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At least 469 records · Page 26Linked to original sources
USGS1995

Estimated natural ground-water recharge, discharge, and budget for the Dixie Valley area, west-central Nevada

The Dixie Valley area includes seven valleys in west-central Nevada (Dixie, Fairview, Stingaree, Cowkick, Eastgate, Pleasant, and Jersey Valleys; total, 2,380 square miles). Dixie Valley receives surface-water and ground-water flow from Stingaree, Cowkick, Eastgate, Pleasant, and Jersey Valleys and subsurface flow from Fairview Valley, which is a topographically closed basin. The relation between precipitation and altitude was re-evaluated for the Dixie Valley area using new data, and empirical estimates of recharge were revised accordingly. The revised estimate of total recharge is 23,000 acre-feet per Re-evaluation of ground-water discharge focused on Dixie Valley as the largest basin in the study area. Phreatophytic vegetation was mapped and partitioned into nine zones on the basis of species composition and foliage density. For woody phreatophytes, annual evapotranspiration rates of 0.7 cubic feet of water per cubic foot of foliage for greasewood and 1.1 cubic feet of water per cubic foot of foliage for rabbitbrush were adapted from lysimeter studies near Winnemucca, Nevada. These rates were multiplied by the foliage density of the respective phreatophytes in each zone to estimate a specific rate for that zone. Rates for salt-grass (0.5 to 0.8 foot per year) and the playa surface (0.1 to 0.3 foot per year) were based on a range of rates. used in other recent studies in western and central Nevada. These rates were multiplied by the areas of the zones to produce estimates of the annual volume of ground water discharged. The discharge estimated for Dixie Valley is between 17,000 and 28,000 acre-feet per year. The revised discharge estimate for the entire Dixie Valley area is between 20,000 and 31,000 acre-feet per year. The revised ground-water budget for the entire Dixie Valley study area has a total recharge of about 23,000 acre-feet per year. This is within the range of estimates of natural discharge--from 20,000 to 31,000 acre-feet per year. For Dixie Valley alone, the total recharge of about 8,900 acre-feet per year and the estimated subsurface inflow from tributary areas of about 11,000 acre-feet per year produce an estimated total inflow of about 20,000 acre-feet per year. This compares with the discharge estimate of 17,000 to 28,000 acre-feet per year.

Water-Resources Investigations Report↗
USGS1986

Water resources data, Florida, water year 1986. Volume 3B. Southwest Florida-ground water

Water resources data for the 1986 water year in Florida consist of continuous or daily discharge for 277 streams, periodic discharge for 38 streams, miscellaneous discharge for 34 streams, continuous or daily stage for 77 streams, periodic stage for 20 streams, peak discharge for 88 streams and peak stage for 69 streams; continuous or daily elevations for 69 lakes, periodic elevations for 72 lakes; continuous ground-water levels for 476 wells, periodic ground-water levels for 1226 wells, and miscellaneous water-level measurements for 1570 wells; quality-of-water data for 188 surface-water sites and 878 wells. The data for southwest Florida include continuous or daily discharge for 85 streams, periodic discharge for 21 streams, miscellaneous discharge for 7 streams, continuous or daily stage for 26 streams, periodic stage for 10 streams, peak discharge for 20 streams, and peak stage for 1 stream; continuous elevations for 30 lakes and periodic elevations for 28 lakes; continuous ground-water levels for 25 wells, periodic ground-water levels for 146 wells, and miscellaneous water-level measurements for 722 wells; quality-of-water for 106 surface-water sites and 265 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.

Florida↗
USGS1995

Water resources data, Florida, water year 1994. Volume 2B: South Florida - ground water

Water resources data for 1994 water year in Florida consists of continuous or daily discharge for 320 streams, periodic discharge for 11 streams, miscellaneous discharge for 32 streams, continuous or daily stage for 120 streams, continuous daily tide stage for 11 sites, periodic stage for 0 streams, peak discharge for 19 streams, and peak stage for 19 streams; continuous or daily elevations for 74 lakes, periodic elevations for 74 lakes; continuous ground-water levels for 442 wells, periodic ground-water levels for 716 wells, and miscellaneous water level measurements for 1,208 wells; quality of water data for 121 surface-water sites and 319 wells. The data for South Florida included continuous or daily discharge for 74 streams, continuous or daily stage for 59 streams, peak stage discharge for no streams, continuous elevation for 1 lake; continuous groundwater levels for 224 wells, periodic ground-water levels for 437 wells and no miscellaneous water-level measurements; quality-of-water for 9 surface-water sites and 247 wells. The data represent the National Water Data System records collected by the U.S. Geological Survey and cooperation with local, state, and federal agencies in Florida.

Florida↗
USGS2009

Validation of a Ground-Water Flow Model of the Mississippi River Valley Alluvial Aquifer Using Water-Level and Water-Use Data for 1998-2005 and Evaluation of Water-Use Scenarios

A ground-water flow model of the Mississippi River Valley alluvial aquifer in eastern Arkansas, developed in 2003 to simulate the period of 1918-98, was validated with the addition of water-level and water-use data that extended the observation period to 2005. The original model (2003) was calibrated using water-level observations from 1972, 1982, 1992, and 1998, and water-use data through 1997. The original model subsequently was used to simulate water levels from 1999 to 2049 and showed that simulation of continued pumping at the 1997 water-use rate could not be sustained indefinitely without causing dry cells in the model. After publication of the original ground-water flow model, a total of 3,616 water-level observations from 698 locations measured during the period of 1998 to 2005 became available. Additionally, water-use data were compiled and used for the same period, totaling 290,005 discrete water-use values from 43,440 wells with as many as 39,169 wells pumping in any one year. Total pumping (which is primarily agricultural) for this 8-year period was about 2.3 trillion cubic feet of water and was distributed over approximately 10,340 square miles within the model area. An updated version of the original ground-water flow model was used to simulate the period of 1998-2005 with the additional water-level and water-use data. Water-level observations for 1998-2005 ranged from 74 to 293 feet above National Geodetic Vertical Datum of 1929 across the model area. The maximum water-level residual (observed minus simulated water-level values) for the 3,616 water-level observations was 52 feet, the minimum water-level residual was 60 feet, the average annual root mean squared error was 8.2 feet, and the annual average absolute residual was 6.0 feet. A correlation coefficient value of 0.96 was calculated for the line of best fit for observed to simulated water levels for the combined 1998-2005 dataset, indicating a good fit to the data and an acceptable validation of the model. After the validation process was completed, additional ground-water model simulations were run to evaluate the response of the aquifer with the 2005 water-use rate applied through 2049 (scenario 1) and the 2005 water-use rate increased 2 percent annually until 2049 (scenario 2). Scenario 1 resulted in 779 dry cells (779 square miles) by 2049 and scenario 2 resulted in 2,910 dry cells (2,910 square miles) by 2049. In both scenarios, the dry cells are concentrated in the Grand Prairie area and Cache River area west of Crowleys Ridge. However, scenario 2 resulted in dry cells to the east of Crowleys Ridge as well. A simulation applying the 1997 water-use rate contained in the original ground-water flow model resulted in 401 dry cells (401 square miles) in the Grand Prairie and Cache River areas.

Scientific Investigations Report↗
USGS2003

Water resources data Texas, water year 2003, volume 6. Ground water

Water-resources data for the 2003 water year for Texas consists of records of stage, discharge, and water quality of streams; stage and contents in lakes and reservoirs; and water levels and water quality in wells. Volume 6 contains water levels for 880 ground-water observation wells and water-quality data for 158 monitoring wells. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating Federal, State, and local agencies in Texas.

Texas↗
USGS2008

Source, Distribution, and Management of Arsenic in Water from Wells, Eastern San Joaquin Ground-Water Subbasin, California

Between 1974 and 2001 water from as many as one-third of wells in the Eastern San Joaquin Ground Water Subbasin, about 80 miles east of San Francisco, had arsenic concentrations greater than the U.S. Environmental Protection Agency Maximum Contaminant Level (MCL) for arsenic of 10 micrograms per liter (ug/L). Water from some wells had arsenic concentrations greater than 60 ug/L. The sources of arsenic in the study area include (1) weathering of arsenic bearing minerals, (2) desorption of arsenic associated with iron and manganese oxide coatings on the surfaces of mineral grains at pH's greater than 7.6, and (3) release of arsenic through reductive dissolution of iron and manganese oxide coatings in the absence of oxygen. Reductive dissolution is responsible for arsenic concentrations greater than the MCL. The distribution of arsenic varied areally and with depth. Concentrations were lower near ground-water recharge areas along the foothills of the Sierra Nevada; whereas, concentrations were higher in deeper wells at the downgradient end of long flow paths near the margin of the San Joaquin Delta (fig. 1). Management opportunities to control high arsenic concentrations are present because water from the surface discharge of wells is a mixture of water from the different depths penetrated by wells. On the basis of well-bore flow and depth-dependent water-quality data collected as part of this study, the screened interval of a public-supply well having arsenic concentrations that occasionally exceed the MCL was modified to reduce arsenic concentrations in the surface discharge of the well. Arsenic concentrations from the modified well were about 7 ug/L. Simulations of ground-water flow to the well showed that although upward movement of high-arsenic water from depth within the aquifer occurred, arsenic concentrations from the well are expected to remain below the MCL.

Open-File Report↗
USGS2008

Methods and sources of data used to develop selected water-quality indicators for streams and ground water for EPA's 2007 Report on the Environment: Science report

The U.S. Geological Survey (USGS) was one of numerous governmental agencies, private organizations, and the academic community that provided data and interpretations for the U.S. Environmental Protection Agency’s (USEPA) 2007 Report on the Environment: Science Report . This report documents the sources of data and methods used to develop selected water–quality indicators for the 2007 edition of the report compiled by USEPA. Stream and ground–water–quality data collected nationally in a consistent manner as part of the USGS’s National Water–Quality Assessment Program (NAWQA) were provided for several water–quality indicators, including Nitrogen and Phosphorus in Streams in Agricultural Watersheds; Pesticides in Streams in Agricultural Watersheds; and Nitrate and Pesticides in Shallow Ground Water in Agricultural Watersheds . In addition, the USGS provided nitrate (nitrate plus nitrite) and phosphorus riverine load estimates calculated from water–quality and streamflow data collected as part of its National Stream Water Quality Accounting Network (NASQAN) and its Federal–State Cooperative Program for the Nitrogen and Phosphorus Discharge from Large Rivers indicator.

Open-File Report↗
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↗
USGS1988

U.S. Geological Survey ground-water studies in Texas

Ground-water resources supply almost 60 percent of the freshwater used in Texas, excluding withdrawals for thermoelectric-power generation (less than 3 percent). About 73 percent of the ground water withdrawn is used for irrigation, about 17 percent for public supply, and about 7 percent for industrial, rural domestic, and livestock uses. About 8 million people, or 48 percent of the population of Texas, depend on ground water as a public or rural domestic supply. The dependence on ground water is greatest in the arid northwestern part of the State, where most of the water is used for irrigation. This area contains 70 percent of all irrigated land in Texas, and uses about 85 percent of the total ground water withdrawn for irrigation.

Texas↗
USGS1980

Sulfate reduction in ground water of southeastern Montana

Ground water in southeastern Montana was investigated to determine if sulfide production was bacterially mediated. Sulfate—reducing bacteria were detected in 25 of 26 ground—water samples in numbers ranging from 2.0 x 10 1 to greater than 2.4 x 10 4 bacteria per 100 milliliters. Stable sulfur isotope fractionation studies indicate a biological role in sulfate reduction. However, sulfate—reducing activity as determined by use of a radioactive sulfur isotope was observed in only 1 of 16 samples. Bacterial dissimilatory sulfate reduction is postulated to be responsible for a major part of the sulfide produced in these ground waters. These bacteria are most likely active in the adsorbed state, possibly in subsurface microzones where environmental conditions are conducive to sulfate reduction.

Montana↗
USGS1988

Ground-water flow and quality beneath sewage-sludge lagoons, and a comparison with the ground-water quality beneath a sludge-amended landfill, Marion County, Indiana

The groundwater beneath eight sewage sludge lagoons, was studied to characterize the flow regime and to determine whether leachate had infiltrated into the glacio-fluvial sediments. Groundwater quality beneath the lagoons was compared with the groundwater quality beneath a landfill where sludge had been applied. The lagoons and landfills overlie outwash sand and gravel deposits separated by discontinuous clay layers. Shallow groundwater flows away from the lagoons and discharges into the White River. Deep groundwater discharges to the White River and flows southwest beneath Eagle Creek. After an accumulation of at least 2 inches of precipitation during 1 week, groundwater flow is temporarily reversed in the shallow aquifer, and all deep flow is along a relatively steep hydraulic gradient to the southwest. The groundwater is predominantly a calcium bicarbonate type, although ammonium accounts for more than 30% of the total cations in water from three wells. Concentrations of sodium, chloride, sulfate, iron, arsenic, boron, chemical oxygen demand, total dissolved solids, and methylene-blue-active substances indicate the presence of leachate in the groundwater. Concentrations of cadmium, chromium, copper, lead, mercury, nickel, selenium, and zinc were less than detection limits. The concentrations of 16 of 19 constituents or properties of groundwater beneath the lagoons are statistically different than groundwater beneath the landfill at the 0.05 level of significance. Only pH and concentrations of dissolved oxygen and bromide are higher in groundwater beneath the landfill than beneath the lagoons.

Indiana↗
USGS1995

Ground-water quality protection: Why it's important to you

Ground water is a valuable resource often used for industry, commerce, agriculture, and drinking water. In the 19080's, ground water provided 35 percent of the municipal water supplies in the United States and 95 percent of the rural, domestic drinking water. Scientists participating in ground-water studies may determine the potential pathways that contaminants could be transported in aquifers. In karst terrain especially, a contanimant can enter a fracture network in a carbonate aquifer and quickly spread to become a widespread health problem. Although Federal and local funding for ground-water cleanups and treatment may be available, the costs can exceed many millions of dollars each year. Such costly remedial actions could be avoided or minimized by becoming aware that ground water anywhere is vulnerable to contamination, but particularly so in carbonate terrain. Practicing good "out-of-doors" house- keeping is necessary. From the standpoint of economic and environmental responsibility, it is critical that we all work together to protect the quality of ground-water resources so that future generations can continue to have clean water.

Tennessee↗