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At least 685 records · Page 38Linked to original sources
USGS1994

Overview of environmental and hydrogeologic conditions at Dillingham, Alaska

The remote city of Dillingham is at the northern end of Bristol Bay in southwestern Alaska. The hydrology of the area is strongly affected by the mild maritime climate and local geologic conditions. Dillingham residents obtain drinking water from both deep and shallow aquifers composed of gravels and sands and separated by layers of clay underlying the community. Alternative sources of drinking water are limited to the development of new wells because surface-water sources are of inadequate quantity or quality or are located at too great a distance from the population. The Federal Aviation Administration owns or operates airway support facilities in Dillingham and wishes to consider the severity of contamination and the current environmental setting when they evaluate options for compliance with environmental regulations at their facilities. This report describes the climate. vegetation, geology, soils, ground-water and surface-water hydrology, and flood potential of the areas surrounding the Federal Aviation Administration facilities near Dillingham.

Open-File Report↗
USGS2008

Current (2004-07) conditions and changes in ground-water levels from predevelopment to 2007, Southern High Plains aquifer, east-central New Mexico: Curry County, Portales, and Causey Lingo underground water basins

The Southern High Plains aquifer is the principal aquifer in Curry and Roosevelt Counties, N. Mex., and primary source of water in southeastern New Mexico. Successful water-supply planning for New Mexico's Southern High Plains requires knowledge of the current aquifer conditions and a context to estimate future trends given current aquifer-management policy. This report provides a summary of the current (2007) water-level status of the Southern High Plains aquifer in New Mexico, including a basis for estimating future trends by comparison with historical conditions. This report includes estimates of the extent of ground-water level declines in the Curry County, Portales, and Causey-Lingo Ground-water Management Area parts of the High Plains Aquifer in eastern New Mexico since predevelopment. Maps representing 2007 water levels, water-level declines, aquifer saturated thickness, and depth to water accompanied by hydrographs from representative wells for the Southern High Plains aquifer in the Curry County, Portales, and Causey Lingo Underground Water Basins were prepared in cooperation with the New Mexico Office of the State Engineer. The results of this mapping show the water level declined as much as 175 feet in the study area at rates as high as 1.76 feet per year.

New Mexico↗
USGS2007

Nitrogen species in soil, sediment, and ground water at a former sewage-treatment wastewater lagoon: Naval Air Station Whidbey Island, Island County, Washington

The potential for contamination of ground water from remnant sewage sludge in re-graded sediments of a deconstructed sewage-treatment lagoon was evaluated. Ground-water levels were measured in temporary drive-point wells, and ground-water samples were collected and analyzed for nutrients and other water-quality characteristics. Composite soil and sediment samples were collected and analyzed for organic carbon and nitrogen species. Multiple lines of evidence, including lack of appreciable organic matter in sediments of the former lagoon, agronomic analysis of nitrogen, the sequestration of nitrogen in the developing soils at the former lagoon, and likely occurrence of peat deposits within the aquifer material, suggest that the potential for substantial additions of nitrogen to ground water beneath the former sewage lagoon resulting from remnant sewage sludge not removed from the former lagoon are small. Concentrations of nitrogen species measured in ground-water samples were small and did not exceed the established U.S. Environmental Protection Agency’s maximum contaminant levels for nitrate (10 milligrams per liter). Concentrations of nitrate in ground-water samples were less than the laboratory reporting limit of 0.06 milligram per liter. Seventy to 90 percent of the total nitrogen present in ground water was in the ammonia form with a maximum concentration of 7.67 milligrams per liter. Concentrations of total nitrogen in ground water beneath the site, which is the sum of all forms of nitrogen including nitrate, nitrite, ammonia, and organic nitrogen, ranged from 1.15 to 8.44 milligrams per liter. Thus, even if all forms of nitrogen measured in ground water were converted to nitrate, the combined mass would be less than the maximum contaminant level. Oxidation-reduction conditions in ground water beneath the former sewage lagoon were reducing. Given the abundant supply of ambient organic carbon in the subsurface and in ground water at the former lagoon, any nitrate that may leach from residual sludge and be transported to ground water with recharge is expected to be quickly denitrified or transformed to nitrite and ammonia under the strongly reducing geochemical conditions that are present. Concentrations of organic carbon, the primary constituent of sewage sludge, in sediments of the former sewage lagoon were less than 1 percent, indicating a near absence of organic matter. The amount of total nitrogen present in the sediments at the former sewage lagoon was only about 25 percent of the amount typically present in developed agricultural soils. The lack of substantial carbon and nitrogen in sediments of the former sewage lagoon indicates that surficial sediments of the former lagoon are essentially devoid of residual sewage sludge. The largest concentration of total nitrogen measured in soil samples from the former sewage lagoon (330 milligrams per kilogram) was used to calculate an estimate of the amount of nitrogen that might be leached from residual sewage sludge by recharge. During the first two years following deconstruction of the former sewage lagoon, the concentration of total nitrogen in recharge leachate might exceed 10 milligrams per liter but the recharge leachate would not likely result in substantial increases in the nitrate concentration in ground water to concentrations greater than the drinking-water maximum contaminant level of 10 milligrams per liter.

Washington↗
USGS2008

Effects of Land-Use Changes and Ground-Water Withdrawals on Stream Base Flow, Pocono Creek Watershed, Monroe County, Pennsylvania

The Pocono Creek watershed drains 46.5 square miles in eastern Monroe County, Pa. Between 2000 and 2020, the population of Monroe County is expected to increase by 70 percent, which will result in substantial changes in land-use patterns. An evaluation of the effect of reduced recharge from land-use changes and additional ground-water withdrawals on stream base flow was done by the U.S. Geological Survey (USGS) in cooperation with the U.S. Environmental Protection Agency (USEPA) and the Delaware River Basin Commission as part of the USEPA?s Framework for Sustainable Watershed Management Initiative. Two models were used. A Soil and Water Assessment Tool (SWAT) model developed by the USEPA provided areal recharge values for 2000 land use and projected full buildout land use. The USGS MODFLOW-2000 ground-water-flow model was used to estimate the effect of reduced recharge from changes in land use and additional ground-water withdrawals on stream base flow. This report describes the ground-water-flow-model simulations. The Pocono Creek watershed is underlain by sedimentary rock of Devonian age, which is overlain by a veneer of glacial deposits. All water-supply wells are cased into and derive water from the bedrock. In the ground-water-flow model, the surficial geologic units were grouped into six categories: (1) moraine deposits, (2) stratified drift, (3) lake deposits, (4) outwash, (5) swamp deposits, and (6) undifferentiated deposits. The unconsolidated surficial deposits are not used as a source of water. The ground-water and surface-water systems are well connected in the Pocono Creek watershed. Base flow measured on October 13, 2004, at 27 sites for model calibration showed that streams gained water between all sites measured except in the lower reach of Pocono Creek. The ground-water-flow model included the entire Pocono Creek watershed. Horizontally, the modeled area was divided into a 53 by 155 cell grid with 6,060 active cells. Vertically, the modeled area was discretized into four layers. Layers 1 and 2 represented the unconsolidated surficial deposits where they are present and bedrock where the surficial deposits are absent. Layer 3 represented shallow bedrock and was 200 ft (feet) thick. Layer 4 represented deep bedrock and was 300 ft thick. A total of 873 cells representing streams were assigned to layer 1. Recharge rates for model calibration were provided by the USEPA SWAT model for 2000 land-use conditions. Recharge rates for 2000 for the 29 subwatersheds in the SWAT model ranged from 6.11 to 22.66 inches per year. Because the ground-water-flow model was calibrated to base-flow data collected on October 13, 2004, the 2000 recharge rates were multiplied by 1.18 so the volume of recharge was equal to the volume of streamflow measured at the mouth of Pocono Creek. During model calibration, adjustments were made to aquifer hydraulic conductivity and streambed conductance. Simulated base flows and hydraulic heads were compared to measured base flows and hydraulic heads using the root mean squared error (RMSE) between measured and simulated values. The RMSE of the calibrated model for base flow was 4.7 cubic feet per second for 27 locations, and the RMSE for hydraulic heads for 15 locations was 35 ft. The USEPA SWAT model was used to provide areal recharge values for 2000 and full buildout land-use conditions. The change in recharge ranged from an increase of 37.8 percent to a decrease of 60.8 percent. The ground-water-flow model was used to simulate base flow for 2000 and full buildout land-use conditions using steady-state simulations. The decrease in simulated base flow ranged from 3.8 to 63 percent at the streamflow-measurement sites. Simulated base flow at streamflow-gaging station Pocono Creek above Wigwam Run near Stroudsburg, Pa. (01441495), decreased 25 percent. This is in general agreement with the SWAT model, which estimated a 30.6-percent loss in base flow at the streamflow-gaging station.

Scientific Investigations Report↗
USGS2003

Ground-Water Resources in the Black Hills Area, South Dakota

The availability of ground-water resources in the Black Hills area is influenced by many factors including location, local recharge and ground-water flow conditions, and structural features. Thus, the availability of ground water can be extremely variable throughout the Black Hills area, and even when water is available, it may not be suitable for various uses depending on the water quality. The major bedrock aquifers in the Black Hills area are the Deadwood, Madison, Minnelusa, Minnekahta, and Inyan Kara aquifers. Minor bedrock aquifers occur in other hydrogeologic units, including confining units, due to fracturing and interbedded permeable layers. Various information and maps are presented in this report that describe availability and quality of ground-water resources in the Black Hills area. However, there is no guarantee of obtaining usable water at any location due to the extreme potential variability in conditions that can affect the availability and quality of ground water in the area. Maps presented in this report include the distribution of hydrogeologic units; depth to the top of the five formations that contain major aquifers; thickness of the five formations that contain major aquifers; potentiometric maps for the five major aquifers; saturated thickness of the Madison and Minnelusa aquifers; water temperature in the Madison aquifer; specific conductance in the Madison, Minnelusa, and Inyan Kara aquifers; hardness in the Inyan Kara aquifer; sulfate concentrations in the Minnelusa aquifer; and radon concentrations in the Deadwood aquifer. Water quality of the major aquifers generally is very good in and near outcrop areas but deteriorates progressively with distance from the outcrops. In the Minnelusa aquifer, an abrupt increase in concentrations of dissolved sulfate occurs downgradient from outcrop areas, where a zone of active anhydrite dissolution occurs. Most limitations for the use of ground water are related to aesthetic qualities associated with hardness and high concentrations of chloride, sulfate, sodium, manganese, and iron. Very few health-related limitations exist for ground water; most limitations are for radionuclides, such as radon and uranium. In addition, high concentrations of arsenic have been measured in a few samples from the Minnelusa aquifer.

Water-Resources Investigations Report↗
USGS1957

Ground-water possibilities south of the Snake River between Twin Falls and Pocatello, Idaho

The Snake River Plain and tributary valleys south of the Snake River between Twin Falls and Pocatello, Idaho (here called the South Side area), contain about 180,000 acres of irrigated land, of which 145,000 acres is irrigated with surface water and 35,000 is irrigated wholly or partly with ground water. The area also contains more than 200,000 acres of arable land that is idle or used only for grazing because it lacks irrigation water. Most of the surface-water supply is already used or reserved, and some land now irrigated needs supplemental water. The climate of the area ranges from semiarid on the Snake River Plain to subhumid on higher mountains. The average annual precipitation at lowland stations ranges from about 9 to 12 inches. The principal sources of ground water are extrusive volcanic rocks of silicic to intermediate composition, basalt, and sand and gravel. Ground water occurs commonly under artesian conditions in the silicic to intermediate volcanic rocks and in sand and gravel tongues and lenses in lake beds. Basalt and alluvium commonly contain unconfined water. The area of this report is divided into 13 roughly defined ground-water districts, some of which are further divided into subdistricts. The known geologic and hydrologic factors of each area are summarized and a preliminary appraisal is made of the ground-water resources in relation to land resources and to the regimen of streams. The current state of development, proposed new developments, and ground-water potential of each division are discussed. The Dry Creek district is the most intensively irrigated area in Idaho in which wells furnish the water supply. Ground water occurs under both artesian and water-table conditions. More than 53,000 acre-feet of ground water was pumped in 1954. There are large areas of undeveloped arable land in the district, but pumping in some parts of the district currently is approaching or surpasses the perennial yield of the ground-water reservoirs. The Golden Valley district contains considerable arable land but, owing to the relatively great depth to water and the generally poor yield of wells, the prospects for extensive ground-water development are not promising. In the Oakley district ground water is pumped from alluvium to supplement surface water and to bring new land into production. The ground water will be fully exploited within a few years if the present rate of development by individual landowners continues. The total area of nonirrigated land far exceeds the amount that could be irrigated with indigenous ground water. Both artesian and unconfined water occur in the Burley district. Most existing wells tap unconfined water in the southern part where there are still large tracts of idle arable land. Pumping lifts are rather high. The South Walcott district contains a considerable acreage of arable land and is underlain by excellent aquifers. The effect that heavy pumping would have on the flow of the Raft and Snake Rivers and on seepage from Lake Walcott is Taot well understood. Presumably substantial pumping would be feasible without direct deleterious effects. The Raft River basin, including the Elba and Almo-Yost subbasins, is the largest district in the South Side area. Ground water occurs in both unconfined and artesian aquifers. Possibly as much as 150,000 acres of dry land is irrigable, but the ground-water supply presumably is sufficient to irrigate only a few thousand acres in addition to the approximately 40,000 now irrigated with surface and ground water. Pumping of wells at some locations would deplete the base flow of the Raft River and would be competitive with surface-water use. The United States Bureau of Reclamation has started construction of the Michaud Flats Irrigation Project in the Western Michaud Flats district. The adopted reclamation plan is to irrigate about 10,000 acres, using surface water pumped from American Falls Reservoir and ground water pumped from wells. Ground water in part of the district is tributary to the reservoir. Withdrawals of ground water will be compensated in part by the return of waste water to the reservoir and to the Snake River. The Eastern Michaud Flats district contains more arable land and has better aquifers than the Western Michaud Flats district, but pumping might reduce noticeably the discharge of ground water to the American Falls Reservoir. The Bureau of Indian Affairs plans to develop about 13,600 acres of Indian land with water stored in Palisades and American Falls Reservoirs. Virtually nothing is known about ground-water conditions in the Arbon and Rockland Valleys and in several small areas such as the Basin district, the Albion basin, and along the northern border of the Sublett Range. Preliminary studies have been made in three areas, the Dry Creek, Raft River, and Western. Michaud Flats districts. None has been studied comprehensively. The available data for each district are summarized in tabular form. Further investigations in the area are needed and should include accurate hydrologic mapping. Studies are needed of the sources and amounts of groundwater recharge, of the effects of ground-water withdrawals on the total water supply, and of numerous related problems.

Idaho↗
USGS1997

Base-flow characteristics of streams in the Valley and Ridge, the Blue Ridge, and the Piedmont physiographic provinces of Virginia

Growth within the Valley and Ridge, the Blue Ridge, and the Piedmont Physiographic Provinces of Virginia has focused concern about allocation of surface-water flow and increased demands on the ground-water resources. The pur pose of this report is to (.1) describe the base-flow characteristics of streams, (2) identify the regional differences in these flow characteristics, and (3) describe, if possible, the potential surface-water and ground-water yields of basins on the basis of the base-flow characteristics. Base-flow characteristics are presented for streams in the Valley and Ridge, the Blue Ridge, and the Piedmont Physiographic Provinces of Virginia. The provinces are separated into five regions: (1) Valley and Ridge, (2) Blue Ridge, (3) Piedmont/Blue Ridge transition, (4) Piedmont northern, and (5) Piedmont southern. Different flow statistics, which represent stream flows predominantly comprised of base flow, were determined for 217 continuous-record stream flow-gaging stations from historical mean daily discharge and for 192 partial-record streamflow gaging stations by means of correlation of discharge measurements. Variability of base flow is represented by a duration ratio developed during this investigation. Effective recharge rates were also calculated. Median values for the different flow statis tics range from 0.05 cubic foot per second per square mile for the 90-percent discharge on the streamflow-duration curve to 0.61 cubic foot per second per square mile for mean base flow. An excellent estimator of mean base flow for the Piedmont/Blue Ridge transition region and Piedmont southern region is the 50-percent discharge on the streamflow-duration curve, but it tends to underestimate mean base flow for the remaining regions. The base-flow variability index ranges from 0.07 to 2.27, with a median value of 0.55. Effective recharge rates range from 0.07 to 33 .07 inches per year, with a median value of 8.32 inches per year. Differences in the base-flow characteristics exist between regions. The median discharges for the Valley and Ridge, the Blue Ridge, and the Piedmont/Blue Ridge transition regions are higher than those for the Piedmont regions. Results from statistical analysis indicate that the regions can be ranked in terms of base-flow characteristics from highest to lowest as follows: (1) Piedmont/Blue Ridge transition, (2) Valley and Ridge and Blue Ridge, (3) Piedmont south ern, and (4) Piedmont northern. The flow statis tics are consistently higher and the values for base-flow variability are lower for basins within the Piedmont/Blue Ridge transition region relative to those from the other regions, whereas the basins within the Piedmont northern region show the opposite pattern. The group rankings of the base-flow characteristics were used to designate the potential surface-water yield for the regions. In addition, an approach developed for this investigation assigns a rank for potential surface-water yield to a basin according to the quartiles in which the values for the base-flow characteristics are located. Both procedures indicate that the Valley and Ridge, the Blue Ridge, and the Piedmont/ Blue Ridge transition regions have moderate-to high potential surface-water yield and the Piedmont regions have low-to-moderate potential surface-water yield. In order to indicate potential ground-water yield from base-flow characteristics, aquifer properties for 51 streamflow-gaging stations with continuous record of streamflow data were determined by methods that use streamflow records and basin characteristics. Areal diffusivity ranges from 17,100 to 88,400 feet squared per day, with a median value of38,400 feet squared per day. Areal transmissivity ranges from 63 to 830 feet squared per day, with a median value of270 feet squared per day. Storage coefficients, which were estimated by dividing areal transmissivity by areal diffusivity, range from approximately 0.001 to 0.019 (dimensionless), with a median value of 0.007. The median value for areal diffusivity decreases as potential surface-water yield of the basins increases. The ranking of a real diffusivity does not correspond with the ranking of potential surface-water yield for either the regions or the basins. Areal transmissivity generally increases as storage coefficient increases; however, basins with low potential surface-water yield generally have high values of areal transmissivity associated with low values of storage coefficient over a narrow range relative to those from basins designated as having moderate-to-high potential surface-water yield. Although the basins with high potential surface-water yield tend to have comparatively lower values for areal transmissivity, storage coefficients generally are large when compared to those from basins with similar values of a real transmissivity but different potential surface-water yield. Aquifer properties were grouped by potential surface-water yield and were related to hydro geologic units categorized by large, medium, and small well yields for the Valley and Ridge Physio graphic Province and for the Blue Ridge and the Piedmont Physiographic Provinces. Generally, no trend is evident between areal diffusivity and the hydrogeologic units. Some of the high values of a real diffusivity are associated with basins predominantly underlain by hydrogeologic units with small well yields, especially basins with a low potential surface-water yield. Areal transmissivity and storage coefficient tend to decrease, which is the expected trend, as more ofthe basin is underlain by the hydrogeologic unit with small well yields in the Valley and Ridge Physiographic Province. A similar trend is indicated for the hydrogeologic unit with medium well yields in the Blue Ridge and the Piedmont Physiographic Provinces. Areal transmissivity and storage coefficient tend to increase, which is not the expected trend, as more of the basin is underlain by the hydrogeologic unit with small well yields in the Blue Ridge and the Piedmont Physiographic Provinces. The base-flow characteristics of a basin may provide a relative indication of the potential ground-water yield; but other factors need to be considered, such as geologic structure, lithology, precipitation, relief, and degree of hydraulic interrconnection between the regolith and bedrock.

Virginia↗
USGS1999

Ground-water resources of Kings and Queens counties, Long Island, New York

From 1981 through 1986, the U.S. Geological Survey investigated the ground-water system of western Long Island, New York, including Kings and Queens counties. This report describes the structure and operation of the western part of the Long Island ground-water system, and the hydrologic effects associated with human development from 1900 to the early 1980's. Recent (early 1980's) ground-water quantity and quality characteristics are described.

New York↗
USGS1997

Design and implementation of the National Water-Quality Assessment Program: a United States example: understanding the limitations of using compliance-monitoring data to assess the water quality of a large river basin

In the 1980s it was determined that existing ambient and compliance-monitoring data could not satisfactorily evaluate the results of hundreds of billions of dollars spent for water-pollution abatement in the United States. At the request of the US Congress, a new programme, the National Water-Quality Assessment, was designed and implemented by government agency, the US Geological Survey (USGS). The Assessment has reported status and trends in surface- and ground-water quality at national, regional, and local scales since 1991. The legislative basis for US monitoring and data-sharing policies are identified as well as the successive phases of the design and implementation of the USGS Assessment. Application to the Danube Basin is suggested. Much of the water-quality monitoring conducted in the United States is designed to comply with Federal and State laws mandated primarily by the Clean Water Act of 1987 and the Safe Drinking Water Act of 1986. Monitoring programs generally focus on rivers upstream and downstream of point-source discharges and at water-supply intakes. Few data are available for aquifer systems, and chemical analyses are often limited to those constituents required by law. In most cases, the majority of the available chemical and streamflow data have provided the information necessary to meet the objectives of the compliance-monitoring programs, but do not necessarily provide the information requires for basin-wide assessments of the water quality at the local, regional, or national scale.

Book chapter↗
USGS1968

Ground-water reconnaissance of the Santa Barbara-Montecito area, Santa Barbara County, California

This is the third interpretive report prepared by the U.S. Geological Survey in cooperation with the Santa Barbara County Water Agency on the groundwater resources of areas along the south coast of the county. The two previous reports--one by J. E. Upson in 1951 and another by R. E. Evenson, H. D. Wilson, Jr., and K. S. Muir--were on ground-water conditions in the Goleta and Carpinteria basins. The Santa Barbara-Montecito area is between those two basins-the Goleta basin on the west and the Carpinteria basin on the east. This area of about 30 square miles extends from the Pacific Ocean on the south to the Santa Inez Mountains on the north. The city of Santa Barbara and the towns of Montecito and Summerland are within the area. The Santa Barbara-Montecito area is a low-lying flat section of the coastal plain. Farther inland are highlands of consolidated rock and terrace deposits. The highlands are areas of uplift, folding, and faulting, and the lowlands are structural depressions. Most of the urban development in the area has been in the lowlands. The unconsolidated deposits that have partly filled the structural depressions make up the ground-water reservoir of the Santa Barbara-Montecito area. They include the Santa Barbara Formation of Pliocene and Pleistocene age, the Casitas Formation of Pleistocene age, and the alluvium of late Pleistocene and Recent age. These deposits underlie an area of about 20 square miles and have a maximum thickness of about 2,000 feet. The consolidated rocks of Tertiary age that underlie and form the boundaries of the ground-water reservoir contain ground water in fractures and in sandstone beds. However, the consolidated rocks are not an important source of ground water. In 1959, a year the ground-water basins were full and ground water in storage was at a maximum, storage in the Santa Barbara area was 184,000 acre-feet, and storage in the Montecito area was 97,000 acre-feet. By 1964, in response to below-average recharge and continued withdrawal by pumping, the quantity of ground water in storage in the Santa Barbara area had decreased to 178,000 acre-feet. Because of a reduction in pumpage, there was little change in storage in the Montecito area between 1959 and 1964. Deep percolation of rain, seepage from streams, and subsurface inflow from consolidated rocks are the main sources of recharge to the ground-water reservoir in the Santa Barbara-Montecito area. The most important discharge is by pumping.The long-term perennial yield of the ground-water reservoir of the Santa Barbara area is estimated to be 1,700-2,000 acre-feet. Present data are insufficient to accurately determine the perennial yield of the reservoir in the Montecito area, but it is estimated to be about 2,500 acre-feet. Most ground water in the Santa Barbara-Montecito area is suitable for general use. However, ground water in some of the consolidated rocks and in the shallow unconsolidated deposits adjacent to the coast is too saline for most uses. Seawater intrusion has occurred in the Santa Barbara area and the western part of the Montecito area. The intrusion, however, is limited to the upper part of the nearshore shallow alluvial deposits and contaminates only wells which were constructed without a near-surface seal.

California↗
USGS1949

Ground-water supplies of the Ypsilanti area, Michigan

As of the date of this report (August 1945), the major water users in the Ypsilanti area are: (1) the city of Ypsilanti, (2) the Willow Run bomber plant, built by the Federal Government and operated by the Ford Motor Co., and (3) the war housing project of the Federal Public Housing Authority, designated in this report the Willow Run Townsite. The city, bomber plant, and townsite have required large quantities of water for domestic and industrial uses, and the necessary water supplies have been developed from wells. The Federal Works Agency had the responsibility of deciding whether the existing water facilities were adequate to meet the expected demands and determining the character of any additional public water-supply facilities that might be constructed with Federal assistance. In order to appraise the ground-water resources of the area the Federal Works Agency requested the Geological Survey to investigate the adequacy of the existing supplies and the availability of additional water. The present report is the result of the investigation, which was made in cooperation with the Michigan Geological Survey Division. The water supplies of the three major users are obtained from wells penetrating glacial and associated sands and gravels. Supplies for the city of Ypsilanti and the Willow Run bomber plant are obtained from wells in the valley of the Huron River; the supply for the Willow Run Townsite is obtained from wells penetrating glacial gravels underlying the upland northeast of the valley. The bedrock formations of the area either yield little water to wells or yield water that is too highly mineralized for most uses. The water supply for the bomber plant is obtained from three closely spaced, highly productive wells at the northern edge of the Huron River, a little more than 3 miles southeast of Ypsilanti. The water receives complete treatment in a modern treatment plant. River water also can be treated and has been used occasionally in the winter and spring. The average daily pumpage during periods of maximum production at the bomber plant has been 4.5 to 4.75 million gallons. On June 30, 1945, production of bombers was suspended, and the plant went on a. maintenance basis. The water supply of the bomber-plant well field is replenished by recharge from precipitation and from the Huron River. The evidence shows that recharge from the river is one of the principal sources of water and gives assurance both of the adequacy of the present supply and of the availability of additional water if needed. The safe yield of the three existing wells is estimated to be not less than 6 million gallons per day. The Ypsilanti public water supply is obtained from three tubular wells drilled in 1943, which replaced a number of suction-pumped tubular wells and one large dug well. All the wells penetrate sand and gravel in the bend of the Huron River in the southeastern part of Ypsilanti. The water is treated in a modern treatment plant completed in 1939. The average daily pumpage in million gallons was about 1.68 in 1942, 1.70 in 1943, and 1.66 in 1944. Considerable water was furnished to the Willow Run bomber plant from the Ypsilanti public-supply system during the period from August 1941 through March 1943. The available information indicates that the water pumped from the Ypsilanti well field is replenished by ground-water flow from adjacent stretches of the Huron Valley and from the upland areas outside the valley, from precipitation on the valley in the vicinity of the well field, and possibly from the Huron River. It is believed that sufficient water can be obtained from the well field to meet the expected demand for a considerable time. The safe yield of the present wells is estimated to be not less than 3 million gallons per day, and detailed pumping tests might show that still larger supplies could be safely developed. The water supply of the Willow Run Townsite is obtained from four wells in two well fields about 2 miles apart, one well in the northwest or Prospect and Geddes Road field, and three wells in the southeast or Wiard Road field. The pumpage was originally expected to be 2 to 3 million gallons per day, but it averaged only about 450,000 gallons per day from March 1943 through June 1945. The evidence afforded by logs of wells and by pumping tests indicates that the water-bearing gravels at the townsite are covered by relatively impermeable materials and thus that the rate of recharge is low. However, only relatively small declines in water level have occurred during more than 2 years' operation of the wells, indicating that recharge may occur nearby. The safe yield of the present wells is estimated to be 1.0 to 1.5 million gallons per day, and detailed pumping tests might show it to be somewhat greater. The water supply of the Willow Run Townsite has the smallest potential capacity of the three major ground-water supplies in the area; however, the demand has been relatively small, and no difficulty should arise unless this demand increases greatly. The investigation involved the drilling of 13 test wells to locate additional ground-water supplies, on the assumption that the wartime demand for water in the Ypsilanti area might increase beyond the capacity of the present sources. All 13 wells were drilled at sites selected by the Geological Survey. Two wells on the Willow Run Townsite were drilled by the Federal Public Housing Authority and 11 at other sites by the Federal Works Agency. Records of the wells are given in the report and discussed with respect to the availability of water at the different sites; similarly, the results of the controlled pumping tests made on four of the test wells drilled by the Federal Works Agency are analyzed and discussed with respect to the availability of additional water. The combined results of the test drilling and the pumping tests show that emergency supplies of several million gallons per day can be developed at the sites of the test wells. The best site shown by the test drilling is on the south bank of the Huron River opposite the bomber-plant well field, where a Well with a capacity of several thousand gallons per minute could be constructed if necessary. Three wells in the outwash-filled valley now occupied by Fleming Creek, on two of which pumping tests were made, show that emergency supplies ranging from a few hundred thousand to a million gallons per day could be developed at these test-well sites if necessary. Smaller Supplies ranging from a gallon or two per minute to perhaps 100,000 or 200,000 gallons per day could be developed at the sites of the remaining test Wells. Pumping tests made on the supply wells of the three major water users by the consulting-engineering firms who designed the systems are analyzed and discussed briefly by the authors. The report includes maps and graphs showing the surficial geology of the area, the location of wells, and fluctuations of water level in selected wells. Alsp included are tables giving data on water levels and pumpage, chemical analyses of representative ground waters, and records of wells.

Michigan↗
USGS2005

Questa baseline and pre-mining ground-water quality invistigation. 13. Mineral microscopy and chemistry of mined and unmined porphyry molybdenum mineralization along the Red River, New Mexico: Implications for ground- and surface-water quality

This report is one in a series presenting results of an interdisciplinary U.S. Geological Survey (USGS) study of ground-water quality in the lower Red River watershed prior to open-pit and underground molybdenite mining at Molycorp's Questa mine. The stretch of the Red River watershed that extends from just upstream of the town of Red River to just above the town of Questa includes several mineralized areas in addition to the one mined by Molycorp. Natural erosion and weathering of pyrite-rich rocks in the mineralized areas has created a series of erosional scars along this stretch of the Red River that contribute acidic waters, as well as mineralized alluvial material and sediments, to the river. The overall goal of the USGS study is to infer the pre-mining ground-water quality at the Molycorp mine site. An integrated geologic, hydrologic, and geochemical model for ground water in the mineralized but unmined Straight Creek drainage is being used as an analogue for the geologic, geochemical, and hydrologic conditions that influenced ground-water quality and quantity at the mine site prior to mining. This report summarizes results of reconnaissance mineralogical and chemical characterization studies of rock samples collected from the various scars and the Molycorp open pit, and of drill cuttings or drill core from bedrock beneath the scars and adjacent debris fans.

New Mexico↗
USGS1984

Ground-water conditions and well yields in fractured rocks, southwestern Nevada County, California

This report describes the availability of ground water in the southwestern part of Nevada County, and suggests general guidelines for selecting sites for future ground-water development in the study area. Ground water in this area occurs chiefly in fractures in hard pre-Tertiary metavolcanic and plutonic rocks generally above a depth of 215 feet. Some ground water is found at the contact between alluvium or decomposed granite and the underlying hard rock; little is found in alluvium or colluvium. Mean yield is less than 18 gallons per minute. (USGS)

Water-Resources Investigations Report↗
USGS2007

Demonstration and validation of a regenerated cellulose dialysis membrane diffusion sampler for monitoring ground-water quality and remediation progress at DoD sites (ER-0313)

This final technical report documents the demonstration and validation of regenerated cellulose dialysis membrane diffusion samplers for use in collecting ground water samples for a range of inorganic and organic water-quality parameters. This project, ER-0313, was funded by the Environmental Security Technology Certification Program (ESTCP). The primary objectives of the project were; (1) to determine the usefulness of dialysis samplers in collecting a range of organic and inorganic water quality constituents from ground water, (2) to determine the optimum equilibration times for these constituents to diffuse into the dialysis sampler, (3) to compare water quality results and sampling costs from samples collected with dialysis samplers to samples collected with a low-flow purging technique and polyethylene diffusion bag (PDB) samplers, and (4) to transfer the technology while gaining regulatory acceptance. Field comparisons were conducted at three Department of Defense (DoD) sites: (1) Naval Air Engineering Station (NAES) Lakehurst, NJ, (2) Naval Base Ventura County (NBVC), Port Hueneme and Pt. Mugu, CA, and (3) Naval Air Warfare Center (NAWC) West Trenton, NJ. Dialysis samplers were found to cost significantly less than samples collected with a low-flow purging procedure. Field sampling time was reduced by a factor of more than six times, compared to low-flow purging. The total sampling costs per sample was estimated to be three times less, compared to low-flow purging.

Technical Report↗