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At least 1,387 records · Page 77Linked to original sources
USGS1973

Ground-water basic data for Griggs and Steele Counties, North Dakota

The objectives of the hydrologic investigation in Griggs and Steele Counties, N. Dak. (fig. 1) were to: (1) determine the location, extent, and nature of the major aquifers; (2) evaluate the occurrence and movement of ground water, including recharge and discharge; (3) estimate the quantities of water stored in the aquifers; (4) estimate the potential yields of wells tapping the major aquifers; and (5) determine the chemical quality of the ground water.

North Dakota↗
USGS2002

A three-dimensional numerical model of predevelopment conditions in the Death Valley regional ground-water flow system, Nevada and California

In the early 1990's, two numerical models of the Death Valley regional ground-water flow system were developed by the U.S. Department of Energy. In general, the two models were based on the same basic hydrogeologic data set. In 1998, the U.S. Department of Energy requested that the U.S. Geological Survey develop and maintain a ground-water flow model of the Death Valley region in support of U.S. Department of Energy programs at the Nevada Test Site. The purpose of developing this 'second-generation' regional model was to enhance the knowledge an understanding of the ground-water flow system as new information and tools are developed. The U.S. Geological Survey also was encouraged by the U.S. Department of Energy to cooperate to the fullest extent with other Federal, State, and local entities in the region to take advantage of the benefits of their knowledge and expertise. The short-term objective of the Death Valley regional ground-water flow system project was to develop a steady-state representation of the predevelopment conditions of the ground-water flow system utilizing the two geologic interpretations used to develop the previous numerical models. The long-term objective of this project was to construct and calibrate a transient model that simulates the ground-water conditions of the study area over the historical record that utilizes a newly interpreted hydrogeologic conceptual model. This report describes the result of the predevelopment steady-state model construction and calibration. The Death Valley regional ground-water flow system is situated within the southern Great Basin, a subprovince of the Basin and Range physiographic province, bounded by latitudes 35 degrees north and 38 degrees 15 minutes north and by longitudes 115 and 118 degrees west. Hydrology in the region is a result of both the arid climatic conditions and the complex geology. Ground-water flow generally can be described as dominated by interbasinal flow and may be conceptualized as having two main components: a series of relatively shallow and localized flow paths that are superimposed on deeper regional flow paths. A significant component of the regional ground-water flow is through a thick Paleozoic carbonate rock sequence. Throughout the flow system, ground water flows through zones of high transmissivity that have resulted from regional faulting and fracturing. The conceptual model of the Death Valley regional ground-water flow system used for this study is adapted from the two previous ground-water modeling studies. The three-dimensional digital hydrogeologic framework model developed for the region also contains elements of both of the hydrogeologic framework models used in the previous investigations. As dictated by project scope, very little reinterpretation and refinement were made where these two framework models disagree; therefore, limitations in the hydrogeologic representation of the flow system exist. Despite limitations, the framework model provides the best representation to date of the hydrogeologic units and structures that control regional ground-water flow and serves as an important information source used to construct and calibrate the predevelopment, steady-state flow model. In addition to the hydrogeologic framework, a complex array of mechanisms accounts for flow into, through, and out of the regional ground-water flow system. Natural discharges from the regional ground-water flow system occur by evapotranspiration, springs, and subsurface outflow. In this study, evapotranspiration rates were adapted from a related investigation that developed maps of evapotranspiration areas and computed rates from micrometeorological data collected within the local area over a multiyear period. In some cases, historical spring flow records were used to derive ground-water discharge rates for isolated regional springs. For this investigation, a process-based, numerical model was developed to estimat

Water-Resources Investigations Report↗
USGS1983

Water-resources investigations of the U.S. Geological Survey in the Souris-Red Rivers basin in Minnesota, North Dakota, and South Dakota

Information obtained on water resources by Federal and State agencies in the Souris-Red Rivers basin along the Canadian border in the midwestern United States is available for analysis to address flood, drought, and supply problems. It consists of streamflows, ground water measurements, and quality of water determinations. This summary contains locations of data sites; lists of current and past studies with titles, objectives, locations, and dates; and available water resources reports. Listed are 46 projects and investigations; 233 active and 145 inactive streamflow gages; 198 active and 252 inactive surface water quality sites; 457 active and 49 inactive ground water level observation wells, some of which are water quality sampling sites; and 252 reports. Four maps are included as an aid in locating the sites.

Minnesota, North Dakota, South Dakota↗
USGS1987

The effects of boundary conditions on the steady-state response of three hypothetical ground-water systems; results and implications of numerical experiments

The most critical and difficult aspect of defining a groundwater system or problem for conceptual analysis or numerical simulation is the selection of boundary conditions . This report demonstrates the effects of different boundary conditions on the steady-state response of otherwise similar ground-water systems to a pumping stress. Three series of numerical experiments illustrate the behavior of three hypothetical groundwater systems that are rectangular sand prisms with the same dimensions but with different combinations of constant-head, specified-head, no-flow, and constant-flux boundary conditions. In the first series of numerical experiments, the heads and flows in all three systems are identical, as are the hydraulic conductivity and system geometry . However, when the systems are subjected to an equal stress by a pumping well in the third series, each differs significantly in its response . The highest heads (smallest drawdowns) and flows occur in the systems most constrained by constant- or specified-head boundaries. These and other observations described herein are important in steady-state calibration, which is an integral part of simulating many ground-water systems. Because the effects of boundary conditions on model response often become evident only when the system is stressed, a close match between the potential distribution in the model and that in the unstressed natural system does not guarantee that the model boundary conditions correctly represent those in the natural system . In conclusion, the boundary conditions that are selected for simulation of a ground-water system are fundamentally important to groundwater systems analysis and warrant continual reevaluation and modification as investigation proceeds and new information and understanding are acquired.

Water Supply Paper↗
USGS2010

A Compilation of Spatial Datasets and Surface-Water and Ground-Water Data from the U.S. Geological Survey and Other Federal and Oklahoma State Agencies for the Kickapoo Tribe of Oklahoma

This report contains spatial datasets of natural and anthropogenic features and spatial datasets detailing surface-water, ground-water, and other types of environmental information collected in and surrounding Kickapoo Tribal Lands. Spatial datasets were compiled from Federal and Oklahoma State agencies. Surface-water, ground-water, and other types of environmental information of natural and anthropogenic features were compiled from USGS National Water Information System database, Oklahoma Department of Environmental Quality online Geographic Information System data viewer, Oklahoma Water Resources Board online Water Information Mapping System, and U.S. Environmental Protection Agency online Modernized STORET database. These spatial datasets were compiled from many different sources with varying quality. Because of the different sources, features common to multiple layers may not overlay exactly. Users should check the metadata to determine proper use of these data. These data were not checked for accuracy or completeness. Should a question of accuracy or completeness arise, the user should contact the originator cited in the metadata.

Data Series↗
USGS2002

Changes in ground-water quality in the Canal Creek Aquifer between 1995 and 2000-2001, West Branch Canal Creek area, Aberdeen Proving Ground, Maryland

Since 1917, Aberdeen Proving Ground, Maryland has been the primary chemical-warfare research and development center for the U.S. Army. Ground-water contamination has been documented in the Canal Creek aquifer because of past disposal of chemical and ordnance manufacturing waste. Comprehensive sampling for volatile organic compounds in ground water by the U.S. Geological Survey in the West Branch Canal Creek area was done in June?October 1995 and June?August 2000. The purpose of this report is (1) to compare volatile organic compound concentrations and determine changes in the ground-water contaminant plumes along two cross sections between 1995 and 2000, and (2) to incorporate data from new piezometers sampled in spring 2001 into the plume descriptions. Along the southern cross section, total concentrations of volatile organic compounds in 1995 were determined to be highest in the landfill area east of the wetland (5,200 micrograms per liter), and concentrations were next highest deep in the aquifer near the center of the wetland (3,300 micrograms per liter at 35 feet below land surface). When new piezometers were sampled in 2001, higher carbon tetrachloride and chloroform concentrations (2,000 and 2,900 micrograms per liter) were detected deep in the aquifer 38 feet below land surface, west of the 1995 sampling. A deep area in the aquifer close to the eastern edge of the wetland and a shallow area just east of the creek channel showed declines in total volatile organic compound concentrations of more than 25 percent, whereas between those two areas, con-centrations generally showed an increase of greater than 25 percent between 1995 and 2000. Along the northern cross section, total concentrations of volatile organic compounds in ground water in both 1995 and 2000 were determined to be highest (greater than 2,000 micrograms per liter) in piezometers located on the east side of the section, farthest from the creek channel, and concentrations were progressively lower at piezometer locations closer to the creek channel. Total volatile organic compound concentrations increased more than 25 percent in some areas in the middle depths of the aquifer; however, it could not be determined if a defined plume was moving farther downgradient along ground-water flow paths toward the creek channel, or vertically downward because of density differences within the aquifer.

Water-Resources Investigations Report↗
USGS1981

Water-resources investigations of the U.S. Geological Survey in Wyoming, fiscal year 1980

This report contains lists and location maps of streamflow and reservoir stations, ground-water stations, water-quality stations, sediment stations, and peak-flow partial-record stations that are currently being operated in Wyoming. Water-resources appraisal projects are also described, including many that are related to development of energy resources. The general locations of the projects are shown on maps. The U.S. Geological Survey is striving to coordinate its water-resources investigations with those of other agencies. This report is one phase of that coordination effort and serves as an annual progress report to cooperators and the public. (USGS)

Open-File Report↗
USGS1972

Progress report: Apollo 16 sample documentation

This report is intended as a working document for use during the opening of the Apollo 16 sample containers and during the early phases of examination of the samples in the Lunar Receiving Laboratory (LRL). The information in this report was drawn from voice transcripts of the astronaut crew while on the lunar surface, from video tapes of lunar surface television, and from a "quick-look" at the returned 60 mm Hasselblad photographs. The planimetric station maps were compiled almost entirely from the television tapes. A thorough review of all data, plus a comparison of the rocks shown in the photographs with those in the LRL, should eliminate any errors or discrepancies. A major purpose of this document is, in fact, to point up gaps in our present knowledge of sample location, orientation, and documentation. This report will be superseded by a more accurate and complete report about two weeks hence. All sample numbers in the illustrations refer to container numbers. Those that have LRL numbers assigned as of this date are cross-referenced in table 1. The illustrations are grouped in order of ascending station numbers (fig. 1), and where possible are shown in order of ascending container numbers for each station. Table 1 also refers container numbers to pane numbers of this report.

Open-File Report↗
USGS1973

Documentation and environment of the Apollo 17 samples

This catalog shows the locations from which samples were collected during the Apollo 17 mission and provides a descriptive geologic context for each sample. It is a working document principally of use to LSPET, LSAPT, and the lunar sample principal investigators. The information in this report is incomplete, but it is based on the best available data as of January 19, 1973. Sources of information are: air-to-ground transcript, lunar surface television, lunar surface photographs, available LRL "mugshot" photographs of the samples, and frequent discussions with the astronaut crew. The information contained herein does not reflect the more detailed examination that is presently underway in the LRL. Documentation of some samples at the Apollo 17 site is incomplete. Identification of the rocks on the photographs is tentative in many cases pending examination of the samples under collimated light and accurate determination of lunar orientation. These data will be incorporated in a final report on sample documentation. There are inconsistencies in format (and even errors), but we believe that the early dissemination of these data is more important than the complete standardization of format which would require detailed editing and substantial delay. Nearly all of the sizes, distances, slopes, and percentages given are qualitative, visual estimates from photographs. The station maps (the fold-outs in back of the report) were compiled using a perspective grid overlay on the photographs, and thus are more accurate than most other dimensional data in this catalog. The station descriptions that follow this introduction apply to the general station area (see figure on next page); the environment descriptions under each sample apply to an area a few meters on a side around each sample, and may or may not reflect the surface characteristics of the entire station area. Some of the LRL numbers (supplied courtesy of Patrick Burler, Assistant Curator, Lunar Receiving Laboratory, NASA-MSC) are still tentative and subject to change as more sample containers are opened. The tentative numbers are indicated by an asterisk after the number. Photograph numbers throughout the text normally have the following prefix: NASA AS17- which is deleted for brevity in this report.

Open-File Report↗
USGS1975

A Study of earthquake losses in the Puget Sound, Washington, area

The Puget Sound Basin has a history of frequent seismic activity, including two recent damaging events. The greatest extent of urban development and the most densely populated area generally correspond to the area where the greatest energy release has been experienced. For this study two earthquakes have been simulated, each having magnitude 7.5, a reasonable maximum value for this area. Analysis of the events indicate that under the worst condition as many as 2,200 people would die, and 8,700 additional persons would suffer injuries requiring hospitalization or immediate medical treatment. Such casualties would occur under the worst conditions of exposure, as during the rush hours, but could be approximately as great at any time during the working day. It is possible that as many as 23,500 people would be homeless or would require temporary shelter pending reestablishment or relocation. Conditions of exposure would be altered during the nighttime, causing a drastic reduction in casulaty potentials to a level of about 5-10 percent of the daytime losses. Thus, the time of greatest concern is during the normal working day, and the areas of concern are the highly urbanized sections of the Puget Sound Basin. This study is intended to inform those agencies serving the region of potential hazard to people, structures, and lifeline functions, in such a way that the administrators of emergency services can proceed with confidence in planning response to earthquake disaster. Figure 1 shows the extent of the study area and the location of the epicenters of the postulated earthquakes. A comparison of the two isoseismal maps as they apply to each county, in tables 1 through 6, emphasizes the marked change in intensity at a site as the simulated earthquake is moved from a close to a distant location. The Modified Mercalli Intensity scale is defined on page 284. The report is concerned not only with human casualties and displacement, but also with impairment or destruction of essential facilities critical to the continuing normal functioning of the area. This includes hospitals and medical personnel, police and fire department equipment and personnel, communications, and utilities. The total damage profile was developed with careful consideration of conditions of the seismicity, geological history, population density and distribution, and physical status of structural and lifeline installations throughout the region. There is a potential for broad fluctuation in the casualty figures resulting from the chance positioning of people at the time of the occurrence of the earthquake. An example is that of the Lafayette Elementary School in West Seattle, where, in the 1949 earthquake, a large brick gable over the entry collapsed directly onto an area normally used for assembly of pupils. Such assembly regularly occurred at 11:55 a.m. The earthquake occurred at 11:57 a.m., but fortunately during the spring vacation. Following a large earthquake, effective remedial steps to maintain or to return to operation the essential public services will depend upon the prompt and informed actions of public agencies. Response planning should include not only consideration of disaster problems within a particular jurisdiction but also sharing of assistance with neighboring jurisdictions. Moderate response requirements experienced in one area can free resources to aid communities in more heavily damaged portions of the affected area. The damage profile is quite different among the six counties within the study. The remainder of the summary is devoted to a brief general assessment of possible problems in each of the counties. A detailed development and presentation of each of the problems is covered in the text of the report.

Washington↗
USGS1966

Flood of October 8, 1962, on Bachman Branch and Joes Creek at Dallas, Texas

This report presents hydrologic data that enable the user to define areas susceptible to flooding and to evaluate the flood hazard along Bachman Branch and Joes Creek. The data provide a technical basis for making sound decisions concerning the use of flood-plain lands. The report will be useful for preparing building and zoning regulations, locating waste disposal facilities, purchasing unoccupied land, developing recreational areas, and managing surface water in relation to ground-water resources. This is one of the series of reports delineating the flood hazard on streams in the Dallas area.

Texas↗
USGS1990

Computerized stratified random site-selection approaches for design of a ground-water-quality sampling network

Computer software was written to randomly select sites for a ground-water-quality sampling network. The software uses digital cartographic techniques and subroutines from a proprietary geographic information system. The report presents the approaches, computer software, and sample applications. It is often desirable to collect ground-water-quality samples from various areas in a study region that have different values of a spatial characteristic, such as land-use or hydrogeologic setting. A stratified network can be used for testing hypotheses about relations between spatial characteristics and water quality, or for calculating statistical descriptions of water-quality data that account for variations that correspond to the spatial characteristic. In the software described, a study region is subdivided into areal subsets that have a common spatial characteristic to stratify the population into several categories from which sampling sites are selected. Different numbers of sites may be selected from each category of areal subsets. A population of potential sampling sites may be defined by either specifying a fixed population of existing sites, or by preparing an equally spaced population of potential sites. In either case, each site is identified with a single category, depending on the value of the spatial characteristic of the areal subset in which the site is located. Sites are selected from one category at a time. One of two approaches may be used to select sites. Sites may be selected randomly, or the areal subsets in the category can be grouped into cells and sites selected randomly from each cell.

Water-Resources Investigations Report↗
USGS2000

Data from a thick unsaturated zone underlying Oro Grande and Sheep Creek washes in the western part of the Mojave Desert, near Victorville, San Bernardino County, California

This report presents data on the physical properties of unsaturated alluvial deposits and on the chemical and isotopic composition of soil water and soil gas collected at 12 monitoring sites in the western part of the Mojave Desert, near Victorville, California. Sites were installed using the ODEX air-hammer method. Seven sites were located in the active channels of Oro Grande and Sheep Creek Washes. The remaining five sites were located away from the active washes. Most sites were drilled to a depth of about 100 feet below land surface; two sites were drilled to the water table almost 650 feet below land surface. Drilling procedures, lithologic and geophysical data, and site construction and instrumentation are described. Core material was analyzed for water content, bulk density, water potential, particle size, and water retention. The chemical composition of leachate from almost 1,000 subsamples of cores and cuttings was determined. Water extracted from selected subsamples of cores was analyzed for tritium and the stable isotopes of oxygen and hydrogen. Water from suction-cup lysimeters and soil-gas samples also were analyzed for chemical and isotopic composition. In addition, data on the chemical and isotopic composition of bulk precipitation from five sites and on ground water from two water-table wells are reported.

California↗
USGS2007

Ground-water, surface-water, and water-chemistry data, Black Mesa area, northeastern Arizona— 2005-06

The N aquifer is the major source of water in the 5,400 square-mile Black Mesa area in northeastern Arizona. Availability of water is an important issue in northeastern Arizona because of continued water requirements for industrial and municipal use and the needs of a growing population. Precipitation in the Black Mesa area averages about 6 to 14 inches per year. The water monitoring program in the Black Mesa area began in 1971 and is designed to provide information about the long-term effects of ground-water withdrawals from the N aquifer for industrial and municipal uses. This report presents results of data collected for the monitoring program in the Black Mesa area from January 2005 to September 2006. The monitoring program includes measurements of (1) ground-water pumping, (2) ground-water levels, (3) spring discharge, (4) surface-water discharge, (5) ground-water chemistry, and (6) periodic testing of ground-water withdrawal meters. In 2005, ground-water withdrawals in the Black Mesa area totaled 7,330 acre-feet, including ground-water withdrawals for industrial (4,480 acre-feet) and municipal (2,850 acre-feet) uses. From 2004 to 2005, total withdrawals increased by less than 2 percent, industrial withdrawals increased by approximately 3 percent, and total municipal withdrawals increased by 0.35 percent. From 2005 to 2006, annually measured water levels in the Black Mesa area declined in 10 of 13 wells in the unconfined areas of the N aquifer, and the median change was -0.5 foot. Measurements indicated that water levels declined in 12 of 15 wells in the confined area of the aquifer, and the median change was -1.4 feet. From the prestress period (prior to 1965) to 2006, the median water-level change for 29 wells was -8.5 feet. Median water-level changes were -0.2 foot for 13 wells in the unconfined areas and -46.6 feet for 16 wells in the confined area. Ground-water discharges were measured once in 2005 and once in 2006 at Moenkopi School Spring and Burro Spring. Discharge decreased by 3.5 percent at Moenkopi School Spring and by 15 percent at Burro Spring. During the period of record at each spring, discharges fluctuated; a decreasing trend was apparent. Continuous records of surface-water discharge in the Black Mesa area have been collected from streamflow gages at the following sites: Moenkopi Wash (1976 to 2005), Dinnebito Wash (1993 to 2005), Polacca Wash (1994 to 2005), Pasture Canyon Spring (August 2004 to December 2005), and Laguna Creek (1996 to 2005). Median flows during November, December, January, and February of each water year were used as an index of the amount of ground-water discharge to the above named sites. For the period of record at each streamflow-gaging station, the median winter flows have decreased for Moenkopi Wash, Dinnebito Wash, and Polacca Wash. There is not a long enough period of record for Pasture Canyon Spring and Laguna Creek was discontinued at the end of December 2005. In 2006, water samples were collected from 6 wells and 2 springs in the Black Mesa area and analyzed for selected chemical constituents. Dissolved-solids concentrations ranged from 111 to 588 milligrams per liter. Water samples from 5 of the wells and both of the springs had less than 500 milligrams per liter of dissolved solids. Trends in the chemistry of water samples from the 6 wells show the Pi?on NTUA 1 and Peabody 9 wells increasing in dissolved solids, Forest Lake NTUA 1 and Peabody 2 wells decreasing in dissolved solids, and Kykotsmovi PM2 and Keams Canyon PM2 wells show a steady trend. Increasing trends in dissolved-solids, chloride, and sulfate concentrations were evident from the more than 11 years of data for the 2 springs.

Arizona↗
USGS2006

Hydrology, description of computer models, and evaluation of selected water-management alternatives in the San Bernardino area, California

The San Bernardino area of southern California has complex water-management issues. As an aid to local water managers, this report provides an integrated analysis of the surface-water and ground-water systems, documents ground-water flow and constrained optimization models, and provides seven examples using the models to better understand and manage water resources of the area. As an aid to investigators and water managers in other areas, this report provides an expanded description of constrained optimization techniques and how to use them to better understand the local hydrogeology and to evaluate inter-related water-management problems. In this report, the hydrology of the San Bernardino area, defined as the Bunker Hill and Lytle Creek basins, is described and quantified for calendar years 1945-98. The major components of the surface-water system are identified, and a routing diagram of flow through these components is provided. Annual surface-water inflow and outflow for the area are tabulated using gaged measurements and estimated values derived from linear-regression equations. Average inflow for the 54-year period (1945-98) was 146,452 acre-feet per year; average outflow was 67,931 acre-feet per year. The probability of exceedance for annual surface-water inflow is calculated using a Log Pearson Type III analysis. Cumulative surface-water inflow and outflow and ground-water-level measurements indicate that the relation between the surface-water system and the ground-water system changed in about 1951, in about 1979, and again in about 1992. Higher ground-water levels prior to 1951 and between 1979 and 1992 induced ground-water discharge to Warm Creek. This discharge was quantified using streamflow measurements and can be estimated for other time periods using ground-water levels from a monitoring well (1S/4W-3Q1) and a logarithmic-regression equation. Annual wastewater discharge from the area is tabulated for the major sewage and power-plant facilities. More...

Open-File Report↗
USGS1983

Artificial recharge in the northern part of Chino ground-water basin, upper Santa Ana Valley, California

This study was made to help management design and implement a recharge-recapture system for State Water Project water in Chino Basin. Nine test holes were drilled in the study area. Analyses of data from these test holes and drillers ' logs of water wells indicate the presence of clay deposits. The clay deposits cannot be correlated between holes which indicates that they are in the form of discontinuous beds or lenses. The existence and location of two ground-water barriers (Barrier ' J ' and Red Hill Barrier) have been postulated in previous reports. Water-level data indicate that Barrier ' J ' is probably not effectively stopping the movement of ground water. Data are insufficient to determine the effectiveness of the Red Hill barrier. Five existing recharge facilities in the study area were previously constructed to control floodflow. Infiltration tests were conducted at three of the facilities, and results of these tests indicate infiltration rates of 2.6 feet per day at Day Creek, 2.0 feet per day at East Etiwanda, and 1.3 feet per day at San Sevaine. A total of about 9,000 acre-feet of State Water Project water was recharged between June 1980 and July 1981. Rising water levels in wells indicate that recharge water is percolating down to the water table. (USGS)

Water-Resources Investigations Report↗
USGS1983

Effect of urbanization on the water resources of Warminster Township, Bucks County, Pennsylvania

Rapid suburban development occurred in Warminster Township and the surrounding area after World War II, resulting in a large population dependent on ground water. In 1980, approximately 2.7 billion gallons of ground water was pumped by public water suppliers and government facilities. Pumping wells can cause drawdown as far as 2,500 feet undip, downdip, or along strike even if the wells do not penetrate the same strata. Pumping wells have lowered base flow; a stream-gain-and-loss study showed that water lost from Little Neshaminy Creek was about 60 percent of the water pumped from wells near the stream. Net ground-water infiltration to sewers was about 830 million gallons in 1979, a wet year, and about 250 million gallons in 1980, a dry year. Estimated water budgets for 1979 and 1980 indicate evapotranspiration can range from 20 to 26 inches per year (1.0 to 1.2 million gallons per day per square mile) and recharge can range from 8 to 18 inches per year (0.4 to 0.9 million gallons per day per square mile). In a year with average precipitation (45 inches or 2.1 million gallons per day per square mile), evapotranspiration is about 24 inches (1.1 million gallons per day per square mile). Ground-water development in the area influenced by pumping is at its practical limit for years of average recharge, but as much as 1.1 million gallons per day of additional water may be obtained by drilling and pumping wells in areas of Warminster Township not affected by pumping. The concentration of most dissolved constituents increased in water from seven wells, sampled at the onset of urbanization in 1953 and 1956 and again in 1979. Ground-water contamination by volatile organic compounds, especially trichloroethylene and tetrachloroethylene, has made water from some wells unsuitable for public supply. The concentration of lead in 26 samples of ground water ranged from 0 to 55 micrograms per liter, with a median of 17 micrograms per liter; this is above the reported national median and the median in nearby Chester County. High concentrations of sulfate and dissolved solids in ground water are probably caused by restricted gournd-water circulation and may be reduced by long-term pumping, which flushes the aquifer. Effluent from sewage treatment plants has degraded the quality of low streamflow.

Pennsylvania↗
USGS1994

Ground-water conditions in Georgia, 1993

Ground-water conditions during 1993 and recent ground-water level and quality trends in Georgia were evaluated using data from precipitation, ground-water, and ground-water quality monitoring networks. Data for 1993 included in this report are from precipitation records from 10 National Weather Service stations, continuous water-level records from 72 wells, and chloride analyses from 13 wells. Annual mean ground-water levels in Georgia in 1993 ranged from about 3.2 feet higher to about 9.6 feet lower than in 1992. Of the 72 wells summarized in this report, 30 wells had annual mean water levels that were higher and 42 wells had annual mean water levels that were lower in 1993 than in 1992. Record-high daily mean water levels were recorded in one well tapping the surficial aquifer, one well tapping the Upper Floridan aquifer, one well tapping the Claiborne aquifer, and one well tapping the crystalline- rock aquifers. These record highs were from about 0.1 to 0.7 feet higher than previous record highs. Record-low daily mean water levels were recorded in one well tapping the surficial aquifer, two wells tapping the Upper Floridan aquifer, four wells tapping the Cretaceous aquifer, one well tapping the Dublin-Midville aquifer system, and one well tapping the crystalline-rock aquifers. These record lows were from about 0.1 foot to 7.2 feet lower than the previous record lows. Chloride concentration in water from the Upper Floridan aquifer in most of coastal Georgia was below drinking water standards established by the Georgia Department of Natural Resources and the U.S. Environmental Protection Agency and has not changed appreciably with time. However, chloride concentration in water from some wells that tap the Floridan aquifer system in the Brunswick area exceeds the drinking water standards.

Georgia↗