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USGS2003

Water Resources Data, Florida, Water Year 2002, Volume 4. Northwest Florida

The U.S. Geological Survey (USGS), in cooperation with Federal, State, and local agencies, obtains a large amount of data on the water resources of the State of Florida each water year. These data, accumulated during many water years, constitute a valuable database that is used by water-resources managers, emergency-management officials, and many others to develop an improved understanding of water resources within the State. This report series for the 2002 water year for the state of Florida consists of records for continuous or daily discharge for 392 streams, periodic discharge for 15 streams, continuous or daily stage for 191 streams, periodic stage for 13 streams, peak stage and discharge for 33 streams, continuous or daily elevations for 14 lakes, periodic elevations for 49 lakes, continuous ground-water levels for 418 wells, periodic ground-water levels for 1,287 wells, and quality-of-water for 116 surface-water sites and 291 wells. This volume (Volume 4, Northwest Florida)contains records of continuous or daily discharge for 67 streams, periodic discharge for 1 stream, continuous or daily stage for 16 streams, periodic stage for 1 stream, peak stage and discharge for 29 streams, continuous or daily elevations for 1 lake, periodic elevations for 3 lakes, continuous ground-water levels for 2 wells, periodic ground-water levels for 3 wells, and quality-of-water for 5 surface-water sites and 0 wells. These data represent the National Water Data System records collected by the U.S. Geological Survey and cooperating local, State, and Federal agencies in Florida.

Water Data Report↗
USGS2004

Water resources data, Florida, water year 2004, volume 4: northeast Florida

This report series for the 2004 water year for the state of Florida consists of records for continuous or daily discharge for 405 streams, periodic discharge for 12 streams, continuous or daily stage for 159 streams, periodic stage for 19 streams, peak stage and discharge for 30 streams, continuous or daily elevations for 14 lakes, periodic elevations for 23 lakes, continuous ground-water levels for 408 wells, periodic ground-water levels for 1,188 wells, and quality-of-water for 140 surface-water sites and 240 wells. This volume (Volume 4, Northwest Florida) contains records of continuous or daily discharge for 75 streams, periodic discharge for 2 streams, continuous or daily stage for 11 streams, periodic stage for 2 streams, peak stage and discharge for 22 streams, continuous or daily elevations for 1 lake, periodic elevations for 0 lakes, continuous ground-water levels for 3 wells, periodic ground-water levels for 0 wells, and quality-of-water for 3 surface-water sites and 0 wells. These data represent the National Water Data System records collected by the U.S. Geological Survey and cooperating local, State, and Federal agencies in Florida.

Water Data Report↗
USGS2005

Water resources data, Florida, water year 2005. Volume 4: Northwest Florida

This report series for the 2005 water year for the state of Florida consists of records for continuous or daily discharge for 429 streams, periodic discharge for 9 streams, continuous or daily stage for 218 streams, periodic stage for 5 streams, peak stage and discharge for 28 streams, continuous or daily elevations for 15 lakes, periodic elevations for 23 lakes, continuous ground-water levels for 401 wells, periodic ground-water levels for 1,098 wells, and quality-of-water for 211 surface-water sites and 208 wells. This volume (Volume 4, Northwest Florida) contains records of continuous or daily discharge for 76 streams, periodic discharge for 2 streams, continuous or daily stage for 14 streams, periodic stage for 0 streams, peak stage and discharge for 20 streams, continuous or daily elevations for 1 lake, periodic elevations for 0 lakes, continuous ground-water levels for 2 wells, periodic ground-water levels for 0 wells, and quality-of-water for 3 surface-water sites and 0 wells. These data represent the National Water Data System records collected by the U.S. Geological Survey and cooperating local, State, and Federal agencies in Florida.

Water Data Report↗
USGS2000

Water Resources Data for Florida, 1999, Volume 4: Northwest Florida

This report series for the 1999 water year for the State of Florida consists of records for continuous or daily discharge for 354 streams, periodic discharge for 17 streams, continuous or daily stage for 121 streams, periodic stage for 1 stream, peak stage and discharge for 38 streams; continuous or daily elevations for 21 lakes, and periodic elevations for 42 lakes; continuous ground-water levels for 408 wells, and periodic ground-water levels for 1,715 wells; quality-of-water for 131 surface-water sites and 198 wells. This volume (Volume 4, Northwest Florida) contains records of continuous or daily discharge for 54 streams, periodic discharge for 1 stream, continuous or daily stage for 15 streams, periodic stage for 1 stream, peak stage and discharge for 30 streams; continuous or daily elevations for 1 lake, periodic elevations for 1 lake; continuous ground-water levels for 1 well, periodic ground-water levels for 0 wells; and quality-of-water for 2 surface-water sites and 0 wells. These data represent the National Water Data System records collected by the U.S. Geological Survey and cooperating local, State, and Federal agencies in Florida.

Water Data Report↗
USGS2000

Water Resources Data: Hawaii and Other Pacific Areas, Water Year 1999. Volume 1. Hawaii

This report includes records on both surface and ground water in the State. Specifically, it contains: (1) Discharge records for 74 stream-gaging stations, 71 miscellaneous streamflow stations, and 88 crest-stage partial-record streamflow stations; (2) water-quality records for 6 streamflow-gaging stations, and 28 partial-record streamflow stations; (3) water-level records for 84 observation wells; (4) water-quality records for 122 observation wells; and (5) accumulated rainfall records for 40 rainfall stations. This series of annual reports for Hawaii began with the 1961 fiscal year (State of Hawaii) with a report that contained only data relating to the quantities of surface water. For the 1964 fiscal year, a similar report was introduced that contained only data relating to water quality. Beginning with the 1975 water year, the report format was changed to include, in one volume, data on quantities of surface water, quality of surface and ground water, and ground-water levels. Beginning with the 1993 water year, accumulated rainfall data were included in the report.

Water Data Report↗
USGS2000

Water Resources Data Minnesota Water Year 1999

The Water Resources Division of the U.S. Geological Survey (USGS), in cooperation with State agencies, obtains a large amount of data pertaining to the water resources of Minnesota each water year. These data, accumulated during many years, constitute a valuable data base for developing an improved understanding of the water resources of the State. To make these data readily available to interested parties outside the USGS, the data are published annually in this report series entitled 'Water Resources Data - Minnesota.' Water-resources data for the 1999 water year (hereinafter 1999) for Minnesota consist of records of stage, discharge, and water quality of streams; and stage of lakes and reservoirs; and water quality of ground water. This volume contains discharge records for 103 stream-gaging stations; stage for 11 lakes and reservoirs; water quality for 13 stream-gaging stations; peak flow data for 87 high-flow partial-record stations; and 15 ground-water observation wells. These data represent a part of the National Water Data System collected by the USGS and cooperating State and Federal agencies in Minnesota.

Water Data Report↗
USGS2002

Water Resources Data--Nebraska, Water Year 2002

The Water Resources Discipline of the U.S. Geological Survey (USGS), in cooperation with State and local agencies, obtains a large amount of data pertaining to the water resources of Nebraska each water year. These data, accumulated during many water years, constitute a valuable data base for developing an improved understanding of the water resources of the State. To make these data readily available to interested parties outside the USGS, the data are published annually in this report series entitled ?Water Resources Data - Nebraska.' The Nebraska water resources data report for water year 2002 includes records of stage, discharge, and water quality of streams; stage and/or contents of lakes and reservoirs; and water levels and quality of ground water in wells. This report contains records of stream stage for 3 stations; stream discharge for 96 continuous and 5 crest-state gaging stations, and 3 miscellaneous and 55 low-flow sites; stream water quality for 23 gaging stations and 5 miscellaneous sites; water elevation and/or contents for 1 lake and 1 reservoir; ground-water levels for 43 observation wells; and ground-water quality for 115 wells. These data represent that part of the National Water Data System collected in and near Nebraska by the U.S. Geological Survey and cooperating local, state and Federal agencies.

Water Data Report↗
USGS2003

Water resources data for New Hampshire and Vermont, water year 2002

The Water Resources Division of the U.S. Geological Survey, in cooperation with State agencies, obtains a large amount of data pertaining to the water resources of New Hampshire and Vermont each water year. These data, accumulated during many water years, constitute a valuable data base for developing an improved understanding of the water resources of the States. To make these data readily available to interested parties outside the U.S. Geological Survey, the data are published annually in this report series entitled 'Water Resources Data-New Hampshire and Vermont.' This report series includes records of stage, discharge, and water quality of streams; contents of lakes and reservoirs; and water levels of ground-water wells. This volume contains records for water discharge at 84 gaging stations; stage records for 5 lakes; month end contents for 2 lakes and reservoirs; and water levels at 38 observation wells. Also included are data for 43 crest-stage partial record stations. Locations of these sites are shown in figures 1 and 2. Additional water data were collected at various sites not involved in the systematic data-collection program and are published under miscellaneous discharge measurements for gaging stations in New Hampshire and Vermont. The data in this report represent that part of the National Water Data System collected by the U.S. Geological Survey and cooperating State and Federal agencies in New Hampshire and Vermont.

Water Data Report↗
USGS2006

Water resources data, Puerto Rico and the U.S. Virgin Islands, water year 2004

The Caribbean Water Science Center of the U.S. Geological Survey (USGS), in cooperation with local and Federal agencies obtains a large amount of data pertaining to the water resources of the Commonwealth of Puerto Rico and the Territory of the U.S. Virgin Islands each water year. These data, accumulated during many water years, constitute a valuable data base for developing an improved understanding of the water resources of the area. To make these data readily available to interested parties outside the U.S. Geological Survey, the data are published annually in this report series entitled 'Water Resources Data for Puerto Rico and the U.S. Virgin Islands.' This report includes records on both surface and ground water. Specifically, it contains: (1) discharge records for 89 streamflow-gaging stations, daily sediment records for 13 sediment stations, stage records for 18 reservoirs, and (2) water-quality records for 20 streamflow-gaging stations, and for 38 ungaged stream sites, 13 lake sites, 2 lagoons, and 1 bay, and (3) water-level records for 72 observation wells. Water-resources data for Puerto Rico for calendar years 1958-67 were released in a series of reports entitled 'Water Records of Puerto Rico.' Water-resources data for the U.S. Virgin Islands for the calendar years 1962-69 were released in a report entitled 'Water Records of U.S. Virgin Islands.' Included were records of streamflow, ground-water levels, and water-quality data for both surface and ground water. Beginning with the 1968 calendar year, surface-water records for Puerto Rico were released separately on an annual basis. Ground-water level records and water-quality data for surface and ground water were released in companion reports covering periods of several years. Data for the 1973-74 reports were published under separate covers. Water-resources data reports for 1975 to 2003 water years consist of one volume each and contain data for streamflow, water quality, and ground water.

Water Data Report↗
USGS2000

Predevelopment water-level map of the Santa Fe Group aquifer system in the middle Rio Grande basin between Cochiti Lake and San Acacia, New Mexico

Because of its increasing population and limited water resources, the Middle Rio Grande Basin between Cochiti Lake and San Acacia, New Mexico, has recently become the subject of intense study. In particular, the U.S. Geological Survey (USGS) in cooperation with the City of Albuquerque has constructed a series of ground-water-flow models of the Tertiary and Quaternary basin-fill deposits of the Santa Fe Group aquifer system (Kernodle and Scott, 1986; Kernodle and others, 1987; Kernodle and others, 1995; Kernodle, 1998; Tiedeman and others, 1998). The ground-water-flow system also has been the focus of hydrochemical studies and other efforts intended largely to help develop an improved flow model. Among the information critical to a thorough understanding of the ground-water-flow system are water-level data that indicate the directions of ground-water flow and the magnitudes of hydraulic gradients in the aquifer prior to perturbation by substantial ground-water withdrawals (under predevelopment conditions).

Water-Resources Investigations Report↗
USGS2001

Occurrence of selected radionuclides in ground water used for drinking water in the United States: A reconnaissance survey, 1998

The U.S. Geological Survey, in collaboration with the U.S. Environmental Protection Agency, the American Water Works Association, and the American Water Works Service Company, completed a targeted national reconnaissance survey of selected radionuclides in public ground-water supplies. Radionuclides analyzed included radium-224 (Ra-224), radium-226 (Ra-226), radium-228 (Ra-228), polonium-210 (Po-210) and lead-210 (Pb-210).This U.S. Geological Survey reconnaissance survey focused intentionally on areas with known or suspected elevated concentrations of radium in ground water to determine if Ra-224 was also present in the areas where other isotopes of radium had previously been detected and to determine the co-occurrence characteristics of the three radium isotopes (Ra-224, Ra-226, and Ra-228) in those areas. Ninety-nine raw-water samples (before water treatment) were collected once over a 6-month period in 1998 and 1999 from wells (94 of which are used for public drinking water) in 27 States and 8 physiographic provinces. Twenty-one of the 99 samples exceeded the current U.S. Environmental Protection Agency drinking-water maximum contaminant level of 5 picocuries per liter (pCi/L) for combined radium (Ra-226 + Ra-228). Concentrations of Ra-224 were reported to exceed 1 pCi/L in 30 percent of the samples collected, with a maximum concentration of 73.6 pCi/L measured in water from a nontransient, noncommunity, public-supply well in Maryland. Radium-224 concentrations generally were higher than those of the other isotopes of radium. About 5 percent of the samples contained concentrations of Ra-224 greater than 10 pCi/L, whereas only 2 percent exceeded 10 pCi/L for either Ra-226 or Ra-228. Concentrations of Ra-226 greater than 1 pCi/L were reported in 33 percent of the samples, with a maximum concentration of 16.9 pCi/L measured in water from a public-supply well in Iowa. Concentrations of Ra-228 greater than 1 pCi/L were reported in 22 samples, with a maximum concentration of 72.3 pCi/L measured in water from a non-transient, noncommunity, public-supply well in Maryland.Radium-224, which is a decay product of Ra-228 in the Th-232 decay series, was significantly correlated with Ra-228 (Spearman?s rank correlation coefficient ?r? equals 0.82) and to a lesser degree with Ra-226 (r equals 0.69), which is an isotope in the U-238 decay series. The rank correlation coefficient between Ra-226 and Ra-228 was 0.63. The high correlation between Ra-224 and Ra-228 concentrations and the corresponding isotopic ratios of the two (about 1:1 in 90 percent of the samples) indicates that the two radionuclides occur in approximately equal concentrations in most ground water sampled. Thus, Ra-228 can be considered as a reasonable proxy indicator for the occurrence of Ra-224 in ground water.The maximum concentration of Po-210 was 4.85 pCi/L and exceeded 1 pCi/L in only two samples. The maximum concentration of Pb-210 was 4.14 pCi/L, and about 10 percent of the samples exceeded 1 pCi/L. Areas with known, or suspected, elevated concentrations of polonium and lead were not targeted in this survey.Three major implications are drawn for future radionuclide monitoring on the basis of this information: (1) grossalpha particle analyses of ground water should be done within about 48-72 hours after collection to determine the presence of the short-lived, alpha-particle emitting isotopes, such as Ra-224, which was detected in elevated concentrations in many of the samples collected for this survey; (2) the isotope ratios of Ra-224 to Ra-228 in ground water are variable on a national scale, but the two radioisotopes generally occur in ratios near 1:1, therefore, the more commonly measured Ra-228 can be used as an indicator of Ra-224 occurrence for some general purposes other than compliance; and (3) the isotopic ratios of Ra-226 to Ra-228 were less than 3:2 in many samples. These ratios corroborate results of previous studies that have shown the presence of Ra-228.

Water-Resources Investigations Report↗
USGS2001

Hydrogeology of the Tully Lakes area in southern Onondaga and northern Cortland Counties, New York

Water levels in a series of kettlehole lakes and ponds known as the Tully Lakes respond to seasonal water-level changes in the surrounding aquifer but often differ from ground-water levels in the aquifer because the lakebed sediments are poorly permeable and inhibit the exchange of water. Three sets of ground-water-level measurements were made from the spring recharge period of 2000 through the fall of that year. Seasonal ground-water-level declines ranged from 1.5 to 8 feet. Average annual water-level fluctuations in the three western lakes ranged from 2.5 to 6 feet, whereas those in the two eastern lakes were only about 1.5 feet because these lakes have natural outlets. The ground-water divide between the St. Lawrence and Susquehanna River Basins did not coincide with the surface-water divide and the ground-water divide moved southerly in response to lower water levels in the aquifer during the summer and fall.

New York↗
USGS1995

Vulnerability of the uppermost ground water to contamination in the greater Denver area, Colorado

Information about vulnerability of ground water to contamination is needed to facilitate ground-water management. Vulnerability of ground water refers to the intrinsic characteristics that determine the sensitivity of the water to being adversely affected by an imposed contaminant load. Within the greater Denver area, vulnerability of the uppermost ground water to contamination from the surface was assessed by considering the intrinsic characteristics included in a method developed by the U.S. Environmental Protection Agency and the National Water Well Association, the DRASTIC method. The seven geohydrologic characteristics considered are: (1) Aquifer media, (2) hydraulic conductivity, (3) unsaturated media, (4) depth to water, (5) recharge, (6) soil media, and (7) land-surface slope. Recharge from precipitation generally is less than 2 inches per year; no effort was made to quantify the variation of recharge throughout the study area. Data for geology, depth to water, soils, and elevation were obtained and processed to produce maps of the other six characteristics. Spatial and attribute data for these maps were stored and processed by geographic-information-system software to produce a map showing vulnerability of the uppermost ground water to contamination from the surface. This report describes the assessment of each geohydrologic characteristic and the 157 vulnerability response units that were delineated within the greater Denver area. These response units are unique with respect to the geohydrologic characteristics considered. The uppermost ground water within each of the vulnerability response units are described in a series of tables, which include qualitative and selected quantitative data and the vulnerability rating assigned for each of the seven geohydrologic characteristics.

Water-Resources Investigations Report↗
USGS1994

User's guide to revised method-of-characteristics solute-transport model (MOC--version 31)

The U.S. Geological Survey computer model to simulate two-dimensional solute transport and dispersion in ground water (Konikow and Bredehoeft, 1978; Goode and Konikow, 1989) has been modified to improve management of input and output data and to provide progressive run-time information. All opening and closing of files are now done automatically by the program. Names of input data files are entered either interactively or using a batch-mode script file. Names of output files, created automatically by the program, are based on the name of the input file. In the interactive mode, messages are written to the screen during execution to allow the user to monitor the status and progress of the simulation and to anticipate total running time. Information reported and updated during a simulation include the current pumping period and time step, number of particle moves, and percentage completion of the current time step. The batch mode enables a user to run a series of simulations consecutively, without additional control. A report of the model's activity in the batch mode is written to a separate output file, allowing later review. The user has several options for creating separate output files for different types of data. The formats are compatible with many commercially available applications, which facilitates graphical postprocessing of model results. Geohydrology and Evaluation of Stream-Aquifer Relations in the Apalachicola-Chattahoochee-Flint River Basin, Southeastern Alabama, Northwestern Florida, and Southwestern Georgia By Lynn J. Torak, Gary S. Davis, George A. Strain, and Jennifer G. Herndon Abstract The lower Apalachieola-Chattahoochec-Flint River Basin is underlain by Coastal Plain sediments of pre-Cretaceous to Quaternary age consisting of alternating units of sand, clay, sandstone, dolomite, and limestone that gradually thicken and dip gently to the southeast. The stream-aquifer system consism of carbonate (limestone and dolomite) and elastic sediments, which define the Upper Floridan aquifer and Intermediate system, in hydraulic connection with the principal rivers of the basin and other surface-water features, natural and man made. Separate digital models of the Upper Flori-dan aquifer and Intermediate system were constructed by using the U.S. Geological Survey's MODular Finite-Element model of two dimensional ground-water flow, based on concep- tualizations of the stream-aquifer system, and calibrated to drought conditions of October 1986. Sensitivity analyses performed on the models indicated that aquifer hydraulic conductivity, lateral and vertical boundary flows, and pumpage have a strong influence on groundwater levels. Simulated pumpage increases in the Upper Floridan aquifer, primarily in the Dougherty Plain physiographic district of Georgia,. caused significant reductions in aquifer discharge to streams that eventually flow to Lake Seminole and the Apalachicola River and Bay. Simulated pumpage increases greater than 3 times the October 1986 rates caused drying ofsome stream reaches and parts of the Upper Floridan aquifer in Georgia. Water budgets prepared from simulation results indicate that ground- water discharge to streams and recharge by horizontal and vertical flow are the principal mechanisms for moving water through the flow system. The potential for changes in ground-water quality is high in areas where chemical constituents can be mobilized by these mechanisms. Less than 2 percent of ground-water discharge to streams comes from the Intermediate system; thus, it plays a minor role in the hydrodynamics of the stream- aquifer system.

Water-Resources Investigations Report↗
USGS1995

Geohydrology and vertical distribution of volatile organic compounds in ground water, Fischer and Porter Company Superfund Site, Warminster, Bucks County, Pennsylvania

The Fischer and Porter Company Superfund Site is underlain by sedimentary rocks of the Upper Triassic Stockton Formation, which consists of interbedded siltstone, very-fine grained to coarse-grained sandstone, and conglomerate in crudely defined, upward fining cycles. These rocks form a complex, heterogeneous, leaky, multiaquifer system comprised of a series of gently dipping lithologic units with different hydraulic properties. Ground water is unconfined in the shallower part of the aquifer and confined or semiconfined in the deeper part of the aquifer. Water levels measured in monitor well clusters and borehole-flow measurements made in open boreholes show a downward hydraulic head gradient at the site, caused in part by the pumping of nearby, deep public-supply wells and the Fischer and Porter treatment system extraction wells. Downward borehole flow was measured at rates up to 9 gallons per minute. Aquifer-isolation tests were run in the six boreholes to obtain depth-discrete specific-capacity and water-quality data. On the basis of specific-capacity data for 27 isolated intervals, specific capacity is not related to depth. Water levels in monitor wells at the Fischer and Porter Site are greatly affected by the pumping of nearby public-supply wells, as well as the pumping of the Fischer and Porter treatment system extraction wells. Pumping of the public-supply wells causes daily water-level fluctuations in wells at the site as great as 5.3 feet. The shutdown of the Fischer and Porter treatment system extraction wells caused a rise in water level in all wells screened in the intermediate and deep zones. The rise in water level was as great as 4.3 feet in the intermediate zone and as great as 5.9 feet in the deep zone. The direction of ground-water flow is toward the north in the shallow and intermediate zones and toward the west and west-southwest in the deep zone. Ground-water discharge probably is to the unnamed tributary to Pennypack Creek north and west of the site. Volatile organic compounds (VOC's) were detected in most depth-discrete water samples. No general trend of increasing or decreasing concentrations of VOC's with depth were observed, and none of the isolated intervals had highly elevated concentrations of VOC's. Observed fairly constant concentrations of VOC's with depth are the result of the downward head gradient and the former presence of open boreholes on the site. The downward head gradient and pumping of nearby, deep public-supply wells caused the vertical migration and outward movement of VOC's into the aquifer through former supply and monitor wells of open-hole construction in the main area of contamination.

Pennsylvania↗
USGS1996

Geohydrology, water levels and directions of flow, and occurrence of light-nonaqueous-phase liquids on ground water in northwestern Indiana and the Lake Calumet area of northeastern Illinois

A study was performed by the U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, to describe the geohydrology and distribution of light-nonaqueousphase liquids in an industrialized area of northwestern Indiana and northeastern Illinois. The geologic units of concern underlying this area are the carbonates of the Niagaran Series, the Detroit River and Traverse Formations; the Antrim Shale; and sands, silts, and clays of Quaternary age. The hydrologic units of concern are surface water, the Calumet aquifer, the confining unit, and the Silurian-Devonian aquifer. Water levels collected in June 1992 indicate that the water-table configuration generally is a subdued reflection of topography. Recharge from landfill leachate and ponded water, discharge to sewers, and pumping also affect the water-table configuration. A depression in the potentiometric surface of the Silurian-Devonian aquifer results from pumping. Light-nonaqueous-phase liquids were detected near petroleum handling, industrial and waste-disposal facilities. Horizontal ground-water velocity at the water table in the confining unit ranged from 4.4x10 -4 to 1.0x10 -3 feet per day. Horizontal ground-water velocity in the Calumet and Silurian-Devonian aquifers ranged from 1.0x10 -2 to 3.4x10 -1 and from 1.4x10 -2 to 2.9x10 -2 feet per day, respectively. Vertical hydraulic gradients indicate generally downward flow from the Calumet aquifer into the confining unit, then into the Silurian-Devonian aquifer. Calculated vertical groundwater velocity through the weathered and unweathered parts of the confining unit are 3.8x10 -2 and 1.5x10 -3 feet per day, respectively.

Illinois, Indiana↗
USGS1996

Geohydrologic reconnaissance of Lake Mead National Recreation Area: Las Vegas Wash to Virgin River, Nevada

This study is the last of a series of eight geohydrologic reconnaissance studies that were done in the Lake Mead National Recreation Area. The studies were done to evaluate the water resources in the recreation area and to identify areas having potential for the development of water supplies that would be adequate for marinas and campgrounds. The study area includes about 250 square miles north of Lake Mead from Las Vegas Wash to the Virgin River (Overton Arm), Nevada. Volcanic rocks, consolidated sedimentary rocks, and unconsolidated to semiconsolidated sedimentary rocks underlie the area. Surface-water sources include the Colorado River, Virgin River, Muddy River, and Las Vegas Wash. Elsewhere in the area, streamflow is meager and extremely variable. Ground water originates from four sources: (1) subsurface flow in local basins, (2) infiltration of water from Lake Mead into permeable rocks near the lake, (3) subsurface flow in valleys of perennial streams, and (4) subsurface flow in consolidated rocks of the Muddy Mountains. The quantity of water from Lake Mead that has saturated rocks adjacent to the lake probably is greater than the quantity of ground water from all the other sources. Rocks saturated by water from the lake probably extend less than 0.5 mile inland from the lake shore. The quality of virtually all the ground water in the area is not acceptable for drinking purposes. The most favorable areas for obtaining ground water are those underlain by the coarse-grained deposits of the older alluvium and the younger alluvium adjacent to Lake Mead. The least favorable areas are those underlain by the mudstone facies of the Muddy Creek Formation and fine-grained rocks of the Horse Spring Formation. Four areas identified as having potential for ground-water development are (1) near Overton Beach, (2) west of Callville Bay, (3) near Middle Point, and (4) in the lower Moapa Valley. Usable quantities of water probably can be obtained at these sites, but the quality of the water may not be acceptable for drinking purposes. Test drilling for potable water supplies should be considered only as exploration.

Nevada↗
USGS1996

Geohydrology of the Stockton Formation and cross-contamination through open boreholes, Hatboro Borough and Warminster Township, Pennsylvania

The study area consists of a 9-square-mile area underlain by sedimentary rocks of the middle arkose member of the Stockton Formation of Upper Triassic age. In the Hatboro area, the Stockton Formation strikes approximately N. 65 degrees E. and dps approximately 9 degrees NW. The rocks are chiefly arkosic sandstone and siltstone. Rocks of the Stocton Formation form a complex, heterogeneous, multiaquifer system consisting of a series of gently dipping lithologic units with different hydraulic properties. Most ground water in the unweathered zone moves through a network of interconnecting secondary openigns-fractures, bedding plans, and joints. Ground water is unconfined in the shallower part of the aquifer and semiconfined or confined in the deeper part of the aquifer. Nearly all deep wells in the Stockton Formation are open to several water-bearing zones and are multiaquifer wells. Each water-bearing zone usually has a different hydraulic head. Where differences in hydraulic head exist between water-bearing zones, water in the well bore flows under nonpumping conditions in the direction of decreasing head. Determination of the potential for borehole flow was based on caliper, natural-gamma, single- point-resistance, fluid-resistivity, and (or) fluid-temperature logs that were run in 162 boreholes 31 to 655 feet deep. The direction and rate of borehole-fluid movement were determined in 83 boreholes by the bring-tracing method and in 10 boreholes by use of a heat-pulse flowmeter. Borehole flow was measurable in 65 of the 93 boreholes (70 percent). Fluid movement at rates up to 17 gallons per minute was measured. Downward flow was measured in 36 boreholes, and upward flow was measured in 23 boreholes, not including those boreholes in which two directions of flow were measured. Both upward and downward vertical flow was measured in six boreholes; these boreholes are 396 to 470 feet deep and were among the deepest boreholes logged. Fluid movement was upward in the upper part of the borehole and downward in the lower part of the borehole in two boreholes. Fluid movement wad downward in the upper part of the borehole and upward in the lower part of the borehole in three boreholes. Groung-water contamination by volatile organic compounds (VOC's) is widespread in the study area. Detectable concentrations of VOC's were present in water samples from 24 wells sampled in Hatboro Brough and in water samples for 10 of 14 wells (71 percent) samples in Warminster Township. Samples of borehole flow from nine boreholes in the industrial area of Hatboro were collected for laboratory analysis to estimate the quantity of VOC's in borehole flow. Downward flow was measured in all of these boreholes. Concentrations of TCE, TCA, and 1,1-DCE as great at 5,800, 1,400 and 260 micrograms per liter, respectively, show that some water moving downward in the aquifer through these open boreholes is highly contaminated and that open boreholes may contribute substantially to ground-water contamination. An estimated 14.7 gallons per year of VOC's were moving downward through the nine open boreholes sampled from the contaminated, upper part of the aquifer to the lower part, which is tapped by public supply wells. Borehole geophysical logs were used as a guide to design and construct monitor-well networks at three National Priorities List sites in the area. An open borehole was dirlled, and a suite of geophysical logs was run. Interpretation of geophysical logs enabled the identification of water-bearing zones that produce and receive water; these are zones that should not be connected. From the logs, discrete intervals to be monitored were selected. In the Stockton Formation, the same water-bearing zone may not be intersected in adjacent boreholes, especially if it is a vertical fracture with a diffident magnetic orientation than that of the adjacent boreholes. In most areas of the stockton Formation, depth of water-bearing zones in an are

Pennsylvania↗