities estimated from aquifer tests, are available in the database. Most wells and test holes in the database have records containing information about construction, location, and lithology; 77 wells and test holes have geophysical logs; 70 wells have tabulated water-level data; and 60 wells have records of aquifer-test results.

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

    USGS Publications Warehouse

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

    1999-01-01

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

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

    SciTech Connect

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

    2011-05-05

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

  14. Index-based groundwater vulnerability mapping models using hydrogeological settings: A critical evaluation

    SciTech Connect

    Kumar, Prashant; Bansod, Baban K.S.; Debnath, Sanjit K.; Thakur, Praveen Kumar; Ghanshyam, C.

    2015-02-15

    Groundwater vulnerability maps are useful for decision making in land use planning and water resource management. This paper reviews the various groundwater vulnerability assessment models developed across the world. Each model has been evaluated in terms of its pros and cons and the environmental conditions of its application. The paper further discusses the validation techniques used for the generated vulnerability maps by various models. Implicit challenges associated with the development of the groundwater vulnerability assessment models have also been identified with scientific considerations to the parameter relations and their selections. - Highlights: • Various index-based groundwater vulnerability assessment models have been discussed. • A comparative analysis of the models and its applicability in different hydrogeological settings has been discussed. • Research problems of underlying vulnerability assessment models are also reported in this review paper.

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

    USGS Publications Warehouse

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

    2012-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Aceto, L.; Petrucci, O.

    2014-09-01

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

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

    SciTech Connect

    Not Available

    1991-01-01

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

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

    USGS Publications Warehouse

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

    2003-01-01

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

  19. Hydrogeology of the Helena Valley-fill aquifer system, west-central Montana. Water resources investigation

    SciTech Connect

    Briar, D.W.; Madison, J.P.

    1992-01-01

    The report, which presents the study results, describes the hydrogeology of the valley-fill aquifer system. Specific objectives were to: describe the geometry and the hydraulic characteristics of the aquifer system; define the potentiometric surface and the direction of ground-water flow; locate and quantify sources of ground-water recharge and discharge including surface- and ground-water interactions; and characterize the water quality in terms of susceptibility of the aquifer system to contamination and in terms of concentrations, distribution, and sources of major ions, trace elements, and organic compounds. The results of the study will be useful to the development of a comprehensive management program for the use and protection of the ground-water resources of the Helena Valley.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

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

    USGS Publications Warehouse

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

    1978-01-01

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

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

    USGS Publications Warehouse

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

    2001-01-01

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

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

    USGS Publications Warehouse

    Tenbus, Frederick J.; Blomquist, Joel D.

    1995-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Boisvert, E.; Brodaric, B.

    2008-12-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

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

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

    NASA Astrophysics Data System (ADS)

    Legrand, Harry E.

    1989-05-01

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

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

    PubMed

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

    2013-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

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

    PubMed

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

    2015-01-01

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

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

    SciTech Connect

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

    2015-01-01

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

  11. Hydrogeology and tritium transport in Chicken Creek Canyon,Lawrence Berkeley National Laboratory, Berkeley, California

    SciTech Connect

    Jordan, Preston D.; Javandel, Iraj

    2007-10-31

    This study of the hydrogeology of Chicken Creek Canyon wasconducted by the Environmental Restoration Program (ERP) at LawrenceBerkeley National Laboratory (LBNL). This canyon extends downhill fromBuilding 31 at LBNL to Centennial Road below. The leading edge of agroundwater tritium plume at LBNL is located at the top of the canyon.Tritium activities measured in this portion of the plume during thisstudy were approximately 3,000 picocuries/liter (pCi/L), which issignificantly less than the maximum contaminant level (MCL) for drinkingwaterof 20,000 pCi/L established by the Environmental ProtectionAgency.There are three main pathways for tritium migration beyond theLaboratory s boundary: air, surface water and groundwater flow. Thepurpose of this report is to evaluate the groundwater pathway.Hydrogeologic investigation commenced with review of historicalgeotechnical reports including 35 bore logs and 27 test pit/trench logsas well as existing ERP information from 9 bore logs. This was followedby field mapping of bedrock outcrops along Chicken Creek as well asbedrock exposures in road cuts on the north and east walls of the canyon.Water levels and tritium activities from 6 wells were also considered.Electrical-resistivity profiles and cone penetration test (CPT) data werecollected to investigate the extent of an interpreted alluvial sandencountered in one of the wells drilled in this area. Subsequent loggingof 7 additional borings indicated that this sand was actually anunusually well-sorted and typically deeply weathered sandstone of theOrinda Formation. Wells were installed in 6 of the new borings to allowwater level measurement and analysis of groundwater tritium activity. Aslug test and pumping tests were also performed in the wellfield.

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

    SciTech Connect

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

    1992-01-01

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

  13. Gravimetry contributions to the study of the complex western Haouz aquifer (Morocco): Structural and hydrogeological implications

    NASA Astrophysics Data System (ADS)

    Chouikri, Ibtissam; el Mandour, Abdennabi; Jaffal, Mohammed; Baudron, Paul; García-Aróstegui, José-Luis; Manar, Ahmed; Casas, Albert

    2016-03-01

    This study provides new elements that illustrate the benefits of combining gravity, structural, stratigraphic and piezometric data for hydrogeological purposes. A combined methodology was applied to the western Haouz aquifer (Morocco), one of the main sources of water for irrigation and human consumption in the Marrakech region. First, a residual anomaly map was calculated from the Bouguer anomaly data. The computed map provided information on the ground density variation, revealing a strong control by a regional gradient. We then used various filtering techniques to delineate the major geological structures such as faults and basins: vertical and horizontal derivatives and upward continuation. This technique highlighted news structures and provided information on their dip. The gravity anomalies perfectly delineated the basement uplifts and the sedimentary thickening in depressions and grabens. The interpretation of gravimetric filtering, geological and hydrogeological data then highlighted two types of groundwater reservoirs, an unconfined aquifer hosted in conglomeratic mio-pliocene and quaternary rocks, covering the entire western Haouz and a deep confined aquifer contained in cenomanian-turonian limestone and eocene dolomitic formations in the south. Combining piezometric and residual anomaly maps revealed that groundwater flow and storage was in perfect agreement with the structures showing a negative anomaly, while structures with positive anomalies corresponded to groundwater divides. The study of gravity gradient zones by contact analysis enhanced the existing structural pattern of the study area and highlighted new structures, mainly oriented N70 and N130. The results of this study present a common framework and provide a notable step forward in the knowledge of the geometry and the groundwater flow pattern of the western Haouz aquifer, and will serve as a solid basis for a better water resource management.

  14. Effects of hydrogeological properties on sea-derived benzene transport in unconfined coastal aquifers.

    PubMed

    Li, Wei-Ci; Ni, Chuen-Fa; Tsai, Chia-Hsing; Wei, Yi-Ming

    2016-05-01

    This paper presents numerical investigations on quantifying the hydrodynamic effects of coastal environment factors, including tidal fluctuations, beach slopes, hydraulic conductivity, and hydraulic gradients on sea-derived benzene transport in unconfined coastal aquifers. A hydrologic transport and mixed geochemical kinetic/equilibrium reactions in saturated-unsaturated media model was used to simulate the spatial and temporal behaviors of the density flow and benzene transport for various hydrogeological conditions. Simulation results indicated that the tidal fluctuations lead to upper saline plumes (USPs) near the groundwater and seawater interfaces. Such local circulation zones trapped the seaward benzene plumes and carried them down in aquifers to the depth depending on the tide amplitudes and beach slopes across the coastal lines. Comparisons based on different tidal fluctuations, beach slopes, hydraulic conductivity, and hydraulic gradient were systematically conducted and quantified. The results indicated that areas with USPs increased with the tidal amplitude and decreased with the increasing beach slope. However, the variation of hydraulic conductivity and hydraulic gradient has relatively small influence on the patterns of flow fields in the study. The increase of the USP depths was linearly correlated with the increase of the tidal amplitudes. The benzene reactive transport simulations revealed that the plume migrations are mainly controlled by the local flow dynamics and constrained in the USP circulation zones. The self-cleaning process of a coastal aquifer is time-consuming, typically requiring double the time of the contamination process that the benzene plume reach the bottom of a USP circulation zone. The presented systematic analysis can provide useful information for rapidly evaluating seaward contaminants along a coastal line with available hydrogeological properties. PMID:27106208

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

    NASA Astrophysics Data System (ADS)

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

    2009-04-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  17. Digital surfaces and thicknesses of selected hydrogeologic units of the Floridan aquifer system in Florida and parts of Georgia, Alabama, and South Carolina

    USGS Publications Warehouse

    Williams, Lester J.; Dixon, Joann F.

    2015-01-01

    Digital surfaces and thicknesses of selected hydrogeologic units of the Floridan aquifer system were developed to define an updated hydrogeologic framework as part of the U.S. Geological Survey Groundwater Resources Program. The dataset contains structural surfaces depicting the top and base of the aquifer system, its major and minor hydrogeologic units and zones, geophysical marker horizons, and the altitude of the 10,000-milligram-per-liter total dissolved solids boundary that defines the approximate fresh and saline parts of the aquifer system. The thicknesses of selected major and minor units or zones were determined by interpolating points of known thickness or from raster surface subtraction of the structural surfaces. Additional data contained include clipping polygons; regional polygon features that represent geologic or hydrogeologic aspects of the aquifers and the minor units or zones; data points used in the interpolation; and polygon and line features that represent faults, boundaries, and other features in the aquifer system.

  18. Arsenic in groundwater of Licking County, Ohio, 2012—Occurrence and relation to hydrogeology

    USGS Publications Warehouse

    Thomas, Mary Ann

    2016-01-01

    Arsenic concentrations were measured in samples from 168 domestic wells in Licking County, Ohio, to document arsenic concentrations in a wide variety of wells and to identify hydrogeologic factors associated with arsenic concentrations in groundwater. Elevated concentrations of arsenic (greater than 10.0 micrograms per liter [µg/L]) were detected in 12 percent of the wells (about 1 in 8). The maximum arsenic concentration of about 44 µg/L was detected in two wells in the same township.A subset of 102 wells was also sampled for iron, sulfate, manganese, and nitrate, which were used to estimate redox conditions of the groundwater. Elevated arsenic concentrations were detected only in strongly reducing groundwater. Almost 20 percent of the samples with iron concentrations high enough to produce iron staining (greater than 300 µg/L) also had elevated concentrations of arsenic.In groundwater, arsenic primarily occurs as two inorganic species—arsenite and arsenate. Arsenic speciation was determined for a subset of nine samples, and arsenite was the predominant species. Of the two species, arsenite is more difficult to remove from water, and is generally considered to be more toxic to humans.Aquifer and well-construction characteristics were compiled from 99 well logs. Elevated concentrations of arsenic (and iron) were detected in glacial and bedrock aquifers but were more prevalent in glacial aquifers. The reason may be that the glacial deposits typically contain more organic carbon than the Paleozoic bedrock. Organic carbon plays a role in the redox reactions that cause arsenic (and iron) to be released from the aquifer matrix. Arsenic concentrations were not significantly different for different types of bedrock (sandstone, shale, sandstone/shale, or other). However, arsenic concentrations in bedrock wells were correlated with two well-construction characteristics; higher arsenic concentrations in bedrock wells were associated with (1) shorter open intervals and (2) deeper open intervals, relative to the water level.The spatial distribution of arsenic concentrations was compared to hydrogeologic characteristics of Licking County. Elevated concentrations of arsenic (and iron) were associated with areas of flat topography and thick (greater than 100 feet),clay-rich glacial deposits. These characteristics are conducive to development of strongly reducing redox conditions, which can cause arsenic associated with iron oxyhydroxides in the aquifer matrix to be released to the groundwater.Hydrogeologic characteristics conducive to the development of strongly reducing groundwater are relatively wide-spread in the western part of Licking County, which is part of the Central Lowland physiographic province. In this area, a thick layer of clay-rich glacial deposits obscures the bedrock surface and creates flat to gently rolling landscape with poorly developed drainage networks. In the eastern part of the county, which is part of the Appalachian Plateaus physiographic province, the landscape includes steep-sided valleys and bedrock uplands. In this area, elevated arsenic concentrations were detected in buried valleys but not in the bedrock uplands, where glacial deposits are thin or absent. The observation that elevated concentrations of arsenic (and iron) were more prevalent in the western part of Licking County is true for both glacial and bedrock aquifers.In Licking County, thick, clay-rich glacial deposits (and elevated concentrations of arsenic) are associated with two hydrogeologic settings—buried valley and complex thick drift. Most wells in the buried-valley setting had low arsenic concentrations, but a few samples had very high concentrations (30–44 µg/L) and very reducing redox conditions (methanogenic and near-methanogenic). For wells in the complex-thick-drift setting, elevated arsenic concentrations are more prevalent, but the maximum concentration was lower (about 21 µg/L). Similar observations were made about arsenic concentrations in parts of southwestern Ohio.The hydrogeologic settings and characteristics associated with arsenic in Licking County also exist in other parts of Ohio. The statewide extent of these characteristics roughly corresponds to areas where elevated concentrations of arsenic are known to exist. This preliminary conceptual model can be tested and revised as additional wells are sampled for arsenic.

  19. Interest of hydrogeological study in the interpretation of pollen proxies for palaeo-climate reconstitution: example from Senegalese niayes

    NASA Astrophysics Data System (ADS)

    Maugis, P.; Aguiar, L.; Grenier, C.

    2009-04-01

    The Niayes of Senegal are interdunal fens, allowing propitious conditions to agriculture, despite a sahelian climate, thanks to the availability of fresh groundwater, coast proximity and distant recharge from a well rain-fed elevation. An azonal humid gallery forest settled 10000 years ago, and thrived throughout Holocene despite contrasted climatic conditions. Exploratory modelling of the zonal hydrogeology has been conducted for different periods with Cast3M code. The progressive onset of humid vegetation required both the high pluviometry of the African Humid Period, and shallowing groundwaters under sea-level rise. Vegetation degradation at 7500 cal BP resulted from climate minoration, possibly worsening until 4000 cal BP. The watertable allowed the degraded forest to persist during that period. Thus pollens, as water-availability proxies, yield the combined signatures of atmospheric hydrology, and hydrogeology.

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

    USGS Publications Warehouse

    Levings, J.F.

    1985-01-01

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

  1. Hydrogeologic framework and geologic structure of the Floridan aquifer system and intermediate confining unit in the Lake Okeechobee area, Florida

    USGS Publications Warehouse

    Reese, Ronald S.

    2014-01-01

    The successful implementation of aquifer storage and recovery (ASR) as a water-management tool requires detailed information on the hydrologic and hydraulic properties of the potential water storage zones. This report presents stratigraphic and hydrogeologic sections of the upper part of the Floridan aquifer system and the overlying confining unit or aquifer system in the Lake Okeechobee area, and contour maps of the upper contacts of the Ocala Limestone and the Arcadia Formation, which are represented in the sections. The sections and maps illustrate hydrogeologic factors such as confinement of potential storage zones, the distribution of permeability within the zones, and geologic features that may control the efficiency of injection, storage, and recovery of water, and thus may influence decisions on ASR activities in areas of interest to the Comprehensive Everglades Restoration Plan.

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

    USGS Publications Warehouse

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

    2002-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2009-04-01

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

  4. The Supporting Role of Mesocosm-Scale Laboratory Experiments in Solving Critical Issues at Hydrogeological Research Sites

    NASA Astrophysics Data System (ADS)

    Schincariol, R.; Nagare, R.; Quinton, W.; Hayashi, M.

    2008-12-01

    Hydrogeological research sites provide a unique opportunity to study parameters and processes at the field scale. However, the most successful long-term research sites have been coupled with laboratory-scale experiments and numerical modeling studies. Mesocosm-scale laboratory experiments allow the investigation of local-scale hydrogeological processes often with sensors that exceed the spatial, temporal, and accuracy of field based monitoring. After over two years of design and construction a unique mesocosm-scale hydrogeological climate chamber was emplaced at the University of Western Ontario Biotron facility in April 2008. What makes this chamber different from other ecohydrological chambers is the ability to reproduce the subarctic solar and atmospheric environment and house soil monoliths up to 1.5 m in diameter and 4 m in height. Of particular importance is the ability to subject soil monoliths, inclusive of vegetation, to climate forcing experiments (varying solar energy, air temperature, precipitation, wind, CO2) while continuously monitoring liquid, gas, and energy fluxes. At present, experiments on 60 cm diameter by 90 cm deep peat / permafrost cores from our central Mackenzie River basin long-term field site are being conducted to better elucidate moisture and carbon transport processes occurring in the active layer. These climate forcing laboratory based experiments will be closely integrated with on-going field studies in the basin. Through this research we will be able to develop a physically-based numerical model to estimate the volume and timing of runoff from wetland-dominated basins in discontinuous permafrost. The experiments will answer critical questions, not addressable by field data alone, on how subarctic ecosystems will respond to climate change. We would also like to foster collaborations to address other scientific questions utilizing the climate chamber. In particular, experiments in support of pilot scale remediation efforts in cold regions or phytoremediation studies would be ideally suited to this unique hydrogeological research facility.

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

    SciTech Connect

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

    1997-09-01

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

  6. Hydrogeologic framework, groundwater movement, and water budget in the Chimacum Creek basin and vicinity, Jefferson County, Washington

    USGS Publications Warehouse

    Jones, Joseph L.; Welch, Wendy B.; Frans, Lonna M.; Olsen, Theresa D.

    2011-01-01

    This report presents information used to characterize the groundwater flow system in the Chimacum Creek basin. It includes descriptions of the geology and hydrogeologic framework; groundwater recharge and discharge; groundwater levels and flow directions; seasonal fluctuations in groundwater level; interactions between aquifers and the surface-water system; and a groundwater budget. The study area covers 124 square miles in northeastern Jefferson County, Washington, and includes the Chimacum Creek basin, which drains an area of about 37 square miles. The area is underlain by a north-thickening sequence of unconsolidated glacial and interglacial deposits that overlie sedimentary and igneous bedrock units that crop out along the margins and western interior of the study area. Six hydrogeologic units consisting of unconsolidated aquifers and confining units, along with an underlying bedrock unit, were identified. A surficial hydrogeologic map was developed and used with well information from 187 drillers' logs to construct 4 hydrogeologic sections, and maps showing the extent and thickness of the units. Natural recharge was estimated using precipitation-recharge relation regression equations developed for western Washington, and estimates were calculated for return flow from data on domestic indoor and outdoor use and irrigated agriculture. Results from synoptic streamflow measurements and water table elevations determined from monthly measurements at monitoring wells are presented and compared with those from a study conducted during 2002-03. A water budget was calculated comprising long-term average recharge, domestic public-supply withdrawals and return flow, self-supplied domestic withdrawals and return flow, and irrigated agricultural withdrawals and return flow.

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

    SciTech Connect

    1995-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  9. Hydrogeological characterization of a potential CO2 injection site in Ottawa County, Michigan

    NASA Astrophysics Data System (ADS)

    Deng, H.; Peters, C. A.; Fitts, J. P.; Pollak, M.; Wilson, E.

    2010-12-01

    This work sought to characterize the hydrogeology of the sedimentary formations underlying Ottawa Count, Michigan, a potential injection site for geologic carbon sequestration in the Mt. Simon Sandstone (Cambrian). A hydrogeological model with comprehensive characterization of uncertainties is needed to predict the behavior of CO2 and the risk of leakage. To start, ArcGIS was used to construct a 3-D model of the subsurface using formation depth and thickness information determined from well data provided by the Department of Natural Resources and Environment (DNRE) of the State of Michigan. A total of 3449 wells, with depths ranging from 25 m to 2500 m, were included. Among them, 1048 are located in Ottawa County, while the others are in the neighboring counties of Muskegon, Kent and Allegan. Geophysical well logs were used to infer porosities. The results show that sandstones have higher porosity values, around 10%, whereas shales and well-cemented carbonates exhibit a large range, from less than one percent to as large as 40%, which indicates the presence of fractures. One objective of this work was to estimate formation permeabilities using the derived porosity data. Characterization of the highly consolidated layers such as shales and carbonates is particularly important in the context of geologic carbon sequestration because of the need to determine their integrity as CO2-trapping caprocks. For these layers, accurate estimation of permeability from well-log porosity is complicated because of the fractured nature of these rocks. Existing porosity-permeability relationships are empirical and based on granular matrices. As a result, these relationships are not able to represent the influences of clay content on permeability and the permeability caused by fractures. Accurate estimation of permeability in fractured media requires knowledge of fracture geometry, density, and spatial distribution. For microfractures, as may occur from microseismicity, this information is typically not obtained from well-logging instruments. The current study seeks to quantify the range of permeabilities that is possible in a consolidated rock with a given porosity. Treating the rock as continuous porous media and applying the Kozeny-Carman porosity-permeability relationship gives the lower bound; while the upper bound was estimated by assuming an impermeable matrix and a simplified fracture network.

  10. Efficiency Evaluation of Open-Loop GHPS Operation Under Various Hydrogeological Conditions

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

    Geothermal heat pump system (GHPS) can be cost-effective renewable energy sources. In order to develop the GHPS which has certain hydrogeological characteristics, understanding the thermohydraulic process of an aquifer is necessary for effective usage of open-loop GHPS. Experimental and numerical tests are performed for two concepts of open-loop GHPS: simple open-loop and energy storage concept. In simple open-loop sets, tests were performed fixing the locations of pumping and injection wells. In contrast, tests in energy storage sets were conducted by changing the locations of wells in a seasonal cycle. Experimental test using sand tank was performed only for the simple open-loop concept, while numerical tests were performed for the both concepts. Numerical modeling results using FEFLOW were compatible with the experimental results. In the simple open-loop sets, the temporal temperature change in a pumping well was measured. Effective operation conditions are obtained with high hydraulic conductivity (3X10-3 m/s) and long distance (60 cm) between wells on hydraulic gradient 0.025 because the effect of injected water temperature must be minimized. In the energy storage sets, thermal recovery factors (R) under various conditions were calculated to evaluate the efficiency. Low hydraulic conductivity (3X10-5 m/s), hydraulic gradient 0.0 and long well distance (more than 20 m) are the best conditions for operation efficiency (R=37.92) because faster groundwater flow lead to advection or down-gradient `drift' of stored energy beyond potential recovery regions. In the case of two-layered aquifer, the porosity and groundwater flow characteristics of each layer sensitively affected the migration of thermal plume. Two-layered aquifer with the top-layer of low hydraulic conductivity (3X10-5 m/s) and porosity (0.2) is profitable for the effective open-loop GHPS operation under hydraulic gradient 0.0 and well distance (20 m). The results from experimental and numerical tests can provide a helpful guideline for effective usage and design of open-loop GHPS under various hydrogeological conditions.

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  12. Hydrogeology and simulation of ground-water flow, Picatinny Arsenal and vicinity, Morris County, New Jersey

    USGS Publications Warehouse

    Voronin, L.M.; Rice, D.E.

    1996-01-01

    Ground-water flow in glacial sediments and bedrock at Picatinny Arsenal, N.J., was simulated by use of a three-dimensional finite-difference ground- water-flow model. The modeled area includes a 4.3-square-mile area that extends from Picatinny Lake to the Rockaway River. Most of the study area is bounded by the natural hydrologic boundaries of the ground-water system. eophysical logs, lithologic logs, particle-size data, and core data from selected wells and surface geophysical data were analyzed to define the hydrogeologic framework. Hydrogeologic sections and thickness maps define six permeable and three low-permeability layers that are represented in the model as aquifers and confining units, respectively. Hydrologic data incorporated in the model include a rate of recharge from precipitation of 22 inches per year, estimated from long-term precipitation records and estimates of evapotranspiration. Additional recharge from infiltration along valleys was estimated from measured discharge of springs along the adjacent valley walls and from estimates of runoff from upland drainage that flows to the valley floor. Horizontal and vertical hydraulic conductivities of permeable and low-permeability layers were estimated from examination of aquifer-test data, gamma-ray logs, borehole cuttings, and previously published data. Horizontal hydraulic conductivities in glacial sediments range from 10 to 380 feet per day. Vertical hydraulic conductivities of the low-permeability layers range from 0.01 to 0.7 feet per day. The model was calibrated by simulating steady-state conditions during 1989-93 and by closely matching simulated and measured ground-water levels, vertical ground-water-head differences, and streamflow gain and loss. Simulated steady-state potentiometric- surface maps produced for the six permeable layers indicate that ground water in the unconfined material within Picatinny Arsenal flows predominantly toward the center of the valley, where it discharges to Green Pond Brook. Beneath the upper confining unit, ground water flows southwestward, down the valley. Between First Street and Farley Avenue, the upper confining unit pinches out near the valley walls, resulting in a major input of water to, and causing a local potentiometric high in, the underlying aquifer layers. Ground-water-flow directions southwest of the southern arsenal boundary are predominantly to the Rockaway River.

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

    USGS Publications Warehouse

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

    1996-01-01

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

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

    USGS Publications Warehouse

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

    2008-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

    The Ebro Valley in the outskirts of Zaragoza (NE Spain) is severely affected by evaporite karstification, leading to multiple problems related to subsidence and sinkhole formation. In this work, a combination of inverse (mixing + mass-balance) and forward (reaction-path) geochemical calculations is applied for the quantification of the main karstification processes and seasonal variations in this area. The obtained results prove the suitability of the applied methodology for the characterization of similar problems in other areas with scarce geological and hydrogeological information. The hydrogeology and hydrochemistry of the system can be mainly attributed to the mixing of variable proportions of concentrated groundwater from the evaporitic aquifer and more dilute water from the overlying alluvial aquifer. The existence of a good connection between these aquifers is supported by: (1) the fast changes in the hydrochemistry of the karst aquifer related to recharge by irrigation, and (2) the deduced input of evaporitic groundwater in the alluvial materials. The evolution in some parts of the alluvial/evaporitic aquifer system is clearly dominated by the seasonal variations in the recharge by dilute irrigation waters (up to 95% of water volume in some sinkhole ponds), whereas other points seem to be clearly determined by the hydrochemistry of the concentrated evaporitic aquifer groundwater (up to 50% of the water volume in some springs). The following reactions, previous or superimposed to mixing processes, explain the observed hydrochemistry in the studied area: dissolution of halite (NaCl), gypsum (CaSO4ṡ2H2O)/anhydrite (CaSO4) and dolomite (CaMg(CO3)2), CO2(g) input and degassing and calcite (CaCO3) dissolution/precipitation. The modeling results suggest the existence of a large spatial variability in the composition of the evaporitic groundwater, mainly caused by large differences in the availability of halite in contact with the groundwater. Active subsidence associated with halite dissolution is expected to continue in the study area, together with the episodic increase of gypsum dissolution associated with the input of dilute irrigation waters.

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

    NASA Astrophysics Data System (ADS)

    Boutt, D. F.; Smith, Z.

    2012-12-01

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

  17. Hydrogeologic framework and salinity distribution of the Floridan aquifer system of Broward County, Florida

    USGS Publications Warehouse

    Reese, Ronald S.; Cunningham, Kevin J.

    2014-01-01

    Concerns about water-level decline and seawater intrusion in the surficial Biscayne aquifer, currently the principal source of water supply to Broward County, prompted a study to refine the hydrogeologic framework of the underlying Floridan aquifer system to evaluate its potential as an alternative source of supply. This report presents cross sections that illustrate the stratigraphy and hydrogeology in eastern Broward County; maps of the upper surfaces and thicknesses of several geologic formations or units within the Floridan aquifer system; and maps of two of the potentially productive water-bearing zones within the system, the Upper Floridan aquifer and the Avon Park permeable zone. An analysis of data on rock depositional textures, associated pore networks, and flow zones in the Floridan aquifer system shows that groundwater moves through the system in two ways. These data support a conceptual, dual-porosity model of the system wherein groundwater moves either as concentrated flow in discrete, thin bedding-plane vugs or zones of vuggy megaporosity, or as diffuse flow through rocks with primarily interparticle and moldic-particle porosity. Because considerable exchange of groundwater may occur between the zones of vuggy and matrix-dominated porosity, understanding the distribution of that porosity and flow zone types is important to evaluating the suitability of the several units within the Floridan aquifer system for managing the water through practices such as aquifer storage and recovery (ASR). The salinity of the water in the Floridan aquifer system is highest in the central part of the study area, and lower toward the north and south. Although salinity generally increases with depth, in the western part of the study area a zone of relatively high saline water is perched above water of lower salinity in the underlying Avon Park permeable zone. Overall, the areas of highest salinity in the aquifer system coincide with those with the lowest estimated transmissivity, so that the occurrence of perched saline water in the system may be the consequence of incompletely flushed connate water or intruded seawater. A seismic reflection profile along the Hillsboro Canal, at the northern edge of the study area, shows seven seismic-sag structures that are interpreted as downward deformation of overlying strata into collapsed deep cave systems. These structures may compromise the integrity of the confinement created by the underlying strata by allowing upconing of saline water from depth, which has implications for successful application of ASR and use of the Floridan aquifer system as an alternative water supply.

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

    NASA Astrophysics Data System (ADS)

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

    2009-12-01

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

  19. Seismicity Induced by Groundwater Recharge at Mt. Hood, Oregon, and its Implications for Hydrogeologic Properties.

    NASA Astrophysics Data System (ADS)

    Saar, M. O.; Manga, M.

    2002-12-01

    Earthquakes induced by human-caused changes in fluid pressure have been documented for many years. Examples include seismicity induced by filling reservoirs and by fluid injection or extraction. Less well-documented are seismic events that potentially are triggered by natural variations in groundwater recharge rates (e.g., Wolf et al., BSSA, 1997; Jimenez and Garcia-Fernandez, JVGR, 2000; Audin et al., GRL, 2002). Large groundwater recharge rates can occur in Volcanic Arcs such as the Oregon Cascades where annual precipitation is > 2 m of which > 50 % infiltrates the ground mostly during snowmelt in spring. As a result, infiltration rates of > 1 m per year concentrated during a few months can occur. Near-surface porosities are about 5-10 %. Thus, groundwater levels may fluctuate annually by about 10-20 m resulting in seasonal pore fluid pressure variations of about 1-2 x 105 Pa. Such large-amplitude, narrow-duration fluid pressure signals may allow investigation of seismicity induced by pore fluid pressure diffusion without the influence of engineered systems such as reservoirs. This kind of in-situ study of natural systems over large representative elementary volumes may allow determination of hydrologic parameters at spatial and temporal scales that are relevant for regional hydrogeology. Furthermore, natural hydrologic triggering of earthquakes that persist for decades provides insight into the state of stress in the crust and suggest long-term near-critical failure conditions. Here, we approximate the temporal variations in groundwater recharge with discharge in runoff-dominated streams at high elevations that show a peak in discharge during snow melt. Seismicity is evaluated as time series of daily number of earthquakes and seismic moments. Both stream discharge and seismicity are compared at equivalent frequency bands by applying segmented least-squares polynomial fits to the data. We find statistically significant correlation between groundwater recharge and seismicity at Mt. Hood, Oregon. We can use the time lag of about 120 days between the two records to estimate the regional hydraulic diffusivity (1 m2/s) and other hydrogeologic parameters (permeability ≈ 10-13 m2, vertical matrix compressibility ≈ 10-10 m2/N). These values are comparable with our results from coupled heat and groundwater flow studies that are based on bore hole temperature data at Mt. Hood.

  20. Using multiple geochemical tracers to characterize the hydrogeology of the submarine spring off Crescent Beach, Florida

    USGS Publications Warehouse

    Swarzenski, P.W.; Reich, C.D.; Spechler, R.M.; Kindinger, J.L.; Moore, W.S.

    2001-01-01

    A spectacular submarine spring is located about 4 km east of Crescent Beach, FL, in the Atlantic Ocean. The single vent feature of Crescent Beach Spring provides a unique opportunity to examine onshore-offshore hydrogeologic processes, as well as point source submarine ground water discharge. The Floridan aquifer system in northeastern Florida consists of Tertiary interspersed limestone and dolomite strata. Impermeable beds confine the water-bearing zones under artesian pressure. Miocene and younger confining strata have been eroded away at the vent feature, enabling direct hydrologic communication of Eocene ground water with coastal bottom waters. The spring water had a salinity of 6.02, which was immediately diluted by ambient seawater during advection/mixing. The concentration of major solutes in spring water and onshore well waters confirm a generalized easterly flow direction of artesian ground water. Nutrient concentrations were generally low in the reducing vent samples, and the majority of the total nitrogen species existed as NH3. The submarine ground water tracers, Rn-222 (1174 dpm I-1, dpm), methane (232 nM) and barium (294.5 nM) were all highly enriched in the spring water relative to ambient seawater. The concentrations of the reverse redox elements U, V and Mo were expectedly low in the submarine waters. The strontium isotope ratio of the vent water (87Sr/86Sr = 0.70798) suggests that the spring water contain an integrated signature indicative of Floridan aquifer system ground water. Additional Sr isotopic ratios from a series of surficial and Lower Floridan well samples suggest dynamic ground water mixing, and do not provide clear evidence for a single hydrogeologic water source at the spring vent. In this karst-dominated aquifer, such energetic mixing at the vent feature is expected, and would be facilitated by conduit and fractured flow. Radium isotope activities were utilized to estimate flow-path trajectories and to provide information on potential travel times between an onshore well and the spring. Using either 223Ra and 224Ra or 228Ra, and qualifying this approach with several key assumptions, estimates of water mass travel times from an upper Floridan well in Crescent Beach to the submarine vent feature (distance =4050 m) are in the order of ??? 0.01-0.1 m min-1. ?? 2001 Elsevier Science B.V. All rights reserved.

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

    SciTech Connect

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

    2002-05-21

    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.

  2. Hydrogeological characterization of the Heletz Sands Reservoir, Heletz (Israel) as a preliminary step towards CO2 injection experiments

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

    Hydrogeological characterization of the Heletz Sands Reservoir, Heletz (Israel) as a preliminary step towards CO2 injection experiments One the major components of the EU-FP7 funded MUSTANG project is to conduct a highly controlled series of CO2 injection experiments, aimed at determining field values of key CO2 trapping mechanisms such as dissolution and residual trapping and to establish a comprehensive and consistent dataset for model validation. Prior to injecting CO2 there is a need to achieve a sufficient degree of hydrogeological characterization of the reservoir. In what follows we present a sequence of hydrologic tests to be conducted at Heletz and their expected contribution to the understanding relevant hydrogeology. These include: 1) Chemical characterization of the formation fluid; 2) Flowing Fluid Electrical Conductivity log, aimed at determining the vertical variability of the reservoir permeability in the near well vicinity; 3) Water pulse and pumping tests, aimed at determining the reservoir scale hydraulic properties; 4) Thermal test, aimed at determining the value of the heat transfer coefficient from the reservoir to the borehole fluid, which is responsible for the heating of injected fluid in the borehole; 5) two-well injection and pumping of water and tracers test, in order to determine the impact of heterogeneity on the hydraulic parameters and to identify preferential flow paths in the reservoir. This paper presents the design and planning of the experiments, the results obtained in field and a preliminary interpretation.

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

    USGS Publications Warehouse

    Barr, G.L.

    1993-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

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

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

    NASA Astrophysics Data System (ADS)

    Thieme, D. M.; Denizman, C.

    2011-12-01

    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.

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

    USGS Publications Warehouse

    Fischer, John N.

    1986-01-01

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

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

    SciTech Connect

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

    1997-12-31

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

  8. Preliminary Test Results of Heshe Hydrogeological Experimental Well Station in Taiwan

    NASA Astrophysics Data System (ADS)

    Chuang, P.; Liu, C.; Lin, M.; Chan, W.; Lee, T.; Chia, Y.; Teng, M.; Liu, C.

    2013-12-01

    Safe disposal of radioactive waste is a critical issue for the development of nuclear energy. The design of final disposal system is based on the concept of multiple barriers which integrate the natural barriers and engineering barriers for long-term isolation of radioactive wastes. As groundwater is the major medium that can transport radionuclides to our living environment, it is essential to characterize groundwater flow at the disposal site. Taiwan is located at the boundary between the Eurasian plate and the Philippine Sea plate. Geologic formations are often fractured due to tectonic compression and extension. In this study, a well station for the research and development of hydrogeological techniques was established at the Experimental Forest of the National Taiwan University in central Taiwan. There are 10 testing wells, ranging in depth from 25 m to 100 m, at the station. The bedrock beneath the regolith is highly fractured mudstone. As fracture is the preferential pathway of the groundwater flow, the focus of in-situ tests is to investigate the location of permeable fractures and the connection of permeable fractures. Several field tests have been conducted, including geophysical logging, heat-pulse flowmeter, hydraulic test, tracer test and double packer test, for the development of advanced technologies to detect the preferential groundwater flow in fractured rocks.

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

    PubMed

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

    2008-01-01

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

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

    PubMed

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

    2009-12-01

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

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

    USGS Publications Warehouse

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

    1993-01-01

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

  12. Hydrogeology and Physical Characteristics of Water Samples at the Red River Aluminum Site, Stamps, Arkansas

    NASA Astrophysics Data System (ADS)

    Czarnecki, J. B.; Stanton, G. P.; Freiwald, D. A.

    2001-12-01

    The Red River Aluminum site near Stamps, Arkansas, contains waste piles of salt cake and metal byproducts from the smelting of aluminum. The waste piles are subjected to about 50 inches of rainfall a year, resulting in the dissolution of the salts and metal. To assess the potential threat to underlying ground-water resources at the site, its hydrogeology was characterized by measuring water levels and field parameters of water quality in 23 wells and at 2 surface-water sites. Seventeen of these monitor wells were constructed at various depths for this study to allow for the separate characterization of the shallow and deep ground-water systems, the calculation of vertical gradients, and the collection of water samples at different depths within the flow system. Lithologic descriptions from drill-hole cuttings and geophysical logs indicate the presence of interbedded sands, gravels, silts, and clays to depths of 65 feet. The regionally important Sparta aquifer underlies the site. Water levels in shallow wells indicate radial flow away from the salt-cake pile located near the center of the site. Flow in the deep system is to the west and southwest toward Bodcau Creek. Water-level data from eight piezometer nests indicate a downward hydraulic gradient from the shallow to deep systems across the site. Values of specific conductance (an indicator of dissolved salts) ranged from 215 to 196,200 microsiemens per centimeter and indicate that saline waters are being transported horizontally and vertically downward away from the site.

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

    NASA Astrophysics Data System (ADS)

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

    2008-11-01

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

  14. Detailed hydrogeological analysis of a deep-seated rockslide at the Gepatsch reservoir (Klasgarten, Austria)

    NASA Astrophysics Data System (ADS)

    Strauhal, Thomas; Loew, Simon; Holzmann, Michael; Zangerl, Christian

    2016-03-01

    The hydrogeology of the deep-seated, slowly creeping Klasgarten rockslide in Austria is investigated in this study based on detailed surface and subsurface field data, laboratory analyses, and analytical and numerical simulations. Field data are derived from several deep exploration and monitoring boreholes, an exploration drift located within the rockslide, and geological and geomorphological mapping. Particular attention is given to the pore pressure measurements and their temporal and spatial variability. These pore pressure variations are controlled by a thin layer of clayey fault gouge (representing the basal shear zone of the rockslide), a high-permeability rockslide mass, and moderately fractured paragneissic bedrock. Variably saturated equivalent-continuum hydraulic conductivities and storage properties are derived from packer tests, laboratory tests and optical televiewer images. These data sets are used for two-dimensional numerical groundwater models to study the flow-field and pore-pressure variations caused by the reservoir water-level fluctuations, the transient groundwater infiltration from snowmelt and precipitation along the slope, and the exploration drift. The strongest pressure transients in the rockslide are caused by reservoir level fluctuations and not the natural groundwater recharge, even at substantial distances from the reservoir. The response times are very short and only a minor distance-dependent attenuation is observed. The results of this study are essential to analyse the hydromechanical control of the deformation behaviour of rockslides adjacent to hydropower reservoirs. Further, it helps to understand how the formation of a rockslide can change the original bedrock aquifer.

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

    USGS Publications Warehouse

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

    1988-01-01

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

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

    PubMed

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

    2012-08-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

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

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

    SciTech Connect

    Ojiambo, S. Bwire

    1992-01-01

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

  19. A spatial DB model to simulate the road network efficiency in hydrogeological emergency

    NASA Astrophysics Data System (ADS)

    Michele, Mangiameli; Giuseppe, Mussumeci

    2015-12-01

    We deal with the theme of the simulation of risk analysis using a technological approach based on the integration of exclusively free and open source tools: PostgreSQL as Database Management System (DBMS) and Quantum GIS-GRASS as Geographic Information System (GIS) platform. The case study is represented by a seismic land in Sicily characterized by steep slopes and frequent instability phenomena. This area includes a city of about 30.000 inhabitants (Enna) that lies on the top of a mountain at about 990 m a.s.l.. The access to the city is assured by few and very winding roads that are also highly vulnerable to seismic and hydrogeological hazards. When exceptional rainfall events occur, the loss of efficiency of these roads should compromise timeliness and effectiveness of rescue operations. The data of the sample area have been structured into the adopted DBMS, and the connection to the GIS functionalities allows simulating the exceptional events. We analyzed the hazard, vulnerability and exposure related to these events and calculated the final risk defining three classes for each scenario: low (L), medium (M) and high (H). This study can be a valuable tool to prioritize risk levels and set priorities for intervention to the main road networks..

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

    SciTech Connect

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

    1994-07-01

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

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

    SciTech Connect

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

    1999-03-04

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

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

    USGS Publications Warehouse

    Mack, Thomas J.

    1995-01-01

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

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

    USGS Publications Warehouse

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

    2003-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Houben, Georg; Niard, Nadege; Tünnermeier, Torge; Himmelsbach, Thomas

    2009-05-01

    Shallow groundwater represents the main source for water supply in Kabul, Afghanistan. Detailed information on the hydrogeology of the Kabul Basin is therefore needed to improve the current supply situation and to develop a sustainable framework for future groundwater use. The basin is situated at the intersection of three major fault systems of partially translational and extensional character. It comprises three interconnected aquifers, 20-70 m thick, consisting of coarse sandy to gravely detritus originating from the surrounding mountains. The aquifers were deposited by three rivers flowing through the basin. The coarse aquifer material implies a high permeability. Deeper parts are affected by cementation of pore spaces, resulting in formation of semi-diagenetic conglomerates, causing decreased well yields. Usually the aquifers are covered by low-permeability loess which acts as an important protection layer. The main groundwater recharge occurs after the snowmelt from direct infiltration from the rivers. The steadily rising population is estimated to consume 30-40 million m3 groundwater per year which is contrasted by an estimated recharge of 20-45 million m3/a in wet years. The 2000-2005 drought has prevented significant recharge resulting in intense overexploitation indicated by falling groundwater levels.

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

    USGS Publications Warehouse

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

    2008-01-01

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

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

    SciTech Connect

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

    1989-01-01

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

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

    USGS Publications Warehouse

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

    1996-01-01

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

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

    USGS Publications Warehouse

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

    1989-01-01

    The hydrogeologic framework of the area around the Savannah River Plant, South Carolina consists of 2 to 3 separate water bearing units. In the northern half of the study area, the Barnwell and underlying McBean aquifers are considered one aquifer owing to the absence of the tan clay-confining unit between them. In the southern half of the study area they are separated by the tan clay into two aquifers. Underlying these aquifers, and separated from them by the green clay-confining unit, is the Congaree aquifer. Hydraulic conductivities of the aquifers range from 0.00000001 to 0.0001 ft/sec. Directions of groundwater flow in the Barnwell and McBean aquifers are to the north, with a component of flow directed downward across the green clay and into the Congaree aquifer. The direction of flow in the Congaree aquifer is to the northwest. Water in these aquifers evolves from an acidic (pH < 6.5) mixed-cation type in the Barnwell aquifer to an alkaline (pH > 8) calcium bicarbonate water in the Congaree aquifer. Laboratory experiments indicate that reactions between sediments of the Barnwell aquifer and a salt-solution waste to be stored at the study area would significantly reduce the permeability of the sediment, thereby limiting the movement of the waste in groundwater at the site. (USGS)

  9. Hydrogeological properties of fault zones in a karstified carbonate aquifer (Northern Calcareous Alps, Austria)

    NASA Astrophysics Data System (ADS)

    Bauer, H.; Schröckenfuchs, T. C.; Decker, K.

    2016-03-01

    This study presents a comparative, field-based hydrogeological characterization of exhumed, inactive fault zones in low-porosity Triassic dolostones and limestones of the Hochschwab massif, a carbonate unit of high economic importance supplying 60 % of the drinking water of Austria's capital, Vienna. Cataclastic rocks and sheared, strongly cemented breccias form low-permeability (<1 mD) domains along faults. Fractured rocks with fracture densities varying by a factor of 10 and fracture porosities varying by a factor of 3, and dilation breccias with average porosities >3 % and permeabilities >1,000 mD form high-permeability domains. With respect to fault-zone architecture and rock content, which is demonstrated to be different for dolostone and limestone, four types of faults are presented. Faults with single-stranded minor fault cores, faults with single-stranded permeable fault cores, and faults with multiple-stranded fault cores are seen as conduits. Faults with single-stranded impermeable fault cores are seen as conduit-barrier systems. Karstic carbonate dissolution occurs along fault cores in limestones and, to a lesser degree, dolostones and creates superposed high-permeability conduits. On a regional scale, faults of a particular deformation event have to be viewed as forming a network of flow conduits directing recharge more or less rapidly towards the water table and the springs. Sections of impermeable fault cores only very locally have the potential to create barriers.

  10. Hydrogeology and hydrochemistry of a shallow alluvial aquifer, western Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Al-Shaibani, Abdulaziz M.

    2008-02-01

    A hydrogeological and hydrochemical study was conducted on a shallow alluvial aquifer, Wadi Wajj, in western Saudi Arabia to assess the influence of protection measures on groundwater quality. The hydrochemistry was assessed up-gradient and down-gradient from potential contamination sources in the main city in dry and wet seasons prior to and after the installation of major drainage and wastewater facilities. Wadi Wajj is an unconfined aquifer where water is stored and transmitted through fractured and weathered bedrock and the overlying alluvial sediments. Natural recharge to the aquifer is about 5% of rainfall-runoff. Hydrochemistry of the aquifer shows temporal and seasonal changes as influenced by protection measures and rainfall runoff. Both groundwater and runoff showed similar chemical signature, which is mostly of chloride-sulfate-bicarbonate and sodium-calcium type. Groundwater downstream of the city, though of poorer quality than upstream, showed significant improvement after the installation of a concrete runoff tunnel and a wastewater treatment plant. Concentrations of many of the groundwater quality indicators (e.g., TDS, coliform bacteria, and nitrate) exceed US Environmental Protection Agency drinking-water standards. Heavy metal content is, however, within allowable limits by local and international standards. The chemical analyses also suggest the strong influence of stream runoff and sewage water on the groundwater quality.

  11. Hydrogeology of the upper and middle Verde River watersheds, central Arizona

    USGS Publications Warehouse

    Blasch, Kyle W.; Hoffmann, John P.; Graser, Leslie F.; Bryson, Jeannie R.; Flint, Alan L.

    2006-01-01

    The upper and middle Verde River watersheds in central Arizona are primarily in Yavapai County, which in 1999 was determined to be the fastest growing rural county in the United States; by 2050 the population is projected to more than double its current size (132,000 in 2000). This study combines climatic, surface-water, ground-water, water-chemistry, and geologic data to describe the hydrogeologic systems within the upper and middle Verde River watersheds and to provide a conceptual understanding of the ground-water flow system. The study area includes the Big Chino and Little Chino subbasins in the upper Verde River watershed and the Verde Valley subbasin in the middle Verde Rive watershed...more...A geochemical mixing model was used to quantify fractions of ground-water sources to the Verde River from various parts of the study area. Most of the water in the uppermost 0.2 mile of the Verde River is from the Little Chino subbasin, and the remainder is from the Big Chino subbasin. Discharge from a system of springs increases base flow to about 17 cubic feet per second within the next 2 miles of the river. Ground water that discharges at these springs is derived from the western part of the Coconino Plateau, from the Big Chino subbasin, and from the Little Chino subbasin. More...

  12. Reconstitution of Holocene Climate Events in Western Africa from palynological proxies through hydrogeological modelling

    NASA Astrophysics Data System (ADS)

    Maugis, Pascal; Aguiar, Lazar; Grenier, Christophe

    2010-05-01

    The Niayes of Senegal are sahelian inter-dunal fens, that hosted an azonal sub-guinean vegetation during the Holocene thanks to the availability of fresh groundwater despite contrasted climatic conditions. Exploratory scenario-based modeling of the zonal hydrogeology has been conducted for different periods with the Cast3M code. The results show that the delay in the onset of humid vegetation ca. 10 ky cal. BP could be ecosystemic and denote a start of the African Humid Period (AHP) ca. 11.5 ky cal. BP. Alternatively, the AHP could have started earlier while its beneficial effects would have been canceled by low sea levels. Vegetation degradation around 7.5 ky cal. BP is shown to have resulted from a climate minoration, that possibly alleviated until 4 ky cal. BP. The rising watertable allowed the degraded forest to persist during that period however. The forest expansion that followed ca. 3.5 ky cal. BP had then clearly a climatic origin. The interpretation of pollens for climate research requires a careful filtering-out of local groundwater availability.

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

    SciTech Connect

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

    2012-02-10

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

  14. Detailed hydrogeological analysis of a deep-seated rockslide at the Gepatsch reservoir (Klasgarten, Austria)

    NASA Astrophysics Data System (ADS)

    Strauhal, Thomas; Loew, Simon; Holzmann, Michael; Zangerl, Christian

    2015-12-01

    The hydrogeology of the deep-seated, slowly creeping Klasgarten rockslide in Austria is investigated in this study based on detailed surface and subsurface field data, laboratory analyses, and analytical and numerical simulations. Field data are derived from several deep exploration and monitoring boreholes, an exploration drift located within the rockslide, and geological and geomorphological mapping. Particular attention is given to the pore pressure measurements and their temporal and spatial variability. These pore pressure variations are controlled by a thin layer of clayey fault gouge (representing the basal shear zone of the rockslide), a high-permeability rockslide mass, and moderately fractured paragneissic bedrock. Variably saturated equivalent-continuum hydraulic conductivities and storage properties are derived from packer tests, laboratory tests and optical televiewer images. These data sets are used for two-dimensional numerical groundwater models to study the flow-field and pore-pressure variations caused by the reservoir water-level fluctuations, the transient groundwater infiltration from snowmelt and precipitation along the slope, and the exploration drift. The strongest pressure transients in the rockslide are caused by reservoir level fluctuations and not the natural groundwater recharge, even at substantial distances from the reservoir. The response times are very short and only a minor distance-dependent attenuation is observed. The results of this study are essential to analyse the hydromechanical control of the deformation behaviour of rockslides adjacent to hydropower reservoirs. Further, it helps to understand how the formation of a rockslide can change the original bedrock aquifer.

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

    NASA Astrophysics Data System (ADS)

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

    2012-09-01

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

  16. Model study of the regional hydrogeologic regime, Roosevelt Hot Springs, Utah

    SciTech Connect

    Smith, L.

    1980-05-01

    A regional hydrogeologic model is used to investigate the potential for water recharging in the Tushar Mountains to move at depth beneath the Mineral Mountains to discharge in Milford Valley. Simulations carried out over a range of water table positions and assumed depths to a lower impermeable boundary suggest it is unlikely that the topographic configuration alone could drive such a flow system. Specific geologic conditions are necessary if interbasin flow is to occur. However, simulations based on a simplified hydrologic model of the regional geology suggest this is not the case. A regional hydraulic anisotropy greater than 10:1 (Kx/Kz) leads to interflow if the granitic Mineral Mountain pluton and the volcanics in the Tushar Mountains have similar hydraulic conductivities. If either of these units is more nearly isotropic or if the granitic rocks have a greater vertical than horizontal hydraulic conductivity, no interbasin flow is observed. On the basis of available geologic evidence, this latter case seems to be the most likely.

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

    SciTech Connect

    McCord, J.; Treadway, A.

    1993-11-01

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

  18. Association of hydrogeological factors in temporal variations of fluoride concentration in a crystalline aquifer in India

    NASA Astrophysics Data System (ADS)

    Sreedevi, P. D.; Ahmed, S.; Made, B.; Ledoux, E.; Gandolfi, J. M.

    2006-05-01

    The major part of groundwater in India is found in granitic aquifers. Fluoride in groundwater from a crystalline aquifer in a semi-arid region of granitic rocks in India, known as Maheshwaram watershed, was analyzed for spatial and temporal variability during 1999-2002 to assess the effect of hydrogeological factors on fluoride concentration. Samples were collected from 32 representative wells in the area for the pre- and post-monsoon seasons and analyzed for F content. The CHESS computer program was used to calculate ionic activities of aqueous species and the mineral saturation index (SI) for calcite and fluorite. The GARDENIA computer program was used to calculate the recharge values in the study area. The influences of dissolution kinetics of fluoride minerals and recharge from rainfall on fluoride concentration were of interest and results clearly indicate that fluoride content in groundwater depends on the interaction period of groundwater with host rock. Results could also be utilized for designing remedial measures particularly with dilution method in an optimal way.

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

    USGS Publications Warehouse

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

    2008-01-01

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

  20. Hydrogeology and processes of acid neutralization in Cadwell Creek watershed, Quabbin Reservation, Massachusetts. Technical completion report

    SciTech Connect

    Leonard, W.C.; Yuretich, R.F.; Pohanka, S.J.

    1984-12-01

    A detailed hydrogeological and geochemical study was undertaken of Cadwell Creek, a small (7.28 sq km) forested watershed on the west side of Quabbin Reservoir in central Massachusetts. Paleozoic crystalline metamorphic rocks comprise the bedrock in the watershed and are the source material for the glacial till, the main aquifer. During 1983, 41% of incoming precipitation was returned to the atmosphere as evapotranspiration and 55% left the watershed as stream runoff. Furthermore, 45% of this stream runoff was groundwater discharge or base flow. Specific conductivity and pH, both field and aerated, showed strong correlations with the groundwater velocity and hydraulic gradient. The pH ranged from 4.7 to 7.0 and the specific conductivity from 25 to 70 micromhos/cm. Two-thirds of the total base flow comes from areas with low pH and low specific conductivity, i.e., is incompletely neutralized. Because of unusual hydrologic and topographic relationships, Cadwell Creek alone should not be used as a standard for all streams draining into Quabbin Reservoir.

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

    SciTech Connect

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

    1993-03-01

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

  2. Hydrogeology of the Cambrian-Ordovician aquifer system at a test well in northeastern Illinois

    USGS Publications Warehouse

    Nicholas, J.R.; Sherrill, M.G.; Young, H.L.

    1987-01-01

    A 3,475-ft-deep test well was drilled in northeastern Illinois near Lake Michigan and the Illinois-Wisconsin State line as part of a regional hydrologic study of the Cambrian-Ordovician aquifer. The well penetrates the Cambrian-Ordovician aquifer system and 40 ft of Precambrian granite. From oldest to youngest the aquifer system consists of the lower Mount Simon aquifer, Mount Simon confining unit, Elmhurst-Mount Simon aquifer, Eau Claire confining unit, Ironton-Galesville aquifer, Franconia confining unit, St. Peter aquifer, and an upper confining unit composed of the Glenwood Formation, Galena Dolomite and Platteville Limestone, and Maquoketa Shale. Aquifer tests were performed on hydrogeologic units that were isolated with inflatable packers. Results indicate that the Ironton-Galesville aquifer has the highest hydraulic conductivity - 10 ft/day. The St. Peter and Elmhurst-Mount Simon aquifers have hydraulic conductivities of 1.8 and 1.5 ft/day, respectively. The Mount Simon confining bed has a hydraulic conductivity of 1.3 ft/day. The Mount Simon confining unit confines saline water present in the lower Mount Simon aquifer. The dissolved solids concentration in water from this aquifer is > than 55,000 mg/L, and the head is at least 50 ft higher than heads in any of the overlying Cambrian and Ordovician aquifers. (USGS)

  3. Hydrogeologic investigations of flow in fractured tuffs, Rainier Mesa, Nevada Test Site

    NASA Astrophysics Data System (ADS)

    Russell, Charles E.; Hess, John W.; Tyler, Scott W.

    Rainier Mesa, a primary site for nuclear testing, is located in the north central area of the Nevada Test Site, and is composed of highly fractured and altered Tertiary tuffs. A hydrogeologic study was conducted within the mesa concentrating on several parameters: the source of ground water found in Rainier Mesa, period of principal recharge, ground-water travel time between the mesa surface and the tunnel level, period of hydraulic response, and total amount of recharge per year to U12n Tunnel recharge basin. The data base consists of: the precipitation record, discharge record of seeps within Rainier Mesa, the gross chemistry and stable isotopic composition of these seeps, and two tracer studies conducted from the mesa surface. Results indicate that ground water is of recent meteoric origin, winter is the period of principal recharge, the period of hydrologic response is at least four months, the total recharge is approximately eight percent of the precipitation which falls on the U12n recharge basin, and travel time is estimated as greater than one year and less than six. These observations describe an environment which has been subjected to nuclear testing since 1957. It is certain that this testing has altered the hydrogeochemical environment and it is suspected that some alteration of the hydraulic system has also occurred.

  4. The influence of hydrogeological disturbance and mining on coal seam microbial communities.

    PubMed

    Raudsepp, M J; Gagen, E J; Evans, P; Tyson, G W; Golding, S D; Southam, G

    2016-03-01

    The microbial communities present in two underground coal mines in the Bowen Basin, Queensland, Australia, were investigated to deduce the effect of pumping and mining on subsurface methanogens and methanotrophs. The micro-organisms in pumped water from the actively mined areas, as well as, pre- and post-mining formation waters were analyzed using 16S rRNA gene amplicon sequencing. The methane stable isotope composition of Bowen Basin coal seam indicates that methanogenesis has occurred in the geological past. More recently at the mine site, changing groundwater flow dynamics and the introduction of oxygen in the subsurface has increased microbial biomass and diversity. Consistent with microbial communities found in other coal seam environments, pumped coal mine waters from the subsurface were dominated by bacteria belonging to the genera Pseudomonas and the family Rhodocyclaceae. These environments and bacterial communities supported a methanogen population, including Methanobacteriaceae, Methanococcaceae and Methanosaeta. However, one of the most ubiquitous micro-organisms in anoxic coal mine waters belonged to the family 'Candidatus Methanoperedenaceae'. As the Archaeal family 'Candidatus Methanoperedenaceae' has not been extensively defined, the one studied species in the family is capable of anaerobic methane oxidation coupled to nitrate reduction. This introduces the possibility that a methane cycle between archaeal methanogenesis and methanotrophy may exist in the anoxic waters of the coal seam after hydrogeological disturbance. PMID:26541089

  5. Hydrostratigraphic framework and hydrogeological behaviour of the Mancha Oriental System (SE Spain)

    NASA Astrophysics Data System (ADS)

    Sanz, David; Gómez-Alday, Juan José; Castaño, Santiago; Moratalla, Angel; de Las Heras, Jorge; Martínez-Alfaro, Pedro Emilio

    2009-09-01

    The Mancha Oriental System (MOS) has a surface area of 7,260 km2, making it one of the largest carbonate aquifer systems in Spain. The system sustains about 1,000 km2 of irrigated crops and supplies groundwater to 275,000 inhabitants. The economic transformation brought about by the development of extensive irrigated cropland has led to a water-balance disequilibrium of about 75 million m3/year. This input-output deficit has negative consequences in the quantity and quality of the available resources, in the river-aquifer relationship, and in the associated ecosystems as well. To understand the hydrogeological behaviour of the system, it is necessary to design a conceptual model. Further, the conceptualisation of a groundwater flow system is a requirement of the European Water Framework Directive for the characterisation of groundwater bodies. The robustness of the conceptual model depends heavily on the user capability of representing the real system. In this work, a multidisciplinary approach has been used to represent the three-dimensional geological framework and the groundwater flow conceptualisation of the MOS. Data management and three-dimensional visualisation have been carried out by means of geographical information system (GIS) tools and software for contouring and three-dimensional surface mapping.

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

    NASA Astrophysics Data System (ADS)

    Dafny, Elad; Silburn, D. Mark

    2014-05-01

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

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

    PubMed

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

    2013-09-30

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

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

    SciTech Connect

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

    1999-03-01

    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.

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

    SciTech Connect

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

    2011-01-01

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

  10. Hydrogeology and leachate movement near two chemical-waste sites in Oswego County, New York

    USGS Publications Warehouse

    Anderson, H.R.; Miller, T.S.

    1986-01-01

    Forty-five observation wells and test holes were installed at two chemical waste disposal sites in Oswego County, New York, to evaluate the hydrogeologic conditions and the rate and direction of leachate migration. At the site near Oswego groundwater moves northward at an average velocity of 0.4 ft/day through unconsolidated glacial deposits and discharges into White Creek and Wine Creek, which border the site and discharge to Lake Ontario. Leaking barrels by chemical wastes have contaminated the groundwater within the site, as evidenced by detection of 10 ' priority pollutant ' organic compounds, and elevated values of specific conductance, chloride, arsenic, lead, and mercury. At the site near Fulton, where 8,000 barrels of chemical wastes are buried, groundwater in the sandy surficial aquifer bordering the landfill on the south and east moves southward and eastward at an average velocity of 2.8 ft/day and discharges to Bell Creek, which discharges to the Oswego River, or moves beneath the landfill. Leachate is migrating eastward, southeastward, and southwestward, as evidenced by elevated values of specific conductance, temperature, and concentrations of several trace metals at wells east, southeast, and southwest of the site. (USGS)

  11. Geologic and hydrogeologic frameworks of the Biscayne aquifer in central Miami-Dade County, Florida

    USGS Publications Warehouse

    Wacker, Michael A.; Cunningham, Kevin J.; Williams, John H.

    2014-01-01

    Evaluations of the lithostratigraphy, lithofacies, paleontology, ichnology, depositional environments, and cyclostratigraphy from 11 test coreholes were linked to geophysical interpretations, and to results of hydraulic slug tests of six test coreholes at the Snapper Creek Well Field (SCWF), to construct geologic and hydrogeologic frameworks for the study area in central Miami-Dade County, Florida. The resulting geologic and hydrogeologic frameworks are consistent with those recently described for the Biscayne aquifer in the nearby Lake Belt area in Miami-Dade County and link the Lake Belt area frameworks with those developed for the SCWF study area. The hydrogeologic framework is characterized by a triple-porosity pore system of (1) matrix porosity (mainly mesoporous interparticle porosity, moldic porosity, and mesoporous to megaporous separate vugs), which under dynamic conditions, produces limited flow; (2) megaporous, touching-vug porosity that commonly forms stratiform groundwater passageways; and (3) conduit porosity, including bedding-plane vugs, decimeter-scale diameter vertical solution pipes, and meter-scale cavernous vugs. The various pore types and associated permeabilities generally have a predictable vertical spatial distribution related to the cyclostratigraphy. The Biscayne aquifer within the study area can be described as two major flow units separated by a single middle semiconfining unit. The upper Biscayne aquifer flow unit is present mainly within the Miami Limestone at the top of the aquifer and has the greatest hydraulic conductivity values, with a mean of 8,200 feet per day. The middle semiconfining unit, mainly within the upper Fort Thompson Formation, comprises continuous to discontinuous zones with (1) matrix porosity; (2) leaky, low permeability layers that may have up to centimeter-scale vuggy porosity with higher vertical permeability than horizontal permeability; and (3) stratiform flow zones composed of fossil moldic porosity, burrow related vugs, or irregular vugs. Flow zones with a mean hydraulic conductivity of 2,600 feet per day are present within the middle semiconfining unit, but none of the flow zones are continuous across the study area. The lower Biscayne aquifer flow unit comprises a group of flow zones in the lower part of the aquifer. These flow zones are present in the lower part of the Fort Thompson Formation and in some cases within the limestone or sandstone or both in the uppermost part of the Pinecrest Sand Member of the Tamiami Formation. The mean hydraulic conductivity of major flow zones within the lower Biscayne aquifer flow unit is 5,900 feet per day, and the mean value for minor flow zones is 2,900 feet per day. A semiconfining unit is present beneath the Biscayne aquifer. The boundary between the two hydrologic units is at the top or near the top of the Pinecrest Sand Member of the Tamiami Formation. The lower semiconfining unit has a hydraulic conductivity of less than 350 feet per day. The most productive zones of groundwater flow within the two Biscayne aquifer flow units have a characteristic pore system dominated by stratiform megaporosity related to selective dissolution of an Ophiomorpha-dominated ichnofabric. In the upper flow unit, decimeter-scale vertical solution pipes that are common in some areas of the SCWF study area contribute to high vertical permeability compared to that in areas without the pipes. Cross-hole flowmeter data collected from the SCWF test coreholes show that the distribution of vuggy porosity, matrix porosity, and permeability within the Biscayne aquifer of the SCWF is highly heterogeneous and anisotropic. Groundwater withdrawals from production well fields in southeastern Florida may be inducing recharge of the Biscayne aquifer from canals near the well fields that are used for water-management functions, such as flood control and well-field pumping. The SCWF was chosen as a location within Miami-Dade County to study the potential for such recharge to the Biscayne aquifer from the C–2 (Snapper Creek) canal that roughly divides the well field in half. Geologic, hydrogeologic, and hydraulic information on the aquifer collected during construction of monitoring wells within the SCWF could be used to evaluate the groundwater flow budget at the well-field scale.

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

    NASA Astrophysics Data System (ADS)

    Mateus, C.; Tullos, D.

    2014-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

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

    USGS Publications Warehouse

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

    2013-01-01

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

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

    SciTech Connect

    Geng, Q.Z. |; Girard, G.; Ledoux, E.

    1996-03-01

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

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

    USGS Publications Warehouse

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

    1998-01-01

    The coastal aquifer system of southern Oahu, Hawaii, USA, consists of highly permeable volcanic aquifers overlain by weathered volcanic rocks and interbedded marine and terrestrial sediments of both high and low permeability. The weathered volcanic rocks and sediments are collectively known as caprock, because they impede the free discharge of groundwater from the underlying volcanic aquifers. A cross-sectional groundwater flow and transport model was used to evaluate the hydrogeologic controls on the regional flow system in southwestern Oahu. Controls considered were: (a) overall caprock hydraulic conductivity; and (b) stratigraphic variations of hydraulic conductivity in the caprock. Within the caprock, variations in hydraulic conductivity, caused by stratigraphy or discontinuities of the stratigraphic units, are a major control on the direction of groundwater flow and the distribution of water levels and salinity. Results of cross-sectional modeling confirm the general groundwater flow pattern that would be expected in a layered coastal system. Ground-water flow is: (a) predominantly upward in the low-permeability sedimentary units; and (b) predominantly horizontal in the high-permeability sedimentary units.

  18. The Influence of Subsurface Karst Terrain on Hydrology and Hydrogeology in Southwestern Victoria, Australia

    NASA Astrophysics Data System (ADS)

    Perveen, F.; Webb, J.; Dresel, E.; Hekmeijer, P.; Zydor, H.

    2012-12-01

    A detailed study, in collaboration with Department of Primary Industries (DPI), Victoria, has been carried out in three small subcatchments of southwestern Victoria (total area 8.4 km2), which are characterised by varying degrees of influence of a subsurface karst terrain. Lithological logs and downhole geophysics (gamma and bulk conductivity - EM39) on 15 bores within the catchments were supplemented by 2D electrical resistivity vertical profiling, and showed that the middle to late Miocene Port Campbell Limestone is present at shallow depths (~5 m) in two catchments, and somewhat deeper (>70 m) in the third catchment. The limestone is overlain by early Pliocene clay-rich Dorodong Sands. The topography of the third catchment is characterised by shallow closed depressions. Detailed hydrogeological cross-sections using groundwater levels in the bores show closed depressions within the potentiometric surface, that are attributed to the presence of subsurface conduits within the highly permeable limestone, verified by the variable hydraulic conductivity values ( 0.005 - 0.545m/day) obtained from single borehole recovery tests. Stream hydrographs reveal that there is virtually no surface runoff from one subcatchment, due to leakage into a conduit in the underlying limestone. A perched water table is also found in the same area. Thus the study area shows the typical karst features of a highly heterogeneous terrain with massive connectivity between surface water and groundwater regimes, despite the fact that the limestone is overlain by the clay-rich Dorodong Sands.

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

    NASA Astrophysics Data System (ADS)

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

    2011-05-01

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

  20. Hydrogeologic Processes Impacting Storage, Fate, and Transport of Chloride from Road Salt in Urban Riparian Aquifers.

    PubMed

    Ledford, Sarah H; Lautz, Laura K; Stella, John C

    2016-05-17

    Detrimental effects of road salt runoff on urban streams are compounded by its facilitated routing via storm drains, ditches, and flood channels. Elevated in-stream salinity may also result from seasonal storage and discharge of chloride in groundwater, and previous work has hypothesized that groundwater discharge to streams may have the effect of diluting stream chloride concentrations in winter and enriching them in summer. However, the hydrogeological processes controlling these patterns have not been thoroughly investigated. Our research focuses on an urban stream and floodplain system in Syracuse, NY, to understand how groundwater and surface water exchange impacts chloride storage, fate, and transport. We created a 3D groundwater flow and solute transport model of the floodplain, calibrated to the distributions of floodplain hydraulic heads and groundwater fluxes to the stream throughout the reach. We used a sensitivity analysis to calibrate and evaluate the influence of model parameters, and compared model outputs to field observations. The main source mechanism of chloride to the floodplain aquifer was high-concentration, overbank flood events in winter that directly recharged groundwater. The modeled residence time and storage capacity of the aquifer indicate that restoration projects designed to promote floodplain reconnection and the frequency of overbank flooding in winter have the potential to temporarily store chloride in groundwater, buffer surface water concentrations, and reduce stream concentrations following periods of road salting. PMID:27077530

  1. A new quasi-3D unsaturated-saturated hydrogeologic model of the Plateau de Saclay (France)

    NASA Astrophysics Data System (ADS)

    Renard, François; Tognelli, Antoine

    2016-04-01

    A new hydrogeologic model is developed for the Plateau de Saclay (20 km south-west of Paris, France), which covers an area of 74 km2. It is based on a 2D model of the Fontainebleau Sands aquifer, combined with a 1D model of the unsaturated zone, taking into account the spatial variability of the groundwater permeability field and the thickness of the unsaturated zone. The paper focuses on the estimation of a triplet of parameters (permeability, infiltration and effective porosity), based on transient flow simulations. First, the permeability is obtained by inversion of mean hydraulic head data for different values of infiltration. Then, infiltration and effective porosity are determined by using transient flow simulations and fitting the hydraulic head measurements at several piezometers over the 1970-2014 period. The infiltration is estimated at between 125 and 150 mm/yr, the mean permeability between 2 · 10-5 and 6 · 10-5 m/s, and the effective porosity between 20% and 30%. Furthermore, the role of the unsaturated zone is quantified and the induced delay is estimated at about 20 years in the case of the transport of a tracer.

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

    NASA Astrophysics Data System (ADS)

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

    2008-03-01

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

  3. Borehole Fluid Logging Methods for Hydrogeologic Characterization: What Have We Learned in Twenty-Five Years?

    NASA Astrophysics Data System (ADS)

    Pedler, W. H.

    2012-12-01

    Over the past twenty-five years, several methods have been developed and enhanced to improve the capability to characterize hydraulically conductive intervals in wellbores. The principal, and most commonly employed, methods include the heat pulse flow meter, the electromagnetic flow meter, and hydrophysical (or FEC) logging. The primary objective of each of these methods is to identify the depth of the water bearing (conductive) intervals and estimate the volumetric flow rate of each conductive interval under one or more pressure conditions. The pressure conditions under which measurements are taken include ambient (native), pumping or injection of the subject well and/or pumping a well proximate to the subject (cross-hole testing). During this period, these methods have been applied in effectively all of the hydrogeologic systems including fractured bedrock, fractured sandstones, porous alluvium, massive and fractured clays, karst, and volcanics. Project applications range from contaminant fate and transport, geotechnical, mining and water supply. These methods evaluate flow in the wellbore fluid column by applying either stationary and/or profile-type logging measurements. Each of these methods evaluates flow in a distinct and unique way and, as such, there are limitations associated with each measurement method. The analytical methods to reduce the field data to the stated objectives also vary in complexity between the different methods. Numerous field and laboratory comparative studies have been conducted to evaluate, compare and verify the results of these methods. This poster will present a summary of these methods, recent updates, variety of applications and associated limitations.

  4. Detailed hydrogeological investigation and conceptual modelling of an Alpine Main Valley crossed by the Brenner Bases tunnel

    NASA Astrophysics Data System (ADS)

    Burger, Ulrich; San Nicolo, Lorenz; Zurlo, Raffaele

    2014-05-01

    The Brenner Base Tunnel (BBT) will cross the Isarco Valley near the village of Fortezza (BZ) at a depth of approximately 20 m below the riverbed of the Isarco river. The design of this roughly 1 km long stretch through alluvial sediments and below groundwater level required detailed knowledge of the prevailing hydrogeological conditions. In particular, it was necessary to determine if dewatering procedures were feasible and what the impacts on natural water flows in the aquifer after completion of the infrastructure will be. The study area is a typical Alpine valley, filled with alluvial sediments to a maximum depth of approximately 120m. The valley is bounded by granitic rocks with regional, water saturated main fault zones. In addition to the Isarco River, the area is shaped by two lateral rivers. The deposits of these lateral rivers form main alluvial fans. The aim of the study was to study the geological structure and the hydrogeological behaviour of this alpine valley. Therefor a detailed geological and hydrogeological investigation program was carried out, including a geological detailed mapping, construction of 40 boreholes (max. depth 120m; 35 are equipped to groundwater monitoring wells) and 5 large wells (55m - 87m). In order to determine the hydrodynamic characteristics of the aquifer in the valley, several pumping tests were carried out in different study stages: Stage 1: preliminary hydrogeological characterization of the area based on a pumping test carried out in the first well (100l/s pumping for 14 days). Stage 2: individual step tests and constant rate tests in additional four wells Stage 3: main pumping test including all the five wells with a maximum pumping rate of 450l/s for 14 days. The main topics oh the presentation are: - Overview of the BBT-project, the investigation area and investigation program - Description of the validated geological model of the main alpine valley - Results of the various hydraulic tests performed in the individual wells (step test and constant rate test) - Results of the long-term pumping test. Based on the results of these tests a Conceptual hydrogeological model of the area and the dewatering concept will be presented. The conceptual model is the basis for the numerical model of groundwater flow developed and calibrated in two successive phases (see abstract: L. San Nicolò, U. Burger, R. Zurlo).

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

    NASA Astrophysics Data System (ADS)

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

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

  6. Hydrogeology and Aquifer Storage and Recovery Performance in the Upper Floridan Aquifer, Southern Florida

    USGS Publications Warehouse

    Reese, Ronald S.; Alvarez-Zarikian, Carlos A.

    2007-01-01

    Well construction, hydraulic well test, ambient water-quality, and cycle test data were inventoried and compiled for 30 aquifer storage and recovery facilities constructed in the Floridan aquifer system in southern Florida. Most of the facilities are operated by local municipalities or counties in coastal areas, but five sites are currently being evaluated as part of the Comprehensive Everglades Restoration Plan. The relative performance of all sites with adequate cycle test data was determined, and compared with four hydrogeologic and design factors that may affect recovery efficiency. Testing or operational cycles include recharge, storage, and recovery periods that each last days or months. Cycle test data calculations were made including the potable water (chloride concentration of less than 250 milligrams per liter) recovery efficiency per cycle, total recovery efficiency per cycle, and cumulative potable water recovery efficiencies for all of the cycles at each site. The potable water recovery efficiency is the percentage of the total amount of potable water recharged for each cycle that is recovered; potable water recovery efficiency calculations (per cycle and cumulative) were the primary measures used to evaluate site performance in this study. Total recovery efficiency, which is the percent recovery at the end of each cycle, however, can be substantially higher and is the performance measure normally used in the operation of water-treatment plants. The Upper Floridan aquifer of the Floridan aquifer system currently is being used, or planned for use, at 29 of the aquifer storage and recovery sites. The Upper Floridan aquifer is continuous throughout southern Florida, and its overlying confinement is generally good; however, the aquifer contains brackish to saline ground water that can greatly affect freshwater storage and recovery due to dispersive mixing within the aquifer. The hydrogeology of the Upper Floridan varies in southern Florida; confinement between flow zones is better in southwestern Florida than in southeastern Florida. Vertical hydraulic conductivity in the upper part of the aquifer also may be higher in southeastern Florida because of unconformities present at formation contacts within the aquifer that may be better developed in this area. Recovery efficiencies per cycle varied widely. Eight sites had recovery efficiencies of less than about 10 percent for the first cycle, and three of these sites had not yet achieved recoveries exceeding 10 percent, even after three to five cycles. The highest recovery efficiency achieved per cycle was 94 percent. Three southeastern coastal sites and two southwestern coastal sites have achieved potable water recoveries per cycle exceeding 60 percent. One of the southeastern coastal sites and both of the southwestern coastal sites achieved good recoveries, even with long storage periods (from 174 to 191 days). The high recovery efficiencies for some cycles apparently resulted from water banking?an operational approach whereby an initial cycle with a large recharge volume of water is followed by cycles with much smaller recharge volume. This practice flushes out the aquifer around the well and builds up a buffer zone that can maintain high recovery efficiency in the subsequent cycles. The relative performance of all sites with adequate cycle test data was determined. Performance was arbitrarily grouped into ?high? (greater than 40 percent), ?medium? (between 20 and 40 percent), and ?low? (less than 20 percent) categories based primarily on their cumulative recovery efficiency for the first seven cycles, or projected to seven cycles if fewer cycles were conducted. The ratings of three sites, considered to be borderline, were modified using the overall recharge rate derived from the cumulative recharge volumes. A higher overall recharge rate (greater than 300 million gallons per year) can improve recovery efficiency because of the water-bankin

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

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2009-04-01

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

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

    USGS Publications Warehouse

    Galloway, Joel M.

    2004-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Andreo, B.; Mudarra, M.; Marin, A. I.; Barberá, J. A.

    2012-12-01

    The hydrogeological functioning and response of karst aquifers can be determined by the joint use of natural hydrogeochemical tracers, especially total organic carbon (TOC) and intrinsic fluorescence of water, together with artificial (fluorescent) tracers, under the same hydrodynamic conditions. Sharp and rapid variations in discharge, temperature, electrical conductivity and water chemistry, particularly of natural tracers of infiltration (TOC, intrinsic fluorescence and NO3-) recorded in karst spring water, confirm the existence of well developed karst conduits in the sector of the aquifer being drained, with rapid flows and very short water transit times from the surface to the springs (Mudarra et al., 2011). This is in agreement with the evidence obtained from breakthrough curves of fluorescent dye tracers (uranine, eosine, etc.). However, time lags between maximum concentrations of natural (especially TOC and intrinsic fluorescence) and artificial tracers show that the global system response is faster than that produced from a recharge concentrated at a point on the surface, even in karst sinkholes. Response and transit times of water through the karst can be calculated using both natural and artificial tracers, but flow velocities can really only be quantified using artificial tracers. Analysis of the responses obtained by natural tracers of infiltration (global system response) and artificial tracers (single response) in karst waters has revealed the usefulness and complementarity of both techniques for characterising the hydrogeological functioning of karst aquifers and, even more important, for validating contamination vulnerability mapping in these medium (Zwahlen, 2004; Andreo et al., 2006). In recent decades, several methods have been developed for such vulnerability mapping, but little progress has been made in validating their results. This validation is essential for the adequate protection of water resources in karst media, as has been shown in recent research (Marin et al., 2012; Ravbar et al., 2012). References: Andreo B, Goldscheider N, Vadillo I, Vías JM, Neukum C, Sinreich M, Jiménez P, Brechenmacher J, Carrasco F, Hötzl H, Perles MJ, Zwahlen F (2006a): Karst groundwater protection: First application of a Pan-European Approach to vulnerability, hazard and risk mapping in the Sierra de Líbar (Southern Spain). Science of the Total Environment, 357 1-3: 54-73. Marín AI, Andreo B and Dörfliger N (2012): Comparative application of two methods (COP and PaPRIKa) for groundwater vulnerability mapping in Mediterranean karst aquifers (France and Spain). Environmental Earth Sciences, 65: 2407-2421. Mudarra M, Andreo B and Baker A (2011): Characterisation of dissolved organic matter in karst spring waters using intrinsic fluorescence: Relationship with infiltration processes. Science of Total Environment, 40: 3448-3462. Ravbar N, Barberá JA, Petric M, Kogovsek J and Andreo B (2012): Study of hydrodynamic behaviour of a complex karst system under low-flow conditions using natural and artificial tracers (springs of the Unica River, SW Slovenia Environmental Earth Sciences, 65: 2259-2272. Zwahlen F -Editor- (2004). Vulnerability and risk mapping for the protection of carbonate (karst) aquifers, final report (COST action 620). - European Commission, Directorate-General XII Science, Research and Development: 297 pp.

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

    USGS Publications Warehouse

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

    2002-01-01

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

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

    USGS Publications Warehouse

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

    2000-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Brenčič, Mihael; Vreča, Polona

    2015-04-01

    Mapping is important part of the hydrogeological terrain investigations, especially when spatial and temporal relations are not known precisely. There are many different methods available; among them not least important is careful visual inspection of the stream and its stream bed at regular intervals with the aim to detect phenomena which reflect surface water groundwater interactions. In parallel with the inspection various measurements can be performed. Together with usual water electro conductivity and water temperature we tested complimentary information which can be obtained with the concomitant regular sampling for δ18O determination in the river water course. Combination of all these information proved to be very useful in obtaining spatial trends in river characteristics and to determine relations between its water balance components. Testing of the methodology of hydrogeological mapping with the means of isotopes on the karstic Savica River during low flow period where water balance relations between its tributaries were not known before demonstrate the usefulness of the applied approach. Savica River is positioned in the north-west part of Slovenia in the centre of Triglav national Park which covers large part of East Julian Alps. River represents the main recharge of the Bohinj Lake, largest Slovenian natural lake. Savica River is short with the length of only 4.0 km and consists of two tributaries in the upper part; Mala Savica coming from the west and Velika Savica coming from the north-west. The first is recharged from several water caves of various lengths in which water level depends on hydrological conditions, consequently terminal end of the water in its riverbed part changes during the year. The second tributary is recharged from the 510 m long karstic cave with the entrance at 836 m a.s.l. where water disappears over 75 m high famous and picturesque waterfall. Geology of the catchment is predominantly formed by Dachstein limestone of Upper Triassic age subordinated by small number of dolomite beds. In the period between years 1954 and 2012 was average discharge at the gauging station Savica Ukanc 5.08 m3/s. At the gauging profile riverbed is occasionally reported as dry and maximum measured discharge was 138 m3/s. Based on the three sampling campaigns performed at low water conditions when each time between 35 and 40 samples were taken, we were able to estimate relations between various Savica River components. During low water period Mala Savica defined presents between 12 % and 17 % of the total outflow from the total Savica recharge area. Velika Savica in its complete water course represents between 78 % and 82 % of the total outflow. There is also small part recharging in the area between the confluence of Velika Savica and Mala Savica and confluence of Savica with Bohinj Lake; this part represents from 3 % to 5 %, however estimations are very rough and probably prone to large error. Estimated relations are based on the rough calculations but represent important step forward in the understanding of complex Savica River system. Until now no data was available on the amount and share of Velika Savica and Mala Savica to the total outflow from the vast karstic recharge area on high mountainous plateau. Mapping campaigns along the whole river were performed at low to moderate hydrological conditions; therefore results cannot be transferred to the all possible hydrological conditions. However, similar results obtained during three seasons with slightly different discharge regimes indicate that the spatial relations are relatively stable. Results are important for further investigations of Savica River system. Such information can help to discern hydrogeologicaly important points along the river course and based on them we can focus on more detailed observations at particular sites. In the future they will help us in better understanding of hydrograph components and better understanding of the functioning of karstic aquifer draining through Savica springs and direct inflows of groundwater into the riverbed.

  14. Reef and nonreef aquifers - A comparison of hydrogeology and geochemistry, northwestern Indiana

    USGS Publications Warehouse

    Schnoebelen, D.J.; Krothe, N.C.

    1999-01-01

    The principal bedrock aquifer system across much of Indiana consists of carbonate rocks of Silurian and Devonian age. The Silurian-Devonian aquifer system is used extensively for irrigation in northwestern Indiana and is approximately 170 m thick. Reef and nonreef carbonate aquifers in northwestern Indiana were assessed using hydrogeology (lithology, geophysical logs, aquifer tests) and geochemistry (major ions and stable isotopes). The study showed differences in water quantity and quality between the reef and nonreef aquifers. The reef aquifer had few shales, abundant fossiliferous material (up to 100 m thick), and high porosities (10 to 15%). The nonreef aquifer had abundant shales, less fossiliferous material (a few meters thick), and low porosities. Total transmissivities at the reef sites were 697 m2/d, (meters squared per day) and 4831 m2/d, compared to 46 m2/d at the nonreef site. Flowpaths in the nonreef aquifer were associated with fractures and poorly connected moldic porosity with larger fractures and better connected vuggy porosity in the reef aquifer. Water chemistry data for the nonreef aquifer showed mean concentrations of sodium (235 mg/L [milligrams per liter]), sulfate (160 mg/L), sulfide (13 mg/L), fluoride (2.7 mg/L), and dissolved solids (635 mg/L) approximately two to five times larger when compared to mean concentrations in the reef aquifer. Ground water at the nonreef site was classified as a sodium-bicarbonate type while that at the reef sites was calcium-magnesium bicarbonate. The oxygen/deuterium isotope data indicates recharge from modern precipitation and not Pleistocene-age recharge.The principal bedrock aquifer system across much of Indiana consists of carbonate rocks of Silurian and Devonian age. The Silurian-Devonian aquifer system is used extensively for irrigation in northwestern Indiana and is approximately 170 m thick. Reef and nonreef carbonate aquifers in northwestern Indiana were assessed using hydrogeology (lithology, geophysical logs, aquifer tests) and geochemistry (major ions and stable isotopes). The study showed differences in water quantity and quality between the reef and nonreef aquifers. The reef aquifer had few shales, abundant fossiliferous material (up to 100 m thick), and high porosities (10 to 15%). The nonreef aquifer had abundant shales, less fossiliferous material (a few meters thick), and low porosities. Total transmissivities at the reef sites were 697 m2/d, (meters squared per day) and 4831 m2/d, compared to 46 m2/d at the nonreef site. Flowpaths in the nonreef aquifer were associated with fractures and poorly connected moldic porosity with larger fractures and better connected vuggy porosity in the reef aquifer. Water chemistry data for the nonreef aquifer showed mean concentrations of sodium (235 mg/L [milligrams per liter]), sulfate (160 mg/L), sulfide (13 mg/L), fluoride (2.7 mg/L), and dissolved solids (635 mg/L) approximately two to five times larger when compared to mean concentrations in the reef aquifer. Ground water at the nonreef site was classified as a sodium-bicarbonate type while that at the reef sites was calcium-magnesium bicarbonate. The oxygen/deuterium isotope data indicates recharge from modern precipitation and not Pleistocene-age recharge.

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

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

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

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

    USGS Publications Warehouse

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

    2000-01-01

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

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

    SciTech Connect

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

    2002-11-19

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

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

    SciTech Connect

    Lance Prothro, Sigmund Drellack, Margaret Townsend

    2009-03-25

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

  19. Constraining age distributions of groundwater from public supply wells in diverse hydrogeological settings in Scania, Sweden

    NASA Astrophysics Data System (ADS)

    Åkesson, Maria; Suckow, Axel; Visser, Ate; Sültenfuβ, Jürgen; Laier, Troels; Purtschert, Roland; Sparrenbom, Charlotte J.

    2015-09-01

    Twenty-five public supply wells throughout the hydrogeologically diverse region of Scania, southern Sweden are subjected to environmental tracer analysis (3H-3He, 4He, CFCs, SF6 and for one well only also 85Kr and 39Ar) to study well and aquifer vulnerability and evaluate possibilities of groundwater age distribution assessment. We find CFC and SF6 concentrations well above solubility equilibrium with modern atmosphere, indicating local contamination, as well as indications of CFC degradation. The tracer-specific complications considerably constrain possibilities for sound quantitative regional groundwater age distribution assessments and demonstrate the importance of initial qualitative assessment of tracer-specific reliability, as well a need for additional, complementary tracers (e.g. 85Kr, 39Ar and potentially also 14C). Lumped parameter modelling yields credible age distribution assessments for representative wells in four type aquifers. Pollution vulnerability of the aquifer types was based on the selected LPM models and qualitative age characterisation. Most vulnerable are unconfined dual porosity and fractured bedrock aquifers, due to a large component of very young groundwater. Unconfined sedimentary aquifers are vulnerable due to young groundwater and a small pre-modern component. Less vulnerable are semi-confined sedimentary or dual-porosity aquifers, due to older age of the modern component and a larger pre-modern component. Confined aquifers appear least vulnerable, due an entirely pre-modern groundwater age distribution (recharged before 1963). Tracer complications aside, environmental tracer analyses and lumped parameter modelling aid in vulnerability assessment and protection of regional groundwater resources.

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

    SciTech Connect

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

    2000-06-01

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

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

    USGS Publications Warehouse

    Rebich, Richard A.

    1994-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

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

    SciTech Connect

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

    1995-09-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

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

    USGS Publications Warehouse

    Grannemann, N.G.

    1984-01-01

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

  6. Palaeo-hydrogeology of the Cretaceous Sediments of the Williston Basin using Stable Isotopes of Water

    NASA Astrophysics Data System (ADS)

    Hendry, Michael J.; Barbour, S. Lee; Novakowski, Kent; Wassenaar, Len I.

    2013-04-01

    Hydraulic and isotopic data collected from aquifers are typically used to characterize hydrogeological conditions within sedimentary basins. Similar data from confining units are generally not collected despite their ability to provide insights into important water/solute transport controls. In this study, we characterized palaeo-groundwater flow and solute transport mechanisms across 384 m of a Cretaceous shale aquitard in the Williston Basin, Canada, using high-resolution depth profiles of water isotopes (δ18O and δ2H). Water samples were also collected from wells installed in the underlying regional aquifer (Mannville Fm; 93 m thick) and from seepage inflows into potash mine shafts (to 825 m below ground). 1-D numerical transport modeling of isotopic profiles yielded insight into large-scale/long-term solute transport in both Cretaceous sediments and the Basin. Molecular diffusion was determined to be the dominant solute transport mechanism through the aquitard. Transport model simulations suggest average vertical groundwater velocities of <0.05 m/10 ka and an average excess hydraulic head of <10 m. These values are less than anticipated by successive glaciations. The dominant palaeo-event reflected in present-day profiles is introduction during the Pleistocene of glaciogenic meteoric water to the aquifer underlying the aquitard, likely along an aquifer outcrop area east of the site or through local vertical conduits in the aquitard. Simulations suggest these recharge events occurred during one or more glacial periods. The isotopic profile over the upper 25 m of Pleistocene till and shale is consistent with glacial deposition and transport processes within these units during the Holocene (past 10 ka).

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

    PubMed

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

    2013-01-01

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

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

    USGS Publications Warehouse

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

    2013-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2005-12-01

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

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

    USGS Publications Warehouse

    Becker, C.J.

    1998-01-01

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

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

    USGS Publications Warehouse

    Reynolds, Richard J.

    2000-01-01

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

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

    USGS Publications Warehouse

    Stringfield, W.J.

    1994-01-01

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

  15. Hydrogeology and ground-water-quality conditions at the Emporia- Lyon County Landfill, eastern Kansas, 1988

    USGS Publications Warehouse

    Myers, N.C.; Bigsby, P.R.

    1990-01-01

    Hydrogeology and water-quality conditions at the Emporia-Lyon County Landfill, eastern Kansas, were investigated from April 1988 through April 1989. Potentiometric-surface maps indicated groundwater movement from the northeast and northwest towards the landfill and then south through the landfill to the Cottonwood River. The maps indicate that during periods of low groundwater levels, groundwater flows northward in the north-west part of the landfill, which may have been induced by water withdrawal from wells north of the landfill or by water ponded in waste lagoons south and west of the landfill. Chemical analysis of water samples from monitoring wells upgradient and downgradient of the landfill indicate calcium bicarbonate to be the dominant water type. No inorganic or organic chemical concentrations exceeded Kansas or Federal primary drinking-water standards. Kansas secondary drinking-water standards were equaled or exceeded, however, in water from some or all wells for total hardness, dissolved solids, iron, and manganese. Water from one upgradient well contained larger concentrations of dissolved oxygen and nitrate, and smaller concentrations of bicarbonate, alkalinity, ammonia, arsenic, iron, and manganese as compared to all other monitoring wells. Results of this investigation indicate that groundwater quality downgradient of well MW-2 has increased concentrations of some inorganic and organic compounds. Due to the industrial nature of the area and the changing directions of groundwater flow, it is not clear what the source of these compounds might be. Long-term monitoring, additional wells, and access to nearby waste lagoons and waste-lagoon monitoring wells would help define the sources of increased inorganic and organic compounds. (USGS)

  16. Hydrogeologic conditions and water management modeling for a Sierra Nevada fen wetland

    NASA Astrophysics Data System (ADS)

    Ronayne, M. J.; Cooper, D.; Wolf, E. C.

    2012-12-01

    Small fens occur throughout the Sierra Nevada, providing carbon storage and critical habitat for plant and animal species. The accumulated peat within fens, which has distinct physical and hydraulic properties, plays an important role in the hydrologic function of these wetland systems. In this study, we investigated the hydrogeology of a 0.5-ha fen in Yosemite National Park using hydraulic head data, stable isotope analysis, and numerical modeling. Peat thickness within the fen ranges from less than 10 cm to 1.4 m. Saturated conditions are produced by convergent groundwater flow originating from two distinct source areas. Water levels throughout the fen and surrounding meadow vary seasonally and interannually in response to natural variability in precipitation. The water table position is also influenced by pumping from a deep water supply well, which extracts groundwater from a weathered bedrock zone that is hydraulically connected to the surficial sediments. A spatially distributed 3D numerical groundwater model was developed to assess the relative importance of precipitation and groundwater pumping in controlling the water table position. The model results indicate that groundwater pumping has a significant impact on shallow water levels during a year with below-average precipitation. In a representative dry year, existing groundwater pumping accounts for approximately two-thirds of the water table decline (> 1 m) that is observed during June through September. During a wet year characterized by high winter/spring precipitation, there is sufficient water in storage to maintain saturated conditions throughout the summer. Predictive modeling was performed to evaluate alternative groundwater-use scenarios. These results will be used to develop water management strategies that support wetland stability.

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

    USGS Publications Warehouse

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

    1997-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

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

    SciTech Connect

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

    1994-04-01

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

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

    NASA Astrophysics Data System (ADS)

    Ritzi, Robert W.; Bobeck, Patricia

    2008-10-01

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

  1. Hydrogeology and quality of ground water on Guemes Island, Skagit County, Washington

    USGS Publications Warehouse

    Kahle, S.C.; Olsen, T.D.

    1995-01-01

    Guemes Island, located in Puget Sound of Washington State, is experiencing population growth and seawater intrusion. The island consists of Pleistocene glacial deposits overlying bedrock. Geologic sections and a map of surficial geology were constructed and used to delineate six hydrogeologic units, three of which are aquifers. The most productive aquifer is the Double Bluff aquifer, situated at or below sea level. Water budget estimates indicate that of the 21-29 inches of precipitation received in a typical year, 0-4 inches runs off, 12-22 inches evapotranspires, and 2-10 inches recharges the ground-water system. Of the water recharged, 0.1-0.3 inches is withdrawn by wells; the remainder recharges deeper aquifer(s) or discharges from the ground-water system to drainage ditches or the sea. The median dissolved-solids concentration was 236 mg/L (milligrams per liter). Half of the samples were classified as moderately hard, the remainder as hard or very hard. Although magnesium-calcium/bicarbonate water types dominate, some samples contained large amounts of sodium and chloride. The median concentration of 0.08 mg/L for nitrate indicates that no widespread contamination from septic systems or livestock exists. Small concentrations of arsenic were present in 5 of 24 samples. Trace concentrations of volatile organic compounds were detected in three of five samples. None of the U.S. Environmental Protection Agency's maximum contaminant levels was exceeded. However, secondary maximum contaminant levels were exceeded for dissolved solids, chloride, manganese, and iron. Seasonal variability of chloride concentration was apparent in water from coastal wells that had chloride concentrations greater than 100 mg/L. Higher values occurred from April through September because of increased pumping and lower recharge.

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

    NASA Astrophysics Data System (ADS)

    Alcolea, Andres; Renard, Philippe

    2010-08-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

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

    USGS Publications Warehouse

    Westjohn, David B.; Hoard, Chris J.

    2006-01-01

    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-water samples were collected and analyzed for major ions, nutrients, and trace-metal composition. In addition, 10 direct current-resistivity soundings were collected throughout Chippewa and Coe Townships to identify potential freshwater in the aquifer system. The aquifer system includes complexly interbedded glaciofluvial, glaciolacustrine, and basal-lodgment tills, which overlie Jurassic or Pennsylvanian sedimentary rocks. In parts of the township, freshwater is present in all geologic units, but in most areas saline water is encountered near the base of Pleistocene glacial deposits and in the Jurassic or Pennsylvanian bedrock. A near-surface sheet of relatively dense basal-lodgment till likely prevents, or substantially retards, significant direct recharge of ground water to glacial and bedrock aquifers in Chippewa and adjacent townships. Glacial sands and gravels form the principal aquifer for domestic wells (97.5 percent of wells in the township). The single community water supply in the township has wells screened in glacial deposits near the base of the glacial drift. Increased withdrawals of ground water in response to increasing demand has led to a slight decline in water quality from this supply. This water-quality decline is related primarily to an increase of dissolved sulfate, which is probably a function of well depth and dissolution of gypsum, a common mineral constituent in the Jurassic 'red beds,' which form the uppermost bedrock unit throughout most of the township. One explanation for the increase in sulfate is upconing of saline water from bedrock sources, which may contain saline water.

  5. Groundwater intensive use and mining in south-eastern peninsular Spain: Hydrogeological, economic and social aspects.

    PubMed

    Custodio, Emilio; Andreu-Rodes, José Miguel; Aragón, Ramón; Estrela, Teodoro; Ferrer, Javier; García-Aróstegui, José Luis; Manzano, Marisol; Rodríguez-Hernández, Luis; Sahuquillo, Andrés; Del Villar, Alberto

    2016-07-15

    Intensive groundwater development is a common circumstance in semiarid and arid areas. Often abstraction exceeds recharge, thus continuously depleting reserves. There is groundwater mining when the recovery of aquifer reserves needs more than 50years. The MASE project has been carried out to compile what is known about Spain and specifically about the south-eastern Iberian Peninsula and the Canary Islands. The objective was the synthetic analysis of available data on the hydrological, economic, managerial, social, and ethical aspects of groundwater mining. Since the mid-20th century, intensive use of groundwater in south-eastern Spain allowed extending and securing the areas with traditional surface water irrigation of cash crops and their extension to former dry lands, taking advantage of good soils and climate. This fostered a huge economic and social development. Intensive agriculture is a main activity, although tourism plays currently an increasing economic role in the coasts. Many aquifers are relatively high yielding small carbonate units where the total groundwater level drawdown may currently exceed 300m. Groundwater storage depletion is estimated about 15km(3). This volume is close to the total contribution of the Tagus-Segura water transfer, but without large investments paid for with public funds. Seawater desalination complements urban supply and part of cash crop cultivation. Reclaimed urban waste water is used for irrigation. Groundwater mining produces benefits but associated to sometimes serious economic, administrative, legal and environmental problems. The use of an exhaustible vital resource raises ethical concerns. It cannot continue under the current legal conditions. A progressive change of water use paradigm is the way out, but this is not in the mind of most water managers and politicians. The positive and negative results observed in south-eastern Spain may help to analyse other areas under similar hydrogeological conditions in a less advanced stage of water use evolution. PMID:27065448

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

    NASA Astrophysics Data System (ADS)

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

    2004-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

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

    NASA Astrophysics Data System (ADS)

    Re, Viviana

    2015-11-01

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

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

    NASA Astrophysics Data System (ADS)

    Ahmed, Izrar; Umar, Rashid

    2008-02-01

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

  11. Advancements and Applications of Low-Field NMR for Characterizing and Monitoring Hydrogeologic Properties in the Saturated and Unsaturated Zones

    NASA Astrophysics Data System (ADS)

    Grunewald, E. D.; Walsh, D. O.

    2014-12-01

    Geophysical NMR measurements allow direct quantification of fluid content and estimation of critical flow and storage parameters, including bound/mobile porosity, pore size, and permeability. Following widespread adoption of NMR logging in the oilfield, novel low-field NMR technologies have been developed for measuring groundwater and hydrogeologic properties in the near-surface. Adaptation and optimization of these technologies has been required to meet the unique objectives of near-surface investigations. Here we present recent technical enhancements to low-field NMR instrumentation and methodologies along with field results from hydrogeologic characterization and monitoring applications. Improvements to circuit design have led to a significant reduction of the NMR echo-time, yielding more accurate detection and quantification of signals with short T2 (i.e. associ