SEARCH · USGS Science
Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Some of the basic material contained in this report originally was prepared in 1952 as instructional handouts for ground-water short courses and for training of foreign participants. The material has been revised and expanded and is presented in the present form to make it more readily available to the field hydrologist. Illustrations now present published examples of the applications suggested in the 1952 material. For small areas, a field pumping test is sufficient to predict the characteristics of an aquifer. With a large area under study, the aquifer properties must be determined at many different locations and it is not usually economically feasible to make sufficient field tests to define the aquifer properties in detail for the whole aquifer. By supplementing a few field tests with laboratory permeability data and geologic interpretation, more point measurements representative of the hydrologic properties of the aquifer may be obtained. A sufficient number of samples seldom can be obtained to completely identify the permeability or transmissibility in detail for a project area. However, a few judiciously chosen samples of high quality, combined with good geologic interpretation, often will permit the extrapolation of permeability information over a large area with a fair degree of reliability. The importance of adequate geologic information, as well as the importance of collecting samples representative of at least all major textural units lying within the section or area of study, cannot be overemphasized.
The Wasatch Plateau-Book Cliffs%area as used in this report consists of about 8,000 square miles in east-central Utah. The major geographic features included in the area are the Wasatch Plateau, Book Cliffs, San Rafael Swell, Price River basin, and a small part of the Green River basin (pl. 1). The area is defined by approximate drainage-divide boundaries in the Wasatch Plateau and Book Cliffs, by an arbitrary boundary on the south, and by the Utah-Colorado State line on the east. The Wasatch Plateau-Book Cliffs area includes all the operating coal mines in Utah in 1978. Annual coal production in the area is expected to increase from the current (1978) rate of about 8 million tons to as much as 30 million tons within the next 10 years (J. W. Moffitt, U.S. Geological Survey, oral commun., 1978). Ground water is an important source of water supply in the area. As mining increases and mining-related municipalities grow, many sources of ground-water supply may be subjected to increased demands and possibly degradation of chemical quality. Waddell, Vickers, Upton, and Contratto (1978) reported some ground- water data after a reconnaissance of part of the area. The purpose of this report, which was prepared in cooperation with the U.S. Bureau of Land Management, is to present a more detailed compilation of ground-water-related data that were collected and compiled during October 1976 to March 1978. The report is designed to make the data available in an orderly and usable form for local and regional water managers and other users of water data.
This report was prepared in cooperation with several organizations in the Salt Lake Valley and with the Central Utah Water Conservancy District to present results of a study to determine changes in the ground-water conditions in Salt Lake Valley, Utah, from 1969 to 1983, and to predict the aquifer response to projected withdrawals. The average annual recharge and discharge from the ground-water reservoir in Salt Lake Valley, Utah, during 1969-82 were estimated to be about 352,000 and 353,000 acre-feet per year. Withdrawals from wells increased from 107,000 acre-feet per year during 1964-68 to 117,000 acre-feet per year during 1969-82. The greatest increase in use was for public supply and institutions which increased from 35,000 acre-feet per year during 1964-68 to 46,700 acre-feet per year during 1969-82.
The potential effects of water-management plans on stream-aquifer systems in several countries have been simulated using electric-analog or digital-computer models. Many of the electric-analog models require large amounts of hardware preparation for each problem to be solved and some become so bulky that they present serious space and access problems. Digital-computer models require no special hardware preparation but often they require so many repetitive solutions of equations that they result in calculations that are unduly unwieldy and expensive, even on the latest generation of computers. Further, the more detailed digital models require a vast amount of core storage, leaving insufficient storage for evaluation of the many possible schemes of water-management. A concept introduced in 1968 by the senior author of this report offers a solution to these problems. The concept is that the effects on streamflow of ground-water withdrawal or recharge (stress) at any point in such a system can be approximated using two classical equations and a value of time that reflects the integrated effect of the following: irregular impermeable boundaries; stream meanders; aquifer properties and their areal variations; distance of the point from the stream; and imperfect hydraulic connection between the stream and the aquifer. The value of time is called the stream depletion factor ( sdf ). Results of a relatively few tests on detailed models can be summarized on maps showing lines through points of equal sdf . Sensitivity analyses of models of two large stream-aquifer systems in the State of Colorado show that the sdf technique described in this report provides results within tolerable ranges of error. The sdf technique is extremely versatile, allowing water managers to choose the degree of detail that best suits their needs and available computational hardware. Simple arithmetic, using, for example, only a slide rule and charts or tables of dimensionless values, will be sufficient for many calculations. If a large digital computer is available, detailed description of the system and its stresses will require only a fraction of the core storage, leaving the greater part of the storage available for sophisticated analyses, such as optimization. Once these analyses have been made, the model then is ready to perform its principal task--prediction of streamflow and changes in ground-water storage. In the two systems described in this report, direct diversion from the streams is the principal source of irrigation water, but it is supplemented by numerous wells. The streamflow depends largely on snowmelt. Estimates of both the amount and timing of runoff from snowmelt during the irrigation season are available on a monthly basis during the spring and early summer. These estimates become increasingly accurate as the season progresses, hence frequent changes of stress on the predictive model are necessary. The sdf technique is especially well suited to this purpose, because it is very easy to make such changes, resulting in more up-todate estimates of the availability of streamflow and ground-water storage. These estimates can be made for any time and any location in the system.
A computer simulation of Long Island 's regional groundwater system has been used to evaluate the effects that new-installed sewers will have on ground-water levels. Results indicate maximum water-table decliners of as much as up to 18 feet in central Nassau County and about 9 feet in Suffolk County. Total stream base flows and freshwater outflow to the south shore bay system will decrease by 22%. The regional scale of the model does not permit detailed predictions for individual streams. To quantify the effects of lowered ground-water levels on individual streams, two fine-scale sub-regional models have been designed. This report, the first in a three-part series describing the simulated effects of sewers in southern Nassau and southwestern Suffolk Counties, presents the hydrogeologic setting, pertinent literature, modeling strategy, subregional model design, and the results obtained to date from the regional ground-water model. The regional model results described will be used in the later reports to generate flux boundary conditions for the subregional models.
Sulfonylurea (SU), sulfonamide (SA), and imidazolinone (IMI) herbicides are recently developed herbicides that function by inhibiting the action of a key plant enzyme, stopping plant growth, and eventually killing the plant. These compounds generally have low mammalian toxicity, but crop and non-crop plants demonstrate a wide range in sensitivity to SUs, SAs, and IMIs, with over a 10,000-fold difference in observed toxicity levels for some compounds. SUs, SAs, and IMIs are applied either pre- or post-emergence to crops commonly at 1/50th or less of the rate of other herbicides. Little is known about their occurrence, fate, or transport in surface water or ground water in the United States. To obtain information on the occurrence of SU, SA, and IMI herbicides in the Midwestern United States, 214 water samples were collected from 76 surface-water and 25 ground-water sites in 1998. These samples were analyzed for 16 SU, SA, and IMI herbicides by using highperformance liquid chromatography/mass spectrometry. Samples also were analyzed for 46 pesticides and pesticide degradation products and 13 herbicides and 10 herbicide degradates. At least 1 of the 16 SUs, SAs, or IMIs was detected at or above the method reporting limit of 0.010 microgram per liter (ug/L) in 83 percent of 133 stream samples. Imazethapyr was detected most frequently (69 percent of samples), followed by flumetsulam (65 percent of samples) and nicosulfuron (53 percent of samples). At least one SU, SA, or IMI herbicide was detected at or above the method reporting limit in 6 of 8 reservoir samples and 5 of 25 ground-water samples. SU, SA, and IMI herbicides occurred less frequently and at a fraction (often 1/50th or less) of the concentrations of other herbicides such as atrazine. Acetochlor, atrazine, cyanazine, and metolachlor were all detected in 95 percent or more of 136 stream samples.
This report was prepared in cooperation with several organizations in the Salt Lake Valley and with the Central Utah Water Conservancy District to present results of a study to determine changes in the ground-water conditions in Salt Lake Valley, Utah, from 1969 to 1983, and to predict the aquifer response to projected withdrawals. The average annual recharge and discharge from the ground-water reservoir in Salt Lake Valley, Utah, during 1969-82 were estimated to be about 352,000 and 353,000 acre-feet per year. Withdrawals from wells increased from 107,000 acre-feet per year during 1964-68 to 117,000 acre-feet per year during 1969-82. The greatest increase in use was for public supply and institutions which increased from 35,000 acre-feet per year during 1964-68 to 46,700 acre-feet per year during 1969-82. From 1969 to 1983 water levels declined from 5 to 15 feet in the southeast part of the valley where pumpage from large public supply wells was greater during 1969-82 than during previous years. From February-March 1969 to February-March 1983 the quantity of ground water in storage in Salt Lake Valley increased by about 33,000 acre-feet. A digital-computer model was calibrated to simulate, in three-dimensions, the ground-water flow in the principal and shallow-unconfined aquifers in Salt Lake Valley. Simulations were made to project the response to continuing withdrawals through 2020. Alternative pumping rates used were (1) the 1982 rate of pumpage and (2) increasing the 1982 rate of pumpage by 65,000 acre-feet. The simulation at the increased rate of pumpage indicated that drawdowns would reach 40-60 feet in the area east of Sandy. About 75 percent of the increased withdrawal was salvaged from water that otherwise would have been discharged to the Jordan River and its tributaries.
This report documents the development of a computer model to simulate steady-state (long-term average) flow of ground water in the vicinity of Mirror Lake, which lies at the eastern end of the Hubbard Brook valley in central New Hampshire. The 10-km2 study area includes Mirror Lake, the three streams that flow into Mirror Lake, Leeman's Brook, Paradise Brook, and parts of Hubbard Brook and the Pemigewasset River. The topography of the area is characterized by steep hillsides and relatively flat valleys. Major hydrogeologic units include glacial deposits, composed of till containing pockets of sand and gravel, and fractured crystalline bedrock, composed of schist intruded by granite, pegmatite, and lamprophyre. Ground water occurs in both the glacial deposits and bedrock. Precipitation and snowmelt infiltrate to the water table on the hillsides, flow downslope through the saturated glacial deposits and fractured bedrock, and discharge to streams and to Mirror Lake. The model domain includes the glacial deposits, the uppermost 150m of bedrock, Mirror Lake, the layer of organic sediments on the lake bottom, and streams and rivers within the study area. A streamflow routing package was included in the model to simulate baseflow in streams and interaction between streams and ground water. Recharge from precipitation is assumed to be areally uniform, and riparian evapotranspiration along stream banks is assumed negligible. The spatial distribution of hydraulic conductivity is represented by dividing the model domain into several zones, each having uniform hydraulic properties. Local variations in recharge and hydraulic conductivities are ignored; therefore, the simulation results characterize the general ground-water system, not local details of ground-water movement. The model was calibrated using a nonlinear regression method to match hydraulic heads measured in piezometers and wells, and baseflow in three inlet streams to Mirror Lake. Model calibration indicates that recharge from precipitation to the water table is 26 to 28 cm/year. Hydraulic conductivities are 1.7 x 10-6 to 2.7 x 10-6 m/s for glacial deposits, about 3 x 10-7 m/s for bedrock beneath lower hillsides and valleys, and about 6x10-8 m/s for bedrock beneath upper hillsides and hilltops. Analysis of parameter uncertainty indicates that the above values are well constrained, at least within the context of regression analysis. In the regression, several attributes of the ground-water flow model are assumed perfectly known. The hydraulic conductivity for bedrock beneath upper hillsides and hilltops was determined from few data, and additional data are needed to further confirm this result. Model fit was not improved by introducing a 10-to-1 ration of horizontal-to-vertical anisotropy in the hydraulic conductivity of the glacial deposits, or by varying hydraulic conductivity with depth in the modeled part (uppermost 150m) of the bedrock. The calibrated model was used to delineate the Mirror Lake ground-water basin, defined as the volumes of subsurface through which ground water flows from the water table to Mirror Lake or its inlet streams. Results indicate that Mirror Lake and its inlet streams drain an area of ground-water recharge that is about 1.5 times the area of the surface-water basin. The ground-water basin extends far up the hillside on the northwestern part of the study area. Ground water from this area flows at depth under Norris Brook to discharge into Mirror Lake or its inlet streams. As a result, the Mirror Lake ground-water basin extends beneath the adjacent ground-water basin that drains into Norris Brook. Model simulation indicates that approximately 300,000 m3/year of precipitation recharges the Mirror Lake ground-water basin. About half the recharge enters the basin in areas where the simulated water table lies in glacial deposits; the other half enters the basin in areas where the simulated water table lies in be
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.
The purpose of this report is to appraise and evaluate the groundwater resources of a tri-state region adjacent to the lower Delaware River that is centered around Philadelphia, Pa., and Camden, N. J., and includes Wilmington, Del., and Trenton, N.J. Specifically, the region includes New Castle County, Del.; Burlington, Camden, Gloucester, Mercer, and Salem Counties in New Jersey; and Bucks, Chester, Delaware, Montgomery, and Philadelphia Counties in Pennsylvania. The peculiar advantages of ground water, such as its availability in many places without the necessity for expensive pipelines and its relatively uniform temperature and quality, make it an especially valuable resource in an industrial area. Large, readily available supplies of good, fresh water have contributed substantially to the recent rapid industrial growth of the lower Delaware River basin and will be vital to its continued prosperity. The major part of these supplies is drawn from the streams passing through the region, but very large quantities of ground water also are used. The region is divided almost equally by the Fall Line, which extends in a southwesterly direction along the general course of the Delaware River from Trenton, N.J., to Wilmington, Del., and beyond. Northwest of the Fall Line is a region of consolidated rocks in which ground water occurs mainly in cracks, crevices, and openings created or enlarged by weathering. The capacity of the various geologic formations to yield water depends largely upon the degree to which they have been fractured and weathered. The yield of individual wells in this part of the region is generally small to moderate and not readily predictable. Ground water in this part of the region is generally low in dissolved minerals and suitable for many uses without treatment. Southeast of the Fall Line lie the unconsolidated rocks of the Coastal Plain. Ground water occurs in these rocks largely in the pore spaces between the individual mineral grains. The major formations and the principal aquifers are rather uniform in their water-bearing characteristics over large areas. The yield of individual wells is moderate to very large and may be predicted with a reasonable degree of assurance. Sufficient quantities of ground water are available in most places for all ordinary purposes. The chemical quality of the ground water from the Coastal Plain aquifers is generally acceptable for most uses, but objectionable quantities of iron or other minerals are found in some places, and some waters have a low pH and are corrosive. More than 40 distinct geologic formations occur in the region. They range in age from Precambrian to Recent. Nearly all will yield some water to wells. However, only about a dozen yield water freely enough to be considered major aquifers. Of these, the sands of the Raritan and Magothy formations have been developed most intensively, and the Cohansey sand appears to have the greatest capacity for additional development. The present withdrawal of ground water in the region is estimated to average more than 200 mgd, of which more than half is drawn from the aquifers in the Raritan and Magothy formations. It is estimated that additional supplies of ground water, aggregating more than 1 billion gallons a day, can be developed within the region. Furthermore, substantial additional quantities can be developed outside the region for use within it if the need should ever arise. Induced recharge from the Delaware River supplies a substantial portion of the total water drawn from the Raritan and Magothy formations. In some areas, the quality of the water from these aquifers is approaching that of the river. Increased withdrawals of water from wells along the river will tend to increase induced recharge. Thus, the maintenance of a good quality of water in the river, which is desirable for many other reasons, is imperative if the quality of the ground-water supply is to be maintained. The proposed deepening of the Delaware River channel from Philadelphia to Trenton will greatly increase the opportunity for the interchange of water between the river and the adjacent aquifers. Whether this will be beneficial or detrimental to the ground-water supplies will depend upon the quality of the water in that reach of the river. If an acceptable quality of river water is maintained, the groundwater resources of the region will be augmented. If salt water from the ocean or excessive contamination from other sources should render the river water undesirable as a source of recharge, actual and potential ground-water supplies aggregating about 250 mgd would be endangered. The danger of salt-water encroachment into the aquifers normally yielding fresh water may limit the optimum yield of some of the most important aquifers in the region. Encroachment may come either from salt water in the surface-water bodies of the region or from parts of the aquifers, normally containing salt water. The protection of ground-water supplies against salt-water encroachment can be maintained only by constant vigilance, careful distribution of the pumping from the aquifers, regular sampling of outpost wells in exposed localities, and adjustment of rates of pumping in the light of changing conditions. The maximum beneficial utilization of the ground-water resources cannot be accomplished in haphazard fashion. It must be planned and controlled on the basis of sound, current information about the hydrology of the various aquifers. Continued and, in some areas, intensified investigations of the ground-water resources of the region should form the basis for such planning and control.
Ground-water temperature data were collected by the U.S. Geological Survey in wells at and in the vicinity of the Nevada Test Site during the years 2000-2006. Periodic ground-water temperatures were collected in 166 wells. In general, periodic ground-water temperatures were measured annually in each well at 5 and 55 feet below the water surface. Ground-water temperature profiles were collected in 73 wells. Temperatures were measured at multiple depths below the water surface to produce these profiles. Databases were constructed to present the ground-water temperature data.
The U.S. Environmental Protection Agency is working with the Yankton Sioux Tribe to develop a pesticide management plan to reduce potential for contamination of ground water that may result from the use of registered pesticides. The purpose of this study was to compile technical information to support development of a pesticide management plan by the Yankton Sioux Tribe for the area within the Yankton Sioux Reservation, Charles Mix County, South Dakota. Five pesticides (alachlor, atrazine, cyanazine, metolachlor, and simazine) were selected by the U.S. Environmental Protection Agency for the management plan approach because they had been identified as probable or possible human carcinogens and they often had been associated with ground-water contamination in many areas and at high concentrations. This report provides a compilation of data to support development of a pesticide management plan. Available data sets are summarized in the text of this report, and actual data sets are provided in one Compact Disk?Read-Only Memory that is included with the report. The compact disk contains data sets pertinent to the development of a pesticide management plan. Pesticide use for the study area is described using information from state and national databases. Within South Dakota, pesticides commonly are applied to corn and soybean crops, which are the primary row crops grown in the study area. Water-quality analyses for pesticides are summarized for several surface-water sites. Pesticide concentrations in most samples were found to be below minimum reporting levels. Topographic data are presented in the form of 30-meter digital elevation model grids and delineation of drainage basins. Geohydrologic data are provided for the surficial deposits and the bedrock units. A high-resolution (30-by-30 meters) land-cover and land-use database is provided and summarized in a tabular format. More than 91 percent of the study area is used for row crops, pasture, or hay, and almost 6 percent of the study area is covered by water or wetlands. Average monthly and yearly precipitation data are summarized in a tabular format. Irrigation information associated with permitted and licensed diversion points is provided. A composite of aerial photographs of Charles Mix County is provided. This report also describes and summarizes the data sets and files, and how the data are relevant to development of a pesticide management plan.
The U.S. Geological Survey (USGS), in cooperation with the city of Ann Arbor, Mich., investigated the ground-water/ surface-water relations along the lower reaches of Honey Creek, Washtenaw County, Mich., and an unnamed tributary to Honey Creek (the discharge tributary) from June through October 2003. Streamflow in these reaches was artificially high during a naturally low-flow period due to an anthropogenic discharge. Ground-water/surface-water relations were examined by seepage runs (series of streamflow measurements for the computation of streams gains or losses) and measurements of the difference in head between the stream surface and shallow aquifer. Specific conductance and water-temperature measurements were used as ancillary data to help identify gaining and losing reaches. Three seepage runs and four runs in which hydraulic-head differences between the stream and shallow aquifer were measured (piezometer runs) were made during periods of base flow. Streamflow measurements were made at 18 sites for the seepage runs. Instream piezometers were installed at 16 sites and bank piezometers were installed at 2 sites. Two deeper instream piezometers were installed at site 13 on September 4, 2003 to collect additional data on the ground-water/surface-water relations at that site. The seepage runs indicate that the main stem of Honey Creek and the discharge tributary in the study area are overall gaining reaches. The seepage runs also indicate that smaller reaches of Honey Creek and the discharge tributary may be losing reaches and that this relation may change over time with changing hydraulic conditions. The piezometer-run measurements support the seepage-run results on the main stem, whereas piezometer-run measurements both support and conflict with seepage-run measurements on the discharge tributary. Seepage runs give an average for the reach, whereas piezometer head-difference measurements are for a specific area around the piezometer. Data that may appear to be conflicting actually may be showing that within a gaining reach there are localized areas that lose streamflow. The overall gain in streamflow along with specific measurements of head differences, specific conductance, and water temperature indicate that ground water is discharging to Honey Creek and the discharge tributary. Although reaches and areas that lose streamflow have been identified, data collected during this study cannot confirm or disprove that the loss is to the regional ground-water system.
Explore the source record for details and available documents.