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At least 937 records · Page 52Linked to original sources
USGS1964

Ground-water provinces of southern Rhodesia

Ground-water development, utilization, and occurrence in nine ground-water provinces of Southern Rhodesia are summarized in this report. Water obtained from drilled wells for domestic and stock use has played an important part in the social and economic development of Southern Rhodesia from the beginnings of European settlement to the present. Most of the wells obtain water from fractures and weathered zones in crystalline rocks, before recently, there has been an interest in the possibility of obtaining water for irrigation from wells. Studies of the authors indicate that quantities of water sufficient for irrigation can be obtained from alluvial sediments in the S'abi Valley, from Kalahari sands in the western part of the country, are perhaps from aquifers in other areas. The ground-water provinces fall into two groups--those in the crystalline rocks and those in the noncrystalline rocks. Historically, the wells in crystalline rocks, especially the Gold belts province and the Intrusive granites province, have played a major role in supplying water for the needs of man. These provinces, together with two other less important crystalline rock provinces, form the broad arch which constitutes the central core of the country. The noncrystalline rocks overlie and flank the crystalline rocks to the southeast, northwest, and north. The noncrystalline rock provinces, especially the Alluvium-Kalahari province, contain the most productive or potentially productive ground-water reservoirs in Southern Rhodesia and offer promise of supplying water for irrigation and for other purposes.

Water Supply Paper↗
USGS1964

Selected hydrologic data, upper Sevier River basin, Utah

This report is intended to serve two purposes: (1) to make available to the public basic ground-water data useful in planning and studying development of water resources, and (2) to supplement an interpretive report that will be published later. Records were collected during 1961-63 by the U.S. Geological Survey in cooperation with the Utah State Engineer as a part of the investigation of ground-water conditions in the upper Sevier River basin, in parts of Garfield, Iron, Kane, Piute, and Sevier Counties, Utah. The interpretive material will be published in a companion report by Carl H. Carpenter, Gerald B. Robinson, Jr., and Louis J. Bjorklund. This report is most useful in predicting conditions likely to be found in areas that are being considered as well sites. The person considering the new well can spot the proposed site on plate 1 and examine the records of nearby wells and springs as shown in the tables. From table 1 he can find information on wells, including depth, diameter, water level, yield, drawdown, use of water, temperature of water, and depth of perforations. Table 2 gives information on springs such as yield, use of water, temperature, and improvements. From tables 1 and 2 he can note the type of material that yields water in the vicinity. Table 3 shows the historic fluctuations and trends of water levels. Table 4 shows the type of material penetrated by wells. From table 5 he can note the chemical quality of water from wells and springs, and from table 6, the chemical quality of surface water. If the reader decides from his examination that conditions are favorable, he can place an application to drill a well with the State Engineer. If the State Engineer believes unappropriated water is available, the application may be approved after minimum statutory requirements have been satisfied. The report is also useful when planning large-scale developments of water supply. This and other uses of the report will be helped by use of the interpretive report upon its release.

Utah↗
USGS2001

Ground-water flow to Death Valley, as inferred from the chemistry and geohydrology of selected springs in Death Valley National Park, California and Nevada

Death Valley lies downgradient from adjacent valleys to the north, south, east, and west in California and Nevada, and is the site of substantial ground-water discharge. The sources of the discharging waters have been discussed by several investigators in the past and are of heightened concern because of the potential disposal of high-level radioactive waste at Yucca Mountain, Nevada, and because of ground-water withdrawals attendant to commercial mining in the northwestern Amargosa Valley region. This report describes high- and low-discharge springs in and along the Amargosa Range that were sampled to augment the level of understanding of the extent and distribution of westward ground-water flow through the range. The Black Mountains do not seem to be part of a significant path of ground-water flow from the Amargosa region. This is attributed to the complex lithology and geologic history of the Black Mountains structural block and to the presence of the intervening Furnace Creek fault zone. The only ground-water discharge associated with the Black Mountains where water chemistry reflects an external source or sources is Saratoga Spring, for which δ 2 H and δ 18 O data indicate recharge in the Spring Mountains to the east. The southern part of the Funeral Mountains transmits a large volume of water through faulted and fractured rocks of Cambrian age that lie at or along the distal part of the northeast -oriented Spotted Range-Mine Mountain structural zone. Waters discharging from springs in the Furnace Creek Ranch vicinity (Travertine and Nevares) both compositionally and isotopically resemble waters from the Ash Meadows spring group in the Amargosa Desert. The Ash Meadows springs and water in the Amargosa Valley alluvium likely are chemically representative of ground water entering the southern Funeral Mountains. Much less ground water flows through the central and northern Funeral Mountains than flows through the southern part, as indicated by the geologic setting and chemistry of Keane Wonder Spring. The northern one-half of the mountains comprises early-to-middle Proterozoic metamorphic rocks that are the core of the Funeral Mountains anticlinorium. The core is largely unfaulted, plunges to the northeast and southwest, and is truncated to some extent on the east by the shallow-dipping Boundary Canyon fault. This structural setting and the paucity of springs in the northern one-half of the Funeral Mountains indicate a long traveltime from the Amargosa region to the western margin of the northern and central parts of the mountains. The Grapevine Mountains include the highest elevations in the Amargosa Range. Substantial precipitation and recharge above about 2,000 meters are evinced by numerous small springs and seeps along the east and west margins. The local nature of the recharge is reflected in δ 2 H and δ 18 O values and in the spring chemistries that indicate control by Tertiary volcanic rocks. The highest spring discharges associated with the Grapevine Mountains are near the north end of the mountains in the Grapevine Ranch area. The springs in this area are similar chemically and isotopically, except for one or two order-of-magnitude differences in calcium, magnesium, and strontium concentrations and a 1.2 per mil difference in δ 13 C values. These differences can be attributed to differences in the distal parts of the respective flow paths. The springs also lie at the end of a northeast -oriented structural zone in the Walker Lane Belt, and their δ 2 H, δ 13 C, and δ 18 O values indicate a recharge area likely to the northeast, outside of the Grapevine Mountains.

California;Nevada↗
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↗
USGS1994

Potential effects of the Hawaii Geothermal Project on ground-water resources on the island of Hawaii

In 1990, the State of Hawaii proposed the Hawaii Geothermal Project for the development of as much as 500 MW of electric power from the geothermal system in the East Rift Zone of Kilauea Volcano. This report uses data from 31 wells and 8 springs to describe the properties of the ground-water system in and adjacent to the East Rift Zone. Potential effects of this project on ground-water resources are also discussed. Data show differences in ground-water chemistry and heads within the study area that appear to be related to mixing of waters of different origins and ground-water impoundment by volcanic dikes. East of Pahoa, the ground-water system within the rift is highly transmissive and receives abundant recharge from precipitation; therefore, the pumping of freshwater to support geothermal development in that part of the rift zone would have a minimal effect on ground-water levels. To the southwest of Pahoa, dike impoundment reduces the transmissivity of the ground-water system to such an extent that wells might not be capable of supplying sufficient fresh water to support geothermal operations. Contamination of ground-water resources by accidental release of geothermal fluids into shallow aquifers is possible because of corrosive conditions in the geothermal wells, potential well blowouts, and high ground-water velocities in parts of the region. Hydrologic monitoring of water level, temperature, and chemistry in observation wells should continue throughout development of geothermal resources for the Hawaii Geothermal Project for early detection of leakage and migration of geothermal fluids within the groundwater system.

Water-Resources Investigations Report↗
USGS1997

Radon in ground water in Guilford County, North Carolina

Approximately 30 percent of the water used in Guilford County, North Carolina, is from ground-water sources. All rural supplies are from ground water; approximately 65,000 residents used ground water for their domestic water supplies in 1990. The U.S. Geological Survey (USGS), in cooperation with the Guilford County Soil and Water Conservation District and the Guilford County Department of Health, began a study in 1996 of the hydrogeology of Guilford County to update previous work. As part of this effort and according to methods presented in Koterba and others (1995), dissolved radon samples were collected from 70 wells throughout the county. Because radon in ground water poses a potential health hazard, this report presents results from this sampling effort and the implications that radon may have on ground-water use in Guilford County.

North Carolina↗
USGS1995

Water-resources data for the Fort Berthold Indian Reservation, west-central North Dakota

A study of the water resources of the Fort Berthold Indian Reservation was undertaken to characterize the quality and quantity of ground-water and surface-water resources. The purpose of this report is to document the data-collection procedures used during the study and to present the data collected in tabular and graphical form. Ground-water data were collected during May 1990 through November 1992. The data presented in this report include records of 1,325 wells, test holes, and springs; water-levels fcr 40 observation wells; drillers' logs for 211 wells and test holes; gamma-ray and resistivity logs for 21 test holes drilled in June 1992; water-quality data for 293 water samples from wells ani springs; and trace-element data for 225 water samples from wells. Surface-water data were collected on Bear Den Creek, East Fork Shell Creek, Deepwater Creek, Moccasin Creek, and Squaw Creek from April 1990 through September 1992. Initial!}', five miscellaneous measurement sites were established so that discharge data, selected physical properties of water, and water samples for water-quality analysis could be collected. Gravity data were collected over parts of the Fort Berthold Indian Reservation. As part of the gravity survey, positional data were acquired using global positioning satellite technology.

Open-File Report↗
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↗
USGS2007

MODFLOW-2005, The U.S. Geological Survey Modular Ground-Water Model - Documentation of the Multiple-Refined-Areas Capability of Local Grid Refinement (LGR) and the Boundary Flow and Head (BFH) Package

This report documents the addition of the multiple-refined-areas capability to shared node Local Grid Refinement (LGR) and Boundary Flow and Head (BFH) Package of MODFLOW-2005, the U.S. Geological Survey modular, three-dimensional, finite-difference ground-water flow model. LGR now provides the capability to simulate ground-water flow by using one or more block-shaped, higher resolution local grids (child model) within a coarser grid (parent model). LGR accomplishes this by iteratively coupling separate MODFLOW-2005 models such that heads and fluxes are balanced across the shared interfacing boundaries. The ability to have multiple, nonoverlapping areas of refinement is important in situations where there is more than one area of concern within a regional model. In this circumstance, LGR can be used to simulate these distinct areas with higher resolution grids. LGR can be used in two-and three-dimensional, steady-state and transient simulations and for simulations of confined and unconfined ground-water systems. The BFH Package can be used to simulate these situations by using either the parent or child models independently.

Techniques and Methods↗
USGS2002

Louisiana Ground-Water Map No.13: Hydrogeology and Potentiometric Surface of the Sparta Aquifer in Northern Louisiana, October 1996

This report describes the thickness and areal extent of the Sparta aquifer, identifies sands within the fresh-water extent of the aquifer, and presents data and a map that illustrate the generalized potentiometric surface (water levels) during October 1996. The report includes a detailed geophysical log, structure contour maps, hydrogeologic sections, and hydrographs of water levels in selected wells. The potentiometric surface-map can be used for determining direction of ground-water flow, hydraulic gradients, and the effects of withdrawals on the aquifer.

Water-Resources Investigations Report↗
USGS1988

Ground-water resources of the central Wasatch Front area, Utah

This is one of a series of map reports compiled by the USGS and UGS describing the geology and related natural resources and hazards of the densely populated Wasatch Front of Utah. This report defines in a non-technical format the occurrence, availability, and quality of ground water in the central Wasatch Front area and guides readers to sources of more detailed information about the resource.

Utah↗
USGS1988

Ground-water resources of the southern Wasatch Front area, Utah

This is one of a series of map reports compiled by the USGS and UGS describing the geology and related natural resources and hazards of the densely populated Wasatch Front of Utah. This report defines in a non-technical format the occurrence, availability, and quality of ground water in the southern Wasatch Front area and guides readers to sources of more detailed information about the resource.

Utah↗
USGS1998

Nitrate and pesticides in ground water in the eastern San Joaquin Valley, California : Occurrence and trends

The occurrence of nitrate and pesticides in ground water in California's eastern San Joaquin Valley may be greatly influenced by the long history of intensive farming and irrigation and the generally permeable sediments. This study, which is part of the U.S. Geological Survey National Water-Quality Assessment Program, was done to assess the quality of the ground water and to do a preliminary evaluation of the temporal trends in nitrate and pesticides in the alluvial fans of the eastern San Joaquin Valley. Ground-water samples were collected from 30 domestic wells in 1995 (each well was sampled once during 1995). The results of the analyses of these samples were related to various physical and chemical factors in an attempt to understand the processes that control the occurrence and the concentrations of nitrate and pesticides. A preliminary evaluation of the temporal trends in the occurrence and the concentration of nitrate and pesticides was done by comparing the results of the analyses of the 1995 ground-water samples with the results of the analyses of the samples collected in 1986-87 as part of the U.S. Geological Survey Regional Aquifer-System Analysis Program. Nitrate concentrations (dissolved nitrate plus nitrite, as nitrogen) in ground water sampled in 1995 ranged from less than 0.05 to 34 milligrams per liter, with a median concentration of 4.6 milligrams per liter. Nitrate concentrations exceeded the maximum contaminant level of 10 milligrams per liter (as nitrogen) in 5 of the 30 ground-water samples (17 percent), whereas 12 of the 30 samples (40 percent) had nitrate concentrations less than 3.0 milligrams per liter. The high nitrate concentrations were associated with recently recharged, well-oxygenated ground water that has been affected by agriculture (indicated by the positive correlations between nitrate, dissolved-oxygen, tritium, and specific conductance). Twelve pesticides were detected in 21 of the 30 ground-water samples (70 percent) in 1995, although only 5 pesticides were detected in more than 10 percent of the ground-water samples. All 12 pesticides were detected at concentrations below the maximum contaminant levels, except the banned soil fumigants 1,2-dibromo-3-chloropropane (3 detections) and 1,2-dibromoethane (1 detection). Atrazine and desethyl atrazine (a transformation product of atrazine) were the most frequently detected pesticides; they were detected in 11 ground-water samples. The frequent detections of atrazine and desethyl atrazine may be related either to past applications of atrazine or to recent application on rights-of-way. Simazine was detected in 10 ground-water samples and diuron was detected in 4 ground-water samples. The detections of simazine and diuron are generally consistent with their reported applications on the crops near the wells where they were detected. 1,2,3-trichloropropane, a manufacturing by-product of 1,2-dichloropropane and 1,3- dichloropropene formulations, was detected in 4 ground-water samples. The occurrence of 1,2,3-trichloropropane, 1,2-dibromo-3-chloropropane, and 1,2-dibromoethane is probably related to past use. Similar to nitrate concentrations, pesticide occurrence was positively correlated to dissolved-oxygen concentrations, indicating that areas with high dissolved-oxygen concentrations may be vulnerable to contamination by nitrate and pesticides. High dissolved-oxygen concentrations may be associated with water that has been rapidly recharged. A comparison of the concentrations and the occurrence of nitrate and pesticides between 1986-87 and 1995 indicates that nitrate concentrations may pose a greater threat to the quality of the ground-water resource in this region than pesticides, in the context of current drinking-water standards. Nitrate concentrations were significantly higher in the 1995 ground-water samples than in the 1986-87 samples collected from the same wells.

Calfornia↗
USGS2000

Assessment of potential for natural attenuation of chlorinated ethenes and ethanes in ground water at a petrochemical reclamation site, Harris County, Texas

Redox conditions in the Numerous Sand Channels Zone beneath a petrochemical reclamation site in Harris County, Texas, range from sulfate reducing to methanogenic as indicated by the presence of methane in ground water and the range of molecular hydrogen concentrations. Assessment of the potential for reductive dechlorination using BIOCHLOR as a screening tool indicated conditions favoring anaerobic degradation of chlorinated organic compounds in the Numerous Sand Channels Zone. Evidence supporting reductive dechlorination includes apparently biogenic cis -1,2-dichloroethene; an increased ratio of 1,2-dichloroethane to 1,1,2-trichloroethane downgradient from the assumed contaminant source area; ethene and methane concentrations greater than background concentrations within the area of the contaminant plume; and a positive correlation of the ratio of ethene to vinyl chloride as a function of methane concentrations. The body of evidence presented in this report argues for hydrogenolysis of trichloroethene to cis -1,2-dichloroethene; of 1,1,2-trichloroethane to 1,2-dichloroethane; and of vinyl chloride to ethene within the Numerous Sand Channels Zone. Simulations using BIOCHLOR yielded apparent first-order decay constants for reductive dechlorination in the sequence tetrachloroethene trichloroethene cis -1,2-dichloroethene vinyl chloride ethene within the range of literature values reported for each compound and apparent first-order decay constants for reductive dechlorination in the sequence 1,1,2-trichloroethane 1,2-dichloroethane slightly greater than literature values reported for each compound along the upgradient segment of a simulated ground-water flowpath. Except for vinyl chloride, apparent rates of reductive dechlorination for all simulated species show a marked decrease along the downgradient segment of the simulated ground-water flowpath. Evidence for reductive dechlorination of chlorinated ethenes within the Numerous Sand Channels Zone indicates potential for natural attenuation of chlorinated ethenes. Reductive dechlorination of chlorinated ethanes apparently occurs to a lesser extent, indicating relatively less potential for natural attenuation of chlorinated ethanes. Additional data are needed on the concentrations and distribution of chlorinated ethenes and ethanes in individual fine sand intervals of the Numerous Sand Channels Zone. This information, combined with lower minimum reporting levels for future chloroethane analyses, might enable a more complete and quantitative assessment of the potential for natural attenuation at the site.

Texas↗