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At least 595 records · Page 33Linked to original sources

Hydrogeologic mapping and three-dimensional geologic modeling of glacial deposits in a multicounty area of southeastern Michigan, northeastern Indiana, and northwestern Ohio

The glacial deposits underlying southeastern Michigan, northeastern Indiana, and northwestern Ohio are a substantial source of water to communities, agriculture, and industry in the region. Previous efforts to characterize aquifer materials in the area cited a need for additional information about the underlying hydrogeologic characteristics and related groundwater availability as well as improved mapping of the extent and properties of the glacial deposits. Recent U.S. Geological Survey multi-State compilations of water-well drilling records have greatly increased access to high-resolution geologic data, particularly in glacial depositional environments. This study by the U.S. Geological Survey, in cooperation with the Ohio Environmental Protection Agency, uses processed data from the State-managed collections of well records to characterize the glacial deposits in the study area using two methods. The first method creates two-dimensional maps of basic hydrogeologic information commonly required for assessments of groundwater availability, including (1) total thickness of glacial deposits, (2) total thickness of coarse-grained deposits, (3) specific-capacity-based transmissivity and hydraulic conductivity, and (4) texture-based estimated equivalent horizontal and vertical hydraulic conductivity and transmissivity. The second method builds a hydrogeologic framework of the complex glacial aquifer through construction of a volumetric geologic model by using three-dimensional kriging. Results of the volumetric model indicate that aquifer materials are primarily concentrated in the western parts of the study area near the Indiana-Ohio border. Coarse-grained sediments are also present as surficial deposits in the north of the study area where intermixing glacial advances created complex distributions of unconsolidated deposits. Two-dimensional maps of hydrogeologic properties support the volumetric model, showing thicknesses of coarse-grained deposits that reach up to 250 feet in the western sections of the study area and progressively thin to near absence in the east. Visualization of the aquifer materials with a volumetric model generally shows a highly discontinuous distribution of coarse- and fine-grained materials, with no clearly defined boundaries to delineate the extent of the aquifer. Comparisons of cross sections derived from the volumetric model with existing published maps support previous near-surface hydrogeologic interpretations while filling gaps where data are sparse, particularly in deeper parts of the aquifer. Both the two-dimensional maps and the volumetric model provide data that can directly inform assessments of groundwater availability, in addition to having future applications to studies of groundwater flow and transport.

Indiana, Michigan, Ohio↗

Groundwater-quality and quality-control data for two monitoring wells near Pavillion, Wyoming, April and May 2012

In June 2010, the U.S. Environmental Protection Agency installed two deep monitoring wells (MW01 and MW02) near Pavillion, Wyoming, to study groundwater quality. During April and May 2012, the U.S Geological Survey, in cooperation with the Wyoming Department of Environmental Quality, collected groundwater-quality data and quality-control data from monitoring well MW01 and, following well redevelopment, quality-control data for monitoring well MW02. Two groundwater-quality samples were collected from well MW01—one sample was collected after purging about 1.5 borehole volumes, and a second sample was collected after purging 3 borehole volumes. Both samples were collected and processed using methods designed to minimize atmospheric contamination or changes to water chemistry. Groundwater-quality samples were analyzed for field water-quality properties (water temperature, pH, specific conductance, dissolved oxygen, oxidation potential); inorganic constituents including naturally occurring radioactive compounds (radon, radium-226 and radium-228); organic constituents; dissolved gasses; stable isotopes of methane, water, and dissolved inorganic carbon; and environmental tracers (carbon-14, chlorofluorocarbons, sulfur hexafluoride, tritium, helium, neon, argon, krypton, xenon, and the ratio of helium-3 to helium-4). Quality-control sample results associated with well MW01 were evaluated to determine the extent to which environmental sample analytical results were affected by bias and to evaluate the variability inherent to sample collection and laboratory analyses. Field documentation, environmental data, and quality-control data for activities that occurred at the two monitoring wells during April and May 2012 are presented.

Wyoming↗

Groundwater quality and geochemistry of West Virginia’s southern coal fields

Coal mining has been the dominant industry and land use in West Virginia’s southern coal fields since the mid-1800s. Mortality rates for a variety of serious chronic conditions, such as diabetes, heart disease, and some forms of cancer in Appalachian coal mining regions, are higher than in areas lacking substantial coal mining activity within the Appalachian Region or elsewhere in the United States. Causes of the increased mortality and morbidity are not clear, but poor diet, high rates of smoking, socioeconomic factors, and the quality of groundwater used by area residents are all possible contributing factors. This study was conducted by the U.S. Geological Survey in cooperation with the West Virginia Department of Health and Human Resources and the West Virginia Department of Environmental Protection, with grant support from the Centers for Disease Control and Prevention (CDC) to assess the quality of groundwater in southern West Virginia. The data from this assessment of groundwater quality may be used by the CDC and other agencies to potentially investigate the role or lack thereof of groundwater quality with respect to mortality and morbidity rates in the region. The study was conducted in a region where a high density of current or past coal mining combined with a lack of advanced sewage treatment could affect concentrations of commonly occurring constituents plus contaminants, including nitrate, trace metals, major ions, indicator bacteria, radon, hydrogen sulfide, and dissolved hydrocarbons. Because rural residential wells and mine outfalls are considered private sources of water in the region, and are therefore unregulated and unmonitored, water-quality data are sparse. To fill the data gap and assess the groundwater quality in the region, water-quality samples were collected from 60 sites in a 10-county area. The 60 sites sampled included 46 rural residential homeowner wells and 14 mine outfall discharges used for residential supply. For this study, all samples were collected prior to any filtration or other treatments, typically at the pressure tank, and are indicative of total and dissolved constituents in the untreated water. Generally, data for the 60 sites indicate that most waters sampled do not exceed thresholds for most U.S. Environmental Protection Agency (EPA) drinking-water standards and U.S. Geological Survey (USGS) drinking-water screening criteria. However, there were several notable exceptions. Turbidity exceeded the 5-Nephelometric Turbidity Unit (NTU) EPA treatment technique (TT) drinking-water standard in 14 of 60 (23 percent) sites sampled and exceeded the 1-NTU TT standard in 51 of 60 (85 percent) sites sampled. Turbidity is common in many wells in southern West Virginia and may be attributed to iron oxyhydroxide precipitates, sediment carried into the aquifers from the shallow soil zone due to improperly constructed or cased wells or transported to the aquifer in shallow stress-relief fracture zones or through permeable bedding-plane partings. For the sites sampled, 31 of 60 (52 percent) had pH values at, above, or below the upper and lower range of the EPA Secondary Maximum Contaminant Level (SMCL, 6.5–8.5 standard units). Of those 31 sites, 28 (90 percent) were indicative of acidic corrosive water and 3 (10 percent) were indicative of alkaline water. The Langelier Saturation Index (LSI), which is a measure of the corrosivity of the water, was computed for all sites sampled for the study. Eighty-two percent of the sites sampled had waters that were classified as corrosive, based on a LSI less than −0.5. Corrosive water has the potential to leach lead, copper, and other metals from lead, copper, galvanized, or lead-tin soldered connections in water lines. The chloride to sulfate mass ratio also was assessed with the alkalinity to indicate the potential to promote galvanic corrosion (PPGC) of water lines and plumbing fixtures. Only one of the sites (1.7 percent) classified as a corrosive water site, had a PPGC considered high; the remaining sites were classified as having either a moderate (53.3 percent) or low (45 percent) PPGC. Therefore, the type of plumbing systems sampled for this study may be affected by corrosive water, but the potential for leaching trace metals and other constituents from residential plumbing systems containing older galvanized pipes or lead-tin soldered copper pipes is moderate to low. The indicator bacteria total coliform and Escherichia coli ( E. coli ) also were detected in groundwater samples to varying degrees. Total coliforms, which are a broad class of indicator bacteria, are common in groundwater in southern West Virginia and were detected in 39 of the 60 sites (65 percent) sampled. The presence of total coliform bacteria is a potential indicator of surface contamination, due to improperly constructed or cased wells, or infiltration of soil or other surface contaminants into the aquifer or well bore. E. coli bacteria, however, are much more indicative of fecal contamination of groundwater from either human or animal sources, and 14 of the 60 (23 percent) sites sampled had detections of E. coli . Although only a few strains of E. coli are known pathogens, their presence in groundwater may be an indicator of other related pathogens such as viruses and should be regarded as a serious potential issue. Water treatment such as chlorination, ozonation, or ultraviolet light may be appropriate to kill potential pathogenic bacteria or viruses in the source water. Manganese and iron were prevalent contaminants in the groundwater samples collected for this study, with 30 of 60 (50 percent) sites analyzed for manganese and 25 of 60 (42 percent) sites analyzed for iron exceeding the proposed 50- and 300-micrograms per liter (µg/L) SMCL drinking-water standards, respectively, for aesthetic criteria such as taste, odor, or staining of plumbing fixtures. Fourteen of the 60 sites sampled (23 percent) had concentrations of manganese that exceeded the 300-µg/L USGS health-based screening level, and 1 site exceeded the 1,600-µg/L EPA drinking-water equivalent level, which is based on a lifetime exposure level. Sodium is another common constituent in groundwater within the study area. Sodium has an EPA health-based value (HBV) of 20 milligrams per liter (mg/L) for individuals who are on a sodium-restricted diet for blood pressure or other health reasons. Sodium concentrations exceeded the 20-mg/L EPA HBV in 27 of 60 (45 percent) samples. Radon, a naturally occurring carcinogenic radioactive gas known to cause lung cancer, was detected at concentrations at or exceeding the proposed 300-picocuries per liter (pCi/L) EPA Maximum Contaminant Level (MCL) in 12 of the 60 (20 percent) sites sampled. Sites with radon gas concentrations exceeding the 300-pCi/L proposed MCL have the potential for airborne concentrations of radon to exceed the 4-pCi/L indoor air standard. Inhalation of radon can cause lung cancer, and the 4-pCi/L indoor air standard is based on an inhalation standard. Therefore, homeowners whose wells have radon gas concentrations exceeding 300 pCi/L may be advised to have their indoor air tested to determine if indoor air concentrations exceed the 4-pCi/L indoor air standard established by the EPA. Various factors were analyzed statistically and graphically to determine whether they have an influence on groundwater quality within the study area, including topographic setting, well depth, type of mining (surface or underground), type of site (well or mine outfall), and geologic formation. Only geologic formation and the type of site sampled had strong statistical correlations with one or more of the constituents of concern for this study. The overall chemistry of outfalls (mine outfalls) and wells was significantly different, with a much higher dissolved oxygen content in outfalls than in wells. The dissolved oxygen content is the primary component driving the oxidation and reduction of minerals, and the precipitation of minerals that are saturated or super saturated with respect to various cations and anions. Median dissolved oxygen concentrations for the outfalls sampled was 8.75 mg/L, and only 0.4 mg/L for the wells sampled. Median concentrations of sulfate and selenium were much higher in waters from the outfalls sampled, with median concentrations of 73.75 mg/L and 2.35 µg/L, respectively, compared to the wells sampled, which had median concentrations of 18.3 mg/L and less than (<) the 0.05-µg/L method detection limit, respectively. The maximum selenium concentration was for a well, with a concentration of 16.6 µg/L. The geochemical processes that control sulfate and selenium concentrations in groundwater are similar and are the result of the oxidation of sulfide minerals such as pyrite and ferroselite. Iron and manganese concentrations were elevated in most of the wells sampled, with median concentrations of 269.5 and 124.5 µg/L, respectively, but were rarely detected in the outfalls sampled, with median concentrations of < 4.0 and < 0.4 µg/L, respectively. The difference in iron and manganese between wells and outfalls is indicative of the role of dissolved oxygen on processes controlling groundwater chemistry in the region. Three principal geologic formations were assessed for the study, and the overall chemistry for the Pocahontas, New River, and Kanawha Formations varied substantially with respect to several constituents. Concentrations of calcium, magnesium, and total dissolved solids were highest for sites sampled in the Pocahontas Formation, with median concentrations of 41.9, 18.6, and 312 mg/L, respectively. For constituents that are commonly associated with mining activity, the highest concentrations were for sites sampled in the New River Formation, with median concentrations of iron and manganese of 2,450 µg/L and 482 µg/L, respectively, and a median pH of 6.35 standard units. Concentrations of barium also were elevated in samples collected from sites in the New River Formation, with a median barium concentration of 184 µg/L. The source of the barium is not fully known but may be associated with commingling of shallow groundwater with deeper brines or dissolution of the mineral barite. The highest median sulfate concentrations were from sites sampled in the Pocahontas Formation, with a median concentration of 64.0 mg/L. Of the 12 sites at or exceeding the 300-pCi/L proposed drinking-water standard for radon, 8 (67 percent of MCL exceedances) were for sites deriving water from the Kanawha Formation, 3 (25 percent of MCL exceedances) were for sites deriving water from the New River Formation, and only 1 site was for water from the Pocahontas Formation (8 percent of proposed MCL exceedances). Dissolved hydrocarbons, including methane, ethane, propane, propene, n - and i -butane, 1-butene, n - and i -pentane, pentane, 2- and 3-ethyl pentane, hexane, and benzene were analyzed in samples collected from 59 of the 60 sites to assess the potential occurrence and sources of these trace gases in groundwater within the study area. Results of the analysis indicate that most of the gas is of shallow biogenic origin, possibly associated with coal-bed methane, but a subset of samples has a gas signature and a chloride to bromide ratio indicative of potential mixing with deeper thermogenic gases. Only 2 of the 59 (3.3 percent) sites sampled had concentrations of methane gas, which is a highly combustible and explosive gas, exceeding the 10 milligrams per kilogram level of concern established by the U.S. Office of Surface Mining Reclamation and Enforcement. Principal components analysis was used to assess the primary geochemical processes occurring in the aquifers sampled. The first principal component had significant positive loadings for bromide, chloride, silica, ammonia, barium, iron, manganese, and arsenic, and significant negative loadings for dissolved oxygen, potassium, nitrate, and uranium, and reflects reduction and oxidation (redox) processes occurring in deeper anoxic groundwater or shallow oxic groundwater. The strong positive loadings for iron, manganese, barium, and arsenic are correlated with reducing conditions often found deeper in the aquifer. More oxic water is correlated with oxidation of nitrogen species to nitrate and environmental mobilization of uranium and sulfate in shallow wells and mine outfalls.

West Virginia↗

A multi-metric assessment of environmental contaminant exposure and effects in an urbanized reach of the Charles River near Watertown, Massachusetts

The Charles River Project provided an opportunity to simultaneously deploy a combination of biomonitoring techniques routinely used by the U.S. Geological Survey National Water Quality Assessment Program, the Biomonitoring of Environmental Status and Trends Project, and the Contaminant Biology Program at an urban site suspected to be contaminated with polycyclic aromatic hydrocarbons. In addition to these standardized methods, additional techniques were used to further elucidate contaminant exposure and potential impacts of exposure on biota. The purpose of the study was to generate a comprehensive, multi-metric data set to support assessment of contaminant exposure and effects at the site. Furthermore, the data set could be assessed to determine the relative performance of the standardized method suites typically used by the National Water Quality Assessment Program and the Biomonitoring of Environmental Status and Trends Project, as well as the additional biomonitoring methods used in the study to demonstrate ecological effects of contaminant exposure. The Contaminant Effects Workgroup, an advisory committee of the U.S. Geological Survey/Contaminant Biology Program, identified polycyclic aromatic hydrocarbons as the contaminant class of greatest concern in urban streams of all sizes. The reach of the Charles River near Watertown, Massachusetts, was selected as the site for this study based on the suspected presence of polycyclic aromatic hydrocarbon contamination and the presence of common carp ( Cyprinus carpio ), largemouth bass ( Micropterus salmoides ), and white sucker ( Catostomus commersoni ). All of these fish have extensive contaminant-exposure profiles related to polycyclic aromatic hydrocarbons and other environmental contaminants. This project represented a collaboration of universities, Department of the Interior bureaus including multiple components of the USGS (Biological Resources Discipline and Water Resources Discipline Science Centers, the Contaminant Biology Program, and the Status and Trends of Biological Resources Program), and the U.S. Fish and Wildlife Service. Samples for analyzing water chemistry, sediment chemistry and toxicity, fish community structure, tissue chemistry, and fish (20 carp, 20 bass, and 40 white sucker) and invertebrate pathology were collected in late August, 2005. This report provides results from the analyses of fish pathology, biomarkers of exposure and effects (reproductive, carcinogenic, genotoxic, and immunologic), sediment chemistry, toxicity, and fish and invertebrate community structure.

Massachusetts↗

Areal studies aid protection of ground-water quality in Illinois, Indiana, and Wisconsin

In 1991, the U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, initiated studies designed to characterize the ground-water quality and hydrogeology in northern Illinois, and southern and eastern Wisconsin (with a focus on the north-central Illinois cities of Belvidere and Rockford, and the Calumet region of northeastern Illinois and northwestern Indiana). These areas are considered especially susceptible to ground-water contamination because of the high density of industrial and waste-disposal sites and the shallow depth to the unconsolidated sand and gravel aquifers and the fractured, carbonate bedrock aquifers that underlie the areas. The data and conceptual models of ground-water flow and contaminant distribution and movement developed as part of the studies have allowed Federal, State, and local agencies to better manage, protect, and restore the water supplies of the areas. Water-quality, hydrologic, geologic, and geophysical data collected as part of these areal studies indicate that industrial contaminants are present locally in the aquifers underlying the areas. Most of the contaminants, particularly those at concentrations that exceeded regulatory water-quality levels, were detected in the sand and gravel aquifers near industrial or waste-disposal sites. In water from water-supply wells, the contaminants that were present generally were at concentrations below regulatory levels. The organic compounds detected most frequently at concentrations near or above regulatory levels varied by area. Trichloroethene, tetrachloroethene, and 1,1,1-trichloroethane (volatile chlorinated compounds) were most prevalent in north-central Illinois; benzene (a petroleum-related compound) was most prevalent in the Calumet region. Differences in the type of organic compounds that were detected in each area likely reflect differences in the types of industrial sites that predominate in the areas. Nickel and aluminum were the trace metals detected most frequently at concentrations above regulatory levels in both areas. Contaminants in the shallow sand and gravel aquifers and carbonate aquifers appear to have moved with ground water discharging to local lakes, streams, and wetlands. Ground-water flow and possibly contaminant movement is concentrated in the weathered surface zones and in deeper fractures of the carbonate aquifers underlying both areas.

Illinois, Indiana, Wisconsin↗

Publications of Western Earth Surface Processes Team 2001

The Western Earth Surface Processes Team (WESPT) of the U.S. Geological Survey (USGS) conducts geologic mapping and related topical earth-science studies in the Western United States. This work is focused on areas where modern geologic maps and associated earth-science data are needed to address key societal and environmental issues, such as ground-water quality, landslides and other potential geologic hazards, and land-use decisions. Areas of primary emphasis in 2001 included southern California, the San Francisco Bay region, the Pacific Northwest, and the Las Vegas urban corridor. The team has its headquarters in Menlo Park, California, and maintains smaller field offices at several other locations in the Western United States. The results of research conducted by the WESPT are released to the public as a variety of databases, maps, text reports, and abstracts, both through the internal publication system of the USGS and in diverse external publications such as scientific journals and books. This report lists publications of the WESPT released in 2001, as well as additional 1999 and 2000 publications that were not included in the previous list (USGS Open-File Report 00–215 and USGS Open-File Report 01–198). Most of the publications listed were authored or coauthored by WESPT staff. The list also includes some publications authored by non-USGS cooperators with the WESPT, as well as some authored by USGS staff outside the WESPT in cooperation with WESPT projects. Several of the publications listed are available on the World Wide Web; for these, URL addresses are provided. Many of these web publications are USGS Open-File Reports that contain large digital databases of geologic map and related information.

Open-File Report↗

Publications of the Western Earth Surface Processes Team 2002

The Western Earth Surface Processes Team (WESPT) of the U.S. Geological Survey (USGS) conducts geologic mapping and related topical earth science studies in the western United States. This work is focused on areas where modern geologic maps and associated earth-science data are needed to address key societal and environmental issues such as ground-water quality, landslides and other potential geologic hazards, and land-use decisions. Areas of primary emphasis in 2001 included southern California, the San Francisco Bay region, the Pacific Northwest, and the Las Vegas urban corridor. The team has its headquarters in Menlo Park, California, and maintains smaller field offices at several other locations in the western United States. The results of research conducted by the WESPT are released to the public as a variety of databases, maps, text reports, and abstracts, both through the internal publication system of the USGS and in diverse external publications such as scientific journals and books. This report lists publications of the WESPT released in 2002 as well as additional 1998 and 2001 publications that were not included in the previous list (USGS Open-File Report 00-215, USGS Open-File Report 01-198, and USGS Open-File Report 02-269). Most of the publications listed were authored or coauthored by WESPT staff. The list also includes some publications authored by non-USGS cooperators with the WESPT, as well as some authored by USGS staff outside the WESPT in cooperation with WESPT projects. Several of the publications listed are available on the World Wide Web; for these, URL addresses are provided. Many of these web publications are USGS open-file reports that contain large digital databases of geologic map and related information. Information on ordering USGS publications can be found on the World Wide Web or by calling 1-888-ASK-USGS. The U.S. Geological Survey’s web server for geologic information in the western United States is located at http://geology.wr.usgs.gov. More information is available about the WESPT is available on-line at the team website.

Open-File Report↗

Publications of the Western Earth Surfaces Processes Team 2005

Introduction The Western Earth Surface Processes Team (WESPT) of the U.S. Geological Survey (USGS) conducts geologic mapping, earth-surface process investigations, and related topical earth science studies in the western United States. This work is focused on areas where modern geologic maps and associated earth-science data are needed to address key societal and environmental issues such as ground-water quality, landslides and other potential geologic hazards, and land-use decisions. Areas of primary emphasis in 2005 included southern California, the San Francisco Bay region, the Mojave Desert, the Colorado Plateau region of northern Arizona, and the Pacific Northwest. The team has its headquarters in Menlo Park, California, and maintains smaller field offices at several other locations in the western United States. The results of research conducted by the WESPT are released to the public as a variety of databases, maps, text reports, and abstracts, both through the internal publication system of the USGS and in diverse external publications such as scientific journals and books. This report lists publications of the WESPT released in 2005 as well as additional 2002, 2003, and 2004 publications that were not included in the previous lists (USGS Open-File Reports 03-363, 2004- 1267, 2005-1362). Most of the publications listed were authored or coauthored by WESPT staff. The list also includes some publications authored by non-USGS cooperators with the WESPT, as well as some authored by USGS staff outside the WESPT in cooperation with WESPT projects. Several of the publications listed are available on the World Wide Web; for these, URL addresses are provided. Many of these web publications are USGS Open-File reports that contain large digital databases of geologic map and related information. Information on ordering USGS publications can be found on the World Wide Web at http://www.usgs.gov/pubprod/, or by calling 1-888-ASK-USGS. The U.S. Geological Survey's web server for geologic information in the western United States is located at http://geology.wr.usgs.gov/. More information is available about the WESPT is available on-line at http://geology.wr.usgs.gov/wgmt.

Open-File Report↗

Publications of the Western Earth Surface Processes Team 2006

The Western Earth Surface Processes Team (WESPT) of the U.S. Geological Survey (USGS) conducts geologic mapping, earth-surface process investigations, and related topical earth science studies in the western United States. This work is focused on areas where modern geologic maps and associated earth-science data are needed to address key societal and environmental issues such as ground-water quality, landslides and other potential geologic hazards, and land-use decisions. Areas of primary emphasis in 2006 included southern California, the San Francisco Bay region, the Mojave Desert, the Colorado Plateau region of northern Arizona, and the Pacific Northwest. The team has its headquarters in Menlo Park, California, and maintains smaller field offices at several other locations in the western United States. This compilation gives the bibliographical citations for 123 new publications, most of which are available online using the hyperlinks provided.

Open-File Report↗

National coal resource assessment non-proprietary data: Location, stratigraphy, and coal quality for selected tertiary coal in the Northern Rocky Mountains and Great Plains region

One of the objectives of the National Coal Resource Assessment in the Northern Rocky Mountains and Great Plains region was to compile stratigraphic and coal quality-trace-element data on selected and potentially minable coal beds and zones of the Fort Union Formation (Paleocene) and equivalent formations. In order to implement this objective, drill-hole information was compiled from hard-copy and digital files of the: (1) U.S. Bureau of Land Management (BLM) offices in Casper, Rawlins, and Rock Springs, Wyoming, and in Billings, Montana, (2) State geological surveys of Montana, North Dakota, and Wyoming, (3) Wyoming Department of Environmental Quality in Cheyenne, (4) U.S. Office of Surface Mining in Denver, Colorado, (5) U.S. Geological Survey, National Coal Resource Data System (NCRDS) in Reston, Virginia, (6) U.S. Geological Survey coal publications, (7) university theses, and (8) mining companies.

Open-File Report↗

Altitude, depth, and thickness of the Galena-Platteville Bedrock Unit in the subcrop area of Illinois and Wisconsin

The Galena-Platteville bedrock unit is a carbonate deposit of Ordovician age, composed of the Galena and Platteville Groups in Illinois and the Sinnippee Group in Wisconsin. It is the uppermost bedrock unit (subcrop) in most of northern Illinois and southern and eastern Wisconsin. The subcrop area is shaded in figure 1 of sheet 1 (Batten and others, 1997). The unit is predominately dolomite, with limestone in some areas, and has a weathered surface. Across the subcrop area, the hydrologic characteristics of the bedrock unit vary substantially. The bedrock unit may be either a confining unit or an aquifer. In areas where the Galena-Platteville bedrock unit is an aquifer, the unit is a dependable source of water for many private wells and some municipal-water-supply systems. Ground water in the Galena-Platteville bedrock aquifer is susceptible to contamination because the bedrock unit is near land surface in much of the study area, and the fractures in the unit allow rapid movement of water providing limited capacity to attenuate contaminants. The subcrop (study) area covers approximately 7,850 square miles in northern Illinois and Wisconsin. In the study area, volatile organic compounds and other contaminants have been detected in the aquifer at various sites (Mills, 1993; Kay and others, 1994). Many sources of contaminants, including landfills and industrial facilities, are known or suspected. In order to determine the possible effects of contamination on the ground-water supply, an understanding of the regional hydrogeologic framework of the Galena-Platteville bedrock unit is needed. Published and unpublished map and point data describing the geologic properties of the Galena-Platteville bedrock unit are available from many sources. The U.S. Geological Survey (USGS), in cooperation with the U.S. Environmental Protection Agency (USEPA), has selected and compiled a large portion of the available data to create computer data bases and maps. The objective of this effort is to compile and publish these data in a series of reports (U.S. Geological Survey Water-Resources Investigations Reports (WRIR) 974054-A, WRIR 97-4054-B, WRIR 97-4054-C). This is the third in that series of reports. The report describes the altitude, thickness, and depth from land surface of the subcrop area of the Galena-Platteville bedrock unit. The report series will enable investigators involved in site-specific studies within the subcrop area to understand the regional geologic framework of the unit and to find additional reference sources. This report consists of four sheets that show the altitude (sheet 1), depth from land surface (sheet 2), total thickness (sheet 3), and location of altitude data (sheet 4) of the lithologic units that constitute the Galena-Platteville bedrock unit within the subcrop area. The sheets also show major known geologic features within the Galena-Platteville study area in Illinois and Wisconsin. A geographic information system (GIS) was used to generate data layers (coverages) from point data and from published and unpublished contour maps at various scales and detail. Standard GIS procedures were used to change the coverages into the maps shown on the sheets presented in this report. A list of references for the data used to prepare the maps is provided.

Illinois, Wisconsin↗

Rock-stratigraphic nomenclature, lithology, and subcrop area of the Galena-Platteville bedrock unit in Illinois and Wisconsin

The Galena-Platteville bedrock unit is a dependable source of ground water for many private well owners and some municipal-water-supply systems in northern Illinois (Hackett, 1960) and in Wisconsin. The carbonate lithology of the unit contributes to the availability of ground water and also to the susceptibility of the unit to ground-water contamination. Susceptibility to contamination is greatest in areas where the unit is overlain by only a thin layer (less than 50 feet) of soil or unconsolidated glacial deposits. Within the study area in Illinois and Wisconsin (fig. 1), volatile organic compounds and other contaminants have been detected in groundwater samples from various sites (Kay and others, 1989; Mills, 1993a, 1993b; Kay and others, 1994). Known and suspected sources of contaminants are numerous, including landfills and industrial facilities. To determine the possible effects of contamination on the ground-water supply, an understanding of the regional hydrogeologic framework of the Galena-Platteville bedrock unit is needed. Published map and point data describing the geologic and hydrologic properties of the Galena-Platteville bedrock unit are available from many sources. The U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, Region 5, has selected and compiled pertinent data. The objective of this study is to publish these data in a series of concise map reports and a bibliographic report listing available sources of information by county for the Galena-Platteville bedrock unit. Investigators involved in site-specific studies within the subcrop area will be able to utilize these reports to design effective site investigations. This report presents the rock-stratigraphic nomenclature of the lithologic units that make up the Galena-Platteville bedrock unit (fig.2) and provides a brief, generalized description of the lithologic characteristics of each unit. Sources with more detailed descriptions of lithology can be found below in SELECTED REFERENCES. Figure 3 is a map, created from published maps of various scales, showing the areal extent of the Galena-Platteville subcrop and major known geologic structural features in Illinois and Wisconsin. The subcrop area of the Galena-Platteville bedrock unit is that area where the unit crops out, or is the uppermost bedrock unit and is overlain by soil or glacial deposits. The unit is present at depth under younger bedrock units south and east of the subcrop area and is absent north and west of the subcrop area. Data sources used to prepare the map are included in SELECTED REFERENCES.

Illinois, Wisconsin↗

Potential for increased inundation in flood-prone regions of southeast Florida in response to climate and sea-level changes in Broward County, Florida, 2060–69

The U.S. Geological Survey, in cooperation with Broward County Environmental Planning and Resilience Division, has developed county-scale and local-scale groundwater/surface-water models to study the potential for increased inundation and flooding in eastern Broward County that are due to changes in future climate and sea-level rise. These models were constructed by using MODFLOW 2005, with the surface-water system represented by using the Surface-Water Routing process and a new Urban Runoff process. The local-scale model allowed the use of finer grid resolution in a selected area of the county, whereas the county-scale model provided boundary conditions for the local-scale model and insight into the hydrologic behavior of the larger system. The aquifer layering, properties, and boundaries relied heavily on a previous three-dimensional variable-density solute-transport model of the same area developed by the U.S. Geological Survey. The surface-water system within these new models actively simulates a part of the extensive canal network by using level-pool routing and active structure operations within the Surface-Water Routing process. These models were used to simulate a historical base-case period (1990–99) by using measured data and regional climate model rainfall and potential evapotranspiration output. The simulated flow and water-level results generally captured the behavior of the hydrologic system. A future period (2060–69) was simulated by using regional climate model rainfall and potential evapotranspiration output representing a wetter and drier future and low, intermediate, and high sea-level rise projections. The results were used to evaluate the potential effects on the surface-water drainage system, coastal-structure operation, and wet-season groundwater levels. Future period simulations using the county-scale model indicate that (1) the effects of the changing climate and sea level are much more evident in eastern and coastal areas of Broward County compared to western areas, with increases in groundwater level nearly equivalent to sea-level rise; (2) coastal groundwater-level increases are distributed farther inland in the wetter future scenarios than in the drier future scenarios; (3) water levels at the westernmost groundwater station locations exhibited little change caused by sea-level rise and showed more dependence on changes in precipitation; (4) there was a reduced west-to-east groundwater gradient with increasing sea-level rise; and (5) increased downstream tidal stage at the S–13 structure resulted in increased reliance on the pump to control upstream inland canal stages. Future simulations using the local-scale model indicate similar behavior as seen in the county-scale model: (1) the coastal areas exhibited the largest impacts in groundwater levels in the future scenarios; (2) the westernmost, interior areas exhibited little change during the future scenarios; and (3) there was an increased reliance on the pump at the S–13 coastal structure but to a lesser extent than indicated in the county-scale model because of the reduced temporal scale of the local-scale model. Possible adaptation and mitigation strategies were simulated to evaluate the county-scale and local-scale models’ ability to simulate hydrologic changes. Alterations to S–13 pump operations within the county-scale model were tested, and results indicate a reduced effect of sea-level rise inland of the control structure, but the affected area is spatially limited. The concept of using pumps to reduce the local groundwater levels in two neighborhood-sized areas was tested by using the local-scale model. The MODFLOW 2005 Drain package was used to remove groundwater by using drainage elevations set to zero, 1 foot, and 2 feet above average wet-season groundwater levels. Area 1 was well connected to coastal boundaries, and a high rate of groundwater removal was required, whereas the rate of groundwater removal required was greatly reduced in Area 2, which is less connected to tidal boundaries. Water for these scenarios was assumed to be pumped to tide with no downstream effects.

Florida↗

Ecoregions of Arizona (poster)

Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and quantity of environmental resources; they are designed to serve as a spatial framework for the research, assessment, management, and monitoring of ecosystems and ecosystem components. By recognizing the spatial differences in the capacities and potentials of ecosystems, ecoregions stratify the environment by its probable response to disturbance. These general purpose regions are critical for structuring and implementing ecosystem management strategies across federal agencies, state agencies, and nongovernment organizations that are responsible for different types of resources within the same geographical areas. The Arizona ecoregion map was compiled at a scale of 1:250,000. It revises and subdivides an earlier national ecoregion map that was originally compiled at a smaller scale. The approach used to compile this map is based on the premise that ecological regions can be identified through the analysis of the spatial patterns and the composition of biotic and abiotic phenomena that affect or reflect differences in ecosystem quality and integrity. These phenomena include geology, physiography, vegetation, climate, soils, land use, wildlife, and hydrology. The relative importance of each characteristic varies from one ecological region to another regardless of the hierarchical level. A Roman numeral hierarchical scheme has been adopted for different levels of ecological regions. Level I is the coarsest level, dividing North America into 15 ecological regions. Level II divides the continent into 50 regions. At level III, the continental United States contains 105 ecoregions and the conterminous United States has 85 ecoregions. Level IV is a further subdivision of level III ecoregions. Arizona contains arid deserts and canyonlands, semiarid shrub- and grass-covered plains, woodland- and shrubland-covered hills, lava fields and volcanic plateaus, forested mountains, glaciated peaks, and river alluvial floodplains. Ecological diversity is remarkably high. There are 7 level III ecoregions and 52 level IV ecoregions in Arizona and many continue into ecologically similar parts of adjacent states. This poster is part of a collaborative project primarily between the U.S. Geological Survey (USGS), USEPA National Health and Environmental Effects Research Laboratory (Corvallis, Oregon), USEPA Region IX, U.S. Department of Agriculture (USDA)–Natural Resources Conservation Service (NRCS), The Nature Conservancy, and several Arizona state agencies. The project is associated with an interagency effort to develop a common national framework of ecological regions. Reaching that objective requires recognition of the differences in the conceptual approaches and mapping methodologies applied to develop the most common ecoregion-type frameworks, including those developed by the USDA–Forest Service, the USEPA, and the NRCS. As each of these frameworks is further refined, their differences are becoming less discernible. Collaborative ecoregion projects, such as this one in Arizona, are a step toward attaining consensus and consistency in ecoregion frameworks for the entire nation.

Arizona↗

Aquifer tests and simulation of ground-water flow in Triassic sedimentary rocks near Colmar, Bucks and Montgomery Counties, Pennsylvania

This report presents the results of a study by the U.S. Geological Survey in cooperation with the U.S. Environmental Protection Agency to evaluate ground-water flow in Triassic sedimentary rocks near Colmar, in Bucks and Montgomery Counties, Pa. The study was conducted to help the U.S. Environmental Protection Agency evaluate remediation alternatives at the North Penn Area 5 Superfund Site near Colmar, where ground water has been contaminated by volatile organic solvents (primarily trichloroethene). The investigation focused on determining the (1) drawdown caused by separately pumping North PennWater Authority wells NP–21 and NP–87, (2) probable paths of groundwater movement under present-day (2000) conditions (with NP–21 discontinued), and (3) areas contributing recharge to wells if pumping from wells NP-21 or NP–87 were restarted and new recovery wells were installed. Drawdown was calculated from water levels measured in observation wells during aquifer tests of NP–21 and NP–87. The direction of ground-water flow was estimated by use of a three-dimensional ground-water-flow model. Aquifer tests were conducted by pumping NP–21 for about 7 days at 257 gallons per minute in June 2000 and NP–87 for 3 days at 402 gallons per minute in May 2002. Drawdown was measured in 45 observation wells during the NP–21 test and 35 observation wells during the NP–87 test. Drawdown in observation wells ranged from 0 to 6.8 feet at the end of the NP–21 test and 0.5 to 12 feet at the end of the NP–87 test. The aquifer tests showed that ground-water levels declined mostly in observation wells that were completed in the geologic units penetrated by the pumped wells. Because the geologic units dip about 27 degrees to the northwest, shallow wells up dip to the southeast of the pumped well showed a good hydraulic connection to the geologic units stressed by pumping. Most observation wells down dip from the pumping well penetrated units higher in the stratigraphic section that were not well connected to the units stressed by pumping. The best hydraulic connection to the pumped wells was indicated by large drawdown in observation wells that penetrate the water-bearing unit encountered below 400 feet below land surface in wells NP–21 and NP–87. The hydraulic connection between wells NP–21 (or NP–87) and observation wells in the southern area of ground-water contamination near the BAE Systems facility is good because the observation wells probably penetrate this water-bearing unit. A 3-dimensional, finite-difference, groundwater- flow model was used to simulate flow paths and areas contributing recharge to wells for current (2000) conditions of pumping in the Colmar area and for hypothetical situations of pumping suggested by the U.S. Environmental Protection Agency that might be used for remediation. Simulations indicate that under current conditions, ground water in the northern area of contamination near the former Stabilus facility moves to the northwest and discharges mostly to West Branch Neshaminy Creek; in the southern area of contamination near BAE Systems facility, ground water probably moves west and discharges to a tributary of West Branch Neshaminy Creek near well NP–21. Model simulations indicate that if NP–21 or NP–87 are pumped at 400 gallons per minute, groundwater recharge is likely captured from the southern area of contamination, but ground-water recharge from the northern area of contamination is less likely to be captured by the pumping. Simulations also indicate that pumping of a new recovery well near BAE Systems facility at 8 gallons per minute and two new recovery wells near the former Stabilus facility at a total of about 30 gallons per minute probably would capture most of the ground-water recharge in the areas where contamination is greatest.

Water-Resources Investigations Report↗

High-resolution geologic mapping of the inner continental shelf: Nahant to Gloucester, Massachusetts

This report presents high-resolution maps of the seafloor offshore of Massachusetts, from Nahant to Gloucester. Approximately 134 km² of the inner shelf were mapped with a focus on the nearshore region in water depths less than 40 m (fig. 1.1). The maps were prepared as part of a cooperative mapping program between the U.S. Geological Survey (USGS) and the Massachusetts Office of Coastal Zone Management (CZM). They are based on marine geophysical data, sediment sampling, and bottom photography obtained on two research cruises carried out in 2003 and 2004. The primary objective of this program is to develop a suite of seafloor maps that provide geologic information for management of coastal and marine resources. Accurate maps of seafloor geology are important first steps toward protecting fish habitat, delineating marine reserves, and assessing environmental changes due to natural or human impacts. The maps also provide a geologic framework for scientific research, industry and the public. The organization of this report is outlined in the navigation bar along the left-hand margin of the page. This is section 1, the introduction. Section 2 briefly describes the mapping products contained in this report and has links to large-format map sheets, that can be viewed on line or downloaded. Section 3 is a description of the data collection, processing, and analysis procedures used to create the map products. Section 4 examines the geologic framework and late Quaternary evolution of the region, and presents two different strategies for mapping the complex seafloor. This report also contains four appendices that include GIS layers of all data collected in this study, and copies of the sample and photographic data used to validate the interpretations.

Massachusetts↗

Preliminary preview for a geographic and monitoring program project; a review of point source-nonpoint source effluent trading/offset systems in watersheds

Watershed-based trading and offset systems are being developed to improve policy-maker?s and regulator?s ability to assess nonpoint source impacts in watersheds and to evaluate the efficacy of using market-incentive programs for preserving environmental quality. An overview of the history of successful and failed trading programs throughout the United States suggests that certain political, economic, and scientific conditions within a temporal and spatial setting help meet water quality standards. The current lack of spontaneous trading among dischargers does not mean that a marketable permit trading system is an inherently inefficient regulatory approach. Rather, its infrequent use is the result of institutional and informational barriers. Improving and refining the earth science information and technologies may help determine whether trading is a suitable policy for improving water quality. However, it is debatable whether or not environmental information is the limiting factor. This paper reviews additional factors affecting the potential for instituting a trading policy. The motivation for investigating and reviewing the history of offsets and trading was inspired by a project in the preliminary stages being developed by U.S. Geological Survey Western Geographic Science Center and the Environmental Protection Agency Region IX. An offset feasibility study will be an integrated, map-based approach that incorporates environmental, economic, and statistical information to investigate the potential for using offsets to meet mercury Total Maximum Daily Loads in the Sacramento River watershed. A regional water-quality offset program is being studied that may help known point sources reduce mercury loading more cost effectively by the remediation of abandoned mines or other diffuse sources as opposed to more costly treatment at their own sites. An efficient offset program requires both a scientific basis and methods to translate that science into a regulatory decision framework.

Open-File Report↗

Physical, Hydrological, and Biological Characteristics of the Loxahatchee River Estuary, Florida

The Loxahatchee River estuary empties into the Atlantic Ocean at Jupiter Inlet in southeastern Florida. Although relatively small, the estuary is important for its esthetic value and for its sport fishing, boating, recreation, tourism, and prime residential development. In recent years, the condition of the estuary has become of concern to many citizens and agencies of the State. In response to this concern, the U.S. Geological Survey planned and carried out an in-depth environmental investigation. The events that led to the investigation and the objectives of the investigation are outlined in a recent U.S. Geological Survey report by McPherson and Sabanskas (WRI 80-1109).

Water-Resources Investigations Report↗