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Ground-Water Quality and Potential Effects of Individual Sewage Disposal System Effluent on Ground-Water Quality in Park County, Colorado, 2001-2004

In 2000, the U.S. Geological Survey, in cooperation with Park County, Colorado, began a study to evaluate ground-water quality in the various aquifers in Park County that supply water to domestic wells. The focus of this study was to identify and describe the principal natural and human factors that affect ground-water quality. In addition, the potential effects of individual sewage disposal system (ISDS) effluent on ground-water quality were evaluated. Ground-water samples were collected from domestic water-supply wells from July 2001 through October 2004 in the alluvial, crystalline-rock, sedimentary-rock, and volcanic-rock aquifers to assess general ground-water quality and effects of ISDS's on ground-water quality throughout Park County. Samples were analyzed for physical properties, major ions, nutrients, bacteria, and boron; and selected samples also were analyzed for dissolved organic carbon, human-related (wastewater) compounds, trace elements, radionuclides, and age-dating constituents (tritium and chlorofluorocarbons). Drinking-water quality is adequate for domestic use throughout Park County with a few exceptions. Only about 3 percent of wells had concentrations of fluoride, nitrate, and (or) uranium that exceeded U.S. Environmental Protection Agency national, primary drinking-water standards. These primary drinking-water standards were exceeded only in wells completed in the crystalline-rock aquifers in eastern Park County. Escherichia coli bacteria were detected in one well near Guffey, and total coliform bacteria were detected in about 11 percent of wells sampled throughout the county. The highest total coliform concentrations were measured southeast of the city of Jefferson and west of Tarryall Reservoir. Secondary drinking-water standards were exceeded more frequently. About 19 percent of wells had concentrations of one or more constituents (pH, chloride, fluoride, sulfate, and dissolved solids) that exceeded secondary drinking-water standards. Currently (2004), there is no federally enforced drinking-water standard for radon in public water-supply systems, but proposed regulations suggest a maximum contaminant level of 300 picocuries per liter (pCi/L) and an alternative maximum contaminant level of 4,000 pCi/L contingent on other mitigating remedial activities to reduce radon levels in indoor air. Radon concentrations in about 91 percent of ground-water samples were greater than or equal to 300 pCi/L, and about 25 percent had radon concentrations greater than or equal to 4,000 pCi/L. Generally, the highest radon concentrations were measured in samples collected from wells completed in the crystalline-rock aquifers. Analyses of ground-water-quality data indicate that recharge from ISDS effluent has affected some local ground-water systems in Park County. Because roughly 90 percent of domestic water used is assumed to be recharged by ISDS's, detections of human-related (wastewater) compounds in ground water in Park County are not surprising; however, concentrations of constituents associated with ISDS effluent generally are low (concentrations near the laboratory reporting levels). Thirty-eight different organic wastewater compounds were detected in 46 percent of ground-water samples, and the number of compounds detected per sample ranged from 1 to 17 compounds. Samples collected from wells with detections of wastewater compounds also had significantly higher (p-value < 0.05) chloride and boron concentrations than samples from wells with no detections of wastewater compounds. ISDS density (average subdivision lot size used to estimate ISDS density) was related to ground-water quality in Park County. Chloride and boron concentrations were significantly higher in ground-water samples collected from wells located in areas that had average subdivision lot sizes of less than 1 acre than in areas that had average subdivision lot sizes greater than or equal to 1 acre. For wells completed in the crystalline-

Scientific Investigations Report↗

Summary of the U.S. Geological Survey and U.S. Bureau of Land Management national coal-hydrology program, 1974-84

During the decade 1974-84, the U.S. Geological Survey and the U.S. Bureau of Land Management cooperated on investigations to collect information and to study hydrologic processes related to development and mining of federally owned coal. In addition, the U.S. Geological Survey conducted similar investigations related to nonfederally owned coal. As a result of these nationwide investigations, a large quantity of hydrologic information and data has been collected and compiled in more than 500 reports. This report summarizes the major findings and accomplishments that have resulted from data-collection activities, hydrologic studies, and research concerned with the effects of coal mining on water resources. This summary report includes: (1) A description of the Nation's coal and water-resource issues related to coal development, including history, objectives, and design of the coal-hydrology program; (2) a summary of the hydrologic information collected in the major coal provinces and published in more than 500 reports and journal articles; and (3) a summary and application of results obtained from topical studies undertaken throughout the program, including discussions on watershed modeling, salinity modeling, ground-water flow systems, geochemistry of mine spoils, mine drainage, sedimentation, and aquatic biology. A detailed coal-hydrology reference list concludes the report.

continental United States↗

MODFLOW-2000, the U.S. Geological Survey modular ground-water model -- Documentation of the Model-Layer Variable-Direction Horizontal Anisotropy (LVDA) capability of the Hydrogeologic-Unit Flow (HUF) package

This report documents the model-layer variable-direction horizontal anisotropy (LVDA) capability of the Hydrogeologic-Unit Flow (HUF) Package of MODFLOW-2000. The LVDA capability allows the principal directions of horizontal anisotropy to be different than the model-grid row and column directions, and for the directions to vary on a cell-by-cell basis within model layers. The HUF Package calculates effective hydraulic properties for model grid cells based on hydraulic properties of hydrogeologic units with thicknesses defined independently of the model layers. These hydraulic properties include, among other characteristics, hydraulic conductivity and a horizontal anisotropy ratio. Using the LVDA capability, horizontal anisotropy direction is defined for model grid cells within which one or more hydrogeologic units may occur. For each grid cell, the HUF Package calculates the effective horizontal hydraulic conductivity along the primary direction of anisotropy using the hydrogeologic-unit hydraulic conductivities, and calculates the effective horizontal hydraulic conductivity along the orthogonal anisotropy direction using the effective primary direction hydraulic conductivities and horizontal anisotropy ratios. The direction assigned to the model layer effective primary hydraulic conductivity is specified using a new data set defined by the LVDA capability, when active, to calculate coefficients needed to solve the ground-water flow equation. Use of the LVDA capability is illustrated in four simulation examples, which also serve to verify hydraulic heads, advective-travel paths, and sensitivities calculated using the LVDA capability. This version of the LVDA capability defines variable-direction horizontal anisotropy using model layers, not the hydrogeologic units defined by the HUF Package. This difference needs to be taken into account when designing model layers and hydrogeologic units to produce simulations that accurately represent a given field problem. This might be a reason, for example, to make model layer boundaries coincide with hydrogeologic-unit boundaries in all or part of a model grid.

Open-File Report↗

Thermal profiles for selected river reaches in the Stillaguamish River basin, Washington, August 2011

Datums Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83). Abstract Longitudinal profiles of near-streambed temperature were collected for eight river reaches in the Stillaguamish River basin, Washington, during August 2011, to provide information about areas of groundwater discharge to streams. During summer, groundwater discharge can be a source of cold water to streams that regulates warm stream temperatures creating cold-water thermal refugia for native stream biota including salmon and trout. To assess areas of groundwater discharge to streams, temperature was measured using a probe with an internal datalogger towed behind a watercraft moving downstream at ambient stream velocity. The data were referenced to location, concurrently surveyed with a Global Positioning System, during collection of the water temperature data. Data are presented as Microsoft Excel&reg; files consisting of date and time, near-streambed water temperature, and latitude and longitude. Introduction Longitudinal profiles of near-streambed temperatures surveyed at ambient river velocity in a Lagrangian framework provide information about potential areas of groundwater discharge as well as salmonid habitat and thermal refugia (Vaccaro and Maloy, 2006). Longitudinal thermal profiles have previously been surveyed in several rivers in Washington, including the Yakima River and tributaries (Vaccaro and others, 2008) and the Nooksack River (Cox and others, 2005). This report presents eight thermal profiles within the Stillaguamish River basin including parts of the North Fork Stillaguamish River, South Fork Stillaguamish River, Jim Creek, and Pilchuck Creek (fig. 1). This data augments previous investigations of longitudinal temperature variations within the Stillaguamish River and tributaries by thermal infrared radar by the Washington State Department of Ecology (Watershed Sciences, 2002), and may be used as a tool to develop a better understanding of groundwater/surface-water interactions within the Stillaguamish River basin. Purpose and Scope The purpose of this report is to present longitudinal thermal profiles of stream temperature of streams within the Stillaguamish River basin including the North Fork Stillaguamish River, the South Fork Stillaguamish River, Pilchuck Creek, and Jim Creek. This data may be used to determine zones of groundwater discharge and improve understanding of the relation between the groundwater and surface water systems of the Stillaguamish River basin. Description of Study Area The Stillaguamish River basin is in northwestern Washington and is bounded to the east by the Cascade Mountains, to the west by Puget Sound, to the north by the Skagit River basin, and to the south by the Snohomish River basin (fig. 1). The Stillaguamish River basin is characterized by cool, wet winters and warm, dry summers. Mean annual discharge of the North Fork Stillaguamish River (North Fork Stillaguamish River near Arlington, Washington, USGS gaging station 12167000) for water years 1929-2010 is 1,898 ft 3 /s and mean annual discharge of the South Fork Stillaguamish River (South Fork Stillaguamish River near Granite Falls, Washington gaging station 12161000) for water years 1929-1980 is 1,071 ft 3 /s. Jim Creek is a tributary of the South Fork Stillaguamish River and Pilchuck Creek is a tributary of the mainstem Stillaguamish River. Thermal Profile Survey Continuous water temperature and Global Positioning System (GPS) data were collected at 3-second intervals while drifting downstream at ambient stream velocity in a Lagrangian framework following the method of Vaccaro and Maloy (2006) for Pilchuck Creek between river mile (RM) 0.0 and 3.7 (table 1); the North Fork Stillaguamish River between RM 0.0 and 34.2 (tables 2-5); South Fork Stillaguamish River between RM 17.7 and 33.4 (tables 6-7); and Jim Creek between RM 0.0 and 7.0 (table 8). Profiling at ambient stream velocity in a Lagrangian framework tracks a parcel of water as it moves downstream during the day; departures from the diurnal heating cycle may be due to groundwater input, surface-water inflows, or riparian shading. Continuous temperature was measured using a Solinst&reg; Levelogger LT temperature probe verified by a National Institute of Standards and Technology (NIST) certified thermistor and position data was measured using a Garmin&reg; GPSmap&reg; 60Csx for the eight surveys during August 15-26, 2011. The temperature probe was towed behind a watercraft following the stream thalweg and dragged along the streambed except when in-stream obstacles prevented probe movement downstream. The location of each temperature measurement was determined by relating the time stamp of the GPS data to the temperature data. If a GPS location was not recorded at the same time as a temperature measurement, the location of the temperature measurement was determined by linear interpolation of the two GPS known locations that bracket the time of the temperature measurement. A 0.5-mi gap exists between the beginning of the North Fork Stillaguamish datasets collected on August 18 (table 4) and August 22 (table 5) because of inadequate equilibration of the temperature probe to ambient stream temperature during the initial 0.5 mi of the August 22 survey. Distribution of Information An Excel file of tables 1-8 that include the thermal-profile data for each longitudinal thermal profile is available at http://pubs.usgs.gov/ds/654/ds654_tables.xls. Table 1. Temperature and Global Positioning System location data for the Pilchuck Creek (RM 0.0-3.7), August 15, 2011. Table 2. Temperature and Global Positioning System location data for the North Fork Stillaguamish River (RM 30.0-34.2), August 16, 2011. Table 3. Temperature and Global Positioning System location data for the North Fork Stillaguamish River (RM 17.6-30.0), August 17, 2011. Table 4. Temperature and Global Positioning System location data for the North Fork Stillaguamish River (RM 9.5-17.6), August 18, 2011. Table 5. Temperature and Global Positioning System location data for the North Fork Stillaguamish River (RM 0.0-9.0), August 22, 2011. Table 6. Temperature and Global Positioning System location data for the South Fork Stillaguamish River (RM 25.9-33.4), August 24, 2011. Table 7. Temperature and Global Positioning System location data for the South Fork Stillaguamish River (RM 17.7-25.9), August 26, 2011. Table 8. Temperature and Global Positioning System location data for Jim Creek (RM 0.0-7.0), August 25, 2011. References Cited Cox, S.E., Simonds, F.W., Doremus, L., Huffman, R.L., and Defawe, R.M., 2005, Ground water/surface water interactions and quality of discharging ground water in streams of the lower Nooksack River Basin, Whatcom County, Washington: U.S. Geological Survey Scientific Investigations Report 2005-5255, 46 p Vaccaro, J.J., Keys, M.E., Julich, R.J., and Welch, W.B., 2008, Thermal profiles for selected river reaches in the Yakima River basin, Washington: U.S. Geological Survey Data Series 342 (Available at http://pubs.usgs.gov/ds/342/). Vaccaro, J.J., and Maloy, K.J., 2006, A thermal profile method to identify potential ground-water discharge areas and preferred salmonid habitats for long river reaches: U.S. Geological Survey Scientific Investigations Report 2006-5136, 16 p. Watershed Sciences, LLC, 2002, Aerial surveys in the Stillaguamish and Skagit River Basins-Thermal infrared and color videography: Corvallis, Oreg., Water Sciences, for Washington Department of Ecology, 28 p.

Data Series↗

Ground-water conditions and studies in Georgia, 2001

The U.S. Geological Survey (USGS) collects ground-water data and conducts studies to monitor hydrologic conditions, to better define ground-water resources, and address problems related to water supply and water quality. Data collected as part of ground-water studies include geologic, geophysical, hydraulic property, water level, and water quality. A ground-water-level network has been established throughout most of the State of Georgia, and ground-water-quality networks have been established in the cities of Albany, Savannah, and Brunswick and in Camden County, Georgia. Ground-water levels are monitored continuously in a network of wells completed in major aquifers of the State. This network includes 17 wells in the surficial aquifer, 12 wells in the upper and lower Brunswick aquifers, 73 wells in the Upper Floridan aquifer, 10 wells in the Lower Floridan aquifer and underlying units, 12 wells in the Claiborne aquifer, 1 well in the Gordon aquifer, 11 wells in the Clayton aquifer, 11 wells in the Cretaceous aquifer system, 2 wells in Paleozoic-rock aquifers, and 7 wells in crystalline-rock aquifers. In this report, data from these 156 wells were evaluated to determine whether mean-annual ground-water levels were within, below, or above the normal range during 2001, based on summary statistics for the period of record. Information from these summaries indicates that water levels during 2001 were below normal in almost all aquifers monitored, largely reflecting climatic effects from drought and pumping. In addition, water-level hydrographs for selected wells indicate that water levels have declined during the past 5 years (since 1997) in almost all aquifers monitored, with water levels in some wells falling below historical lows. In addition to continuous water-level data, periodic measurements taken in 52 wells in the Camden County-Charlton County area, and 65 wells in the city of Albany-Dougherty County area were used to construct potentiometric-surface maps for the Upper Floridan aquifer. Ground-water quality in the Upper Floridan aquifer is monitored in the cities of Albany, Savannah, and Brunswick and in Camden County; and monitored in the Lower Floridan aquifer in the Savannah and Brunswick areas. In the Albany area since 1998, nitrate concentrations in the Upper Floridan aquifer have increased in 4 of the 11 wells monitored, and in 1 well, concentrations were above the U.S. Environmental Protection Agency's (USEPA) 10 milligrams per liter (mg/L) drinking-water standard. In the Savannah area, chloride concentration in water from four wells in the Upper Floridan aquifer showed no appreciable change during 2001, remaining within the USEPA 250 mg/L drinking-water standard; in seven wells completed in the Lower Floridan aquifer and in underlying zones, the chloride concentration remained above the drinking-water standard, with one well showing an increase over previous years. In the Brunswick area, water samples from 66 wells completed in the Upper or Lower Floridan aquifers were collected during June 2001 and analyzed for chloride. A map showing chloride concentrations in the Upper Floridan aquifer during June 2001 indicates that concentrations remained above USEPA drinking-water standards across a 2-square-mile area. In the north Brunswick area, chloride concentrations in the Upper Floridan aquifer continued to increase, whereas in the south Brunswick area, concentrations continued to decrease. In the Camden County area, chloride concentrations in six wells completed in the Upper Floridan aquifer remained within drinking-water standards. With the exception of one well, concentrations remained the same and were below 40 mg/L. In one well, concentrations showed a sharp decline during 2001, but remained above 130 mg/L. Ongoing studies during 2001 include evaluation of agricultural chemicals in shallow ground water in southwestern Georgia; evaluation of saltwater intrusion and water-level and water-quality m

Georgia↗

Spatial data for Eurycea salamander habitats associated With three aquifers in south-central Texas

Eurycea salamander taxa comprise 12 known species that inhabit springs and caves in south-central Texas. Many of these are threatened or endangered species, and some are found only at one location. A number of the neotenic salamanders might be at risk from habitat loss associated with declines in ground-water levels. Eurycea salamander habitats are associated with three aquifers in south-central Texas: (1) the Edwards-Trinity (Plateau) aquifer, (2) the Edwards (Balcones Fault Zone) aquifer, and (3) the Trinity aquifer. The Edwards (Balcones fault zone) aquifer is commonly separated into three segments: from southwest to northeast, the San Antonio segment, the Barton Springs segment, and the northern segment. The Trinity aquifer south of the Colorado River can be divided into three permeable zones, the upper, middle, and lower zone. The U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service, developed this report (geodatabase) to aggregate the spatial data necessary to assess the potential effects of ground-water declines on known Eurycea habitat locations in south-central Texas. The geodatabase provides information about spring habitats, spring flow, cave habitats, aquifers, and projected water levels.

Data Series↗

Water Resources Data for Oregon, Water Year 2002

The annual Oregon hydrologic data report is one of a series of annual reports that document hydrologic data gathered from the U.S. Geological Survey's surface- and ground-water data-collection networks in each State, Puerto Rico, and the Trust Territories. These records of streamflow, ground-water levels, and quality of water provide the hydrologic information needed by State, local and Federal agencies, and the private sector for developing and managing our Nation's land and water resources. This report includes records on both surface and ground water in the State and contains discharge records for 181 stream-gaging stations, 47 partial-record or miscellaneous streamflow stations, and 8 crest-stage partial-record streamflow stations; stage-only records for 6 gaging stations; stage and content records for 26 lakes and reservoirs; and water-quality records for 127 streamflow-gaging stations, 2 atmospheric deposition stations, and 11 ground-water sites.

Water Data Report↗

Water Resources Data for Oregon, Water Year 2003

The annual Oregon hydrologic data report is one of a series of annual reports that document hydrologic data gathered from the U.S. Geological Survey's surface- and ground-water data-collection networks in each State, Puerto Rico, and the Trust Territories. These records of streamflow, ground-water levels, and quality of water provide the hydrologic information needed by State, local and Federal agencies, and the private sector for developing and managing our Nation's land and water resources. This report includes records on both surface and ground water in Oregon and contains discharge records for 199 stream-gaging stations, 25 partial-record or miscellaneous streamflow stations, and 8 crest-stage partial-record streamflow stations; stage-only records for 6 gaging stations; stage and content records for 26 lakes and reservoirs; and water-quality records collected at 127 streamflow-gaging stations, 2 atmospheric deposition stations, and 11 ground-water sites.

Water Data Report↗

Map showing outcrops of basaltic rocks of early Quaternary and Tertiary age, Basin and Range province, Southern California

This map report is one of a series of geologic and hydrologic maps covering all or parts of States within the Basin and Range province of the western United States. The map reports contain detailed information on subjects that characterize the geohydrology of the province, including the ground-water hydrology/ ground-water quality, surface distribution of selected rock types, tectonic conditions, areal geophysics, Pleistocene lakes and marshes, and mineral and energy resources. This is a part of the U.S. Geological Survey's program for geologic and hydrologic evaluation of the province to identify prospective regions for further study relative to isolation of high-level nuclear waste (Bedinger, Sargent, and Reed, 1984). This map was prepared from published geologic maps and reports utilizing the project guidelines defined in Sargent and Bedinger (1984). As used in this study, basaltic rocks include basaltic andesite and basalt. The map shows the known occurrences of basaltic rocks largely of Tertiary age. Locally, however, where basalts of Quaternary age were not differentiated from those of Tertiary age, the younger basalts have been included on the map. The Description of Map Units includes the geologic and, if available, radiometric age; lithology; thickness where available; and sources of data for the basaltic units in outlined and numbered areas within the counties of the study area. No information was available on the rock outcrops that are unnumbered. The listed radiometric ages do not necessarily represent the entire age range of a unit.

California↗

Ground-water geology of the Bruneau–Grand View area, Owyhee County, Idaho

The Bruneau-Grand View area is part of an artesian basin in northern Owyhee County, Idaho. The area described in this report comprises about 600 square miles, largely of undeveloped public domain, much of which is open, or may be opened, for desert-entry filing. Many irrigation-entry applications to the Federal Government are pending, and information about ground-water geology is needed by local citizens and well drillers, by Federal agencies that have custody of the land, and by local and State agencies that administer water rights. The areal geology and ground-water conditions in the Bruneau-Grand View area seemingly typify several basins in southwestern Idaho, and this study is a step toward definition and analysis of regional problems in ground-water geology and the occurrence and availability of ground water for irrigation or other large-scale uses. Owyhee County is subdivided physiographically into a plateau area, the Owyhee uplift, and the Snake River valley. The Bruneau-Grand View area is largely within the Snake River valley. The climate is arid and irrigation is essential for stable agricultural development. Nearly all usable indigenous surface water in the area is appropriated, including freshet flow in the Bruneau River, which is used for power generation at the C. J. Strike Dam. However, with storage facilities additional land could be irrigated, and some land may be irrigated with Snake River water if suitable reclamation projects are constructed. Sedimentary and igneous rocks exposed in the area range in age from Miocene to Recent. The igneous rocks include silicic and basic intrusive and extrusive bodies, and the sedimentary rocks are compacted stream and lake sediments. The rocks contain economically important artesian aquifers; the principal ones are volcanic rocks in which ground water is imperfectly confined beneath sediments of the Idaho formation, thus forming a leaky artesian system. The altitude of the piezometric surface of the artesian water does not exceed about 2,700 feet above mean sea level. In some areas, where the land surface is below that altitude, the artesian system discharges water through springs and seeps and locally causes waterlogging and development of alkali soil. In chemical quality much of the water is unsuitable for irrigation and domestic use. The water contains a relatively moderate amount of dissolved solids, but the percent sodium and the concentration of fluoride are excessive for some uses. The quality of the water for irrigation ranges from excellent in the southern part of the artesian system to unsuitable in the northern part. All the artesian ground water that was sampled contained excessive amounts of fluoride. There is a substantial supply of undeveloped artesian water in the area, but sustained use of the water for irrigation may not be feasible unless provisions can be made for adequate soil drainage and soil amendment, because of the high percentage of sodium in the water. Detailed hydrologic and geologic study of the area should precede development.

Idaho↗

Strength in Numbers: Describing the Flooded Area of Isolated Wetlands

Thousands of isolated, freshwater wetlands are scattered across the karst1 landscape of central Florida. Most are small (less than 15 acres), shallow, marsh and cypress wetlands that flood and dry seasonally. Wetland health is threatened when wetland flooding patterns are altered either by human activities, such as land-use change and ground-water pumping, or by changes in climate. Yet the small sizes and vast numbers of isolated wetlands in Florida challenge our efforts to characterize them collectively as a statewide water resource. In the northern Tampa Bay area of west-central Florida alone, water levels are measured monthly in more than 400 wetlands by the Southwest Florida Water Management Distirct (SWFWMD). Many wetlands have over a decade of measurements. The usefulness of long-term monitoring of wetland water levels would greatly increase if it described not just the depth of water at a point in the wetland, but also the amount of the total wetland area that was flooded. Water levels can be used to estimate the flooded area of a wetland if the elevation contours of the wetland bottom are determined by bathymetric mapping. Despite the recognized importance of the flooded area to wetland vegetation, bathymetric maps are not available to describe the flooded areas of even a representative number of Florida's isolated wetlands. Information on the bathymetry of isolated wetlands is rare because it is labor intensive to collect the land-surface elevation data needed to create the maps. Five marshes and five cypress wetlands were studied by the U.S. Geological Survey (USGS) during 2000 to 2004 as part of a large interdisciplinary study of isolated wetlands in central Florida. The wetlands are located either in municipal well fields or on publicly owned lands (fig. 1). The 10 wetlands share similar geology and climate, but differ in their ground-water settings. All have historical water-level data and multiple vegetation surveys. A comprehensive report by Haag and others (2005) documents bathymetric mapping approaches, the frequency of flooding in different areas of the wetlands, and the relation between flooding and vegetation in these wetlands. This fact sheet describes bathymetric mapping approaches and partial results from two natural marshes (Hillsborough River State Park Marsh, and Green Swamp Marsh) and one impaired marsh (W-29 Marsh) that is located on a municipal well field and is affected by ground-water withdrawals. (fig. 1).

Fact Sheet↗

Geology and ground water for land-use planning in the Eagle River-Chugiak area, Alaska

The Eagle River — Chugiak area is a rapidly growing residential part of the Greater Anchorage Area Borough, south-central Alaska. High-density, urban development in some parts of the area may be restricted because of the nature of the surficial geologic materials and their hydrologic characteristics. This report assembles all information collected by the U.S. Geological Survey on the geology and ground-water resources of the Eagle River — Chugiak area. The study area lies mostly within the Cook Inlet — Susitna Lowland and consists of low hills and intervening channels, hummocky ridges, sloping alluvial fans, and low-lying tidal flats that border Knik Arm. The eastern part of the area lies on the steep slopes of the Chugach Mountains. Drainage is generally to the west and northwest, except that locally the slopes drain southwesterly to the Eagle River, the major stream of the area.

Alaska↗

Water resources of the Indianapolis area, Indiana

Water used in the Indianapolis area comes from two sources: the White River and tributary streams and the underground reservoirs formed by the underlying glacial drift and limestone. Surface-water sources provide about 60 mgd (million gallons per day) for public supply and an additional 300 mgd is used by private industries and is returned directly to the streams. About 60 mgd is taken from ground-water sources by public water supplies and industries. The total use of water, therefore, is about 420 mgd. The city of Indianapolis and several adjacent urban communities are supplied through the surface-water sources by a private water company, the Indianapolis Water Co. Water is impounded in the Geist Reservoir on Fall Creek. At Broad Ripple, on White River, a low dam is used to divert river water into a feeder canal to a treatment plant. Expansion of the present facilities of this company is in progress. A new reservoir with a capacity about equal to that of Geist Reservoir is being constructed on Cicero Creek, a tributary of the White River. These combined river sources will provide an abundant supply of good water in excess of present demands. This will permit expansion of surface-water use for public, commercial, and industrial supply in the service area of this water company. Industry is the heaviest user of ground water in the area. Of the 56 mgd of ground water pumped in 1952 about 70 percent was used by industry. Agriculture was next with a pumpage of about 15 percent and the remainder or 15&middot; percent was for public and private water supply. The ground water is of relatively uniform composition and temperature. Difficulties in supplying water have occurred and will continue to occur from time to time when demands on ground-water sources are excessively heavy for long periods of time and locally where pumped wells are too closely spaced. Under such conditions ground-water levels decline rapidly and remain depressed for some time. Such a condition may constitute what could be called a water shortage. As the demand for water increases there is need for conservation and wise use of available surface and ground-water supplies.

Indiana↗

Ground-water withdrawals in Clinton, Eaton, and Ingham counties, Michigan

The Tri-County region includes Clinton, Eaton, and Ingham Counties in the south-central Lower Peninsula of Michigan (fig. 1). People in the Lansing Metropolitan area, which is located near the center of this region, generally enjoy high-quality drinking water. In fact, taste testers ranked Lansing's water as second in the Nation at the 1988 American Water Resources Association Water-Use Symposium in Tucson, Arizona. However, a drought in 1988 and subsequent water rationing within the Tri-County region prompted local communities to assess the adequacy of water resources for future needs. As part of that effort, this fact sheet provides a brief overview of the development of ground-water resources within the region.

Michigan↗

Water resources of the Blue Earth River watershed, south-central Minnesota

The Blue Earth River Watershed in Minnesota includes 3,106 square miles of land surface, which varies from fairly flat to gently rolling. The drainage extends south to include an additional 450 square miles in Iowa. The western, southern, and eastern boundaries are end moraines formed by Pleistocene glaciers. Major streams have eroded channels 40 to 75 feet deep in headwater regions and 150 to 200 feet deep near the mouth of the Blue Earth River at Mankato. In their lower reaches major streams have cut through glacial deposits and into underlying bedrock (described on ground-water sheet).

Minnesota↗

Base-Flow Index Grid for the Conterminous United States

This 1-kilometer raster (grid) dataset for the conterminous United States was created by interpolating base-flow index (BFI) values estimated at U.S. Geological Survey (USGS) streamgages. Base flow is the component of streamflow that can be attributed to ground-water discharge into streams.

Open-File Report↗

Test-observation well near Davenport, Washington: description and preliminary results

The 750-foot test-observation well drilled near Davenport, Wash., is one of several drilled to date (1972) to provide information on ground-water conditions in selected areas of the State. The well provides information on aquifer characteristics in this area which are not available from existing deep irrigation wells. The well was drilled by air-rotary methods and penetrates eight aquifer zones (A through H); the upper 75 feet of the well is cased, and the remainder of the hole is open in basalt. Test pumping during drilling showed that the well had specific capacities of (1) 4-8 gpm (gallons per minute) per foot of drawdown when at the 255-foot depth and open to aquifers A through D, (2) 5.6 gpm per foot of drawdown when at the 640-foot depth and open to aquifers A through G, and (3) 76 5 gpm per foot of drawdown when at the full 750-foot depth and open to all eight aquifers. The tests indicate that most of the water available to the well is from the deepest aquifer (zone H). Borehole geophysical logging supplemented the drillers log of the well and provided information on natural gamma radiation, water temperature and resistivity, and borehole diameter. In the completed well each aquifer zone is isolated by cement seals, and piezometer pipes installed to zones B through H allow a basis for defining the vertical hydraulic gradient and ground-water movement in the area. The pipes also permit chemical quality monitoring of water in the various aquifer zones. An additional pipe, installed for providing thermistor access, allows recording of the geothermal gradient in the well which provides a basis for estimating vertical ground-water movement in the area.

Washington↗

Acid rain and its effects on streamwater quality on Catoctin Mountain, Maryland

The U.S. Geological Survey (USGS) is the Nation's largest water-science and water-information agency. The mission of the Water Resources Division of the USGS is to provide the hydrologic information and understanding needed for the best management of the Nation's water resources. To fulfill this mission, the USGS conducts water-quality and other types of investigations of the Nation's surface- and ground-water resources.

Maryland↗