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At least 325 records · Page 18Linked to original sources
USGS1976

Ground water in the Harrisburg-Halsey area, southern Willamette Valley, Oregon

The Harrisburg-Halsey area lies between the Cascade and Coast Ranges in the southern Willamette Valley in northwestern Oregon. The area consists of approximately 350 square miles (910 km 2 ) and includes a part of the lower foothills of the Coast and Cascade Ranges. Volcanic and marine sedimentary units exposed in the foothills range in age from Eocene to Miocene. The volcanic rocks are primarily of dacitic and andesitic composition and yield only small quantities of water that are generally adequate only for domestic and stock use. The alluvial deposits (sand and gravel) of the valley plain contain the more productive aquifers in the area and yield most of the water that is pumped from wells in the area. Aquifers in the area are recharged principally by direct infiltration of precipitation. Most of the precipitation, which averages about 40 in. (1,020 mm) per year occurs during late autumn and winter. During 1974 the seasonal decline of water levels from winter to late summer averaged about 10 ft 13 m) for the alluvial deposits. The seasonal change of storage for 1974 was estimated to be about 170,000 acre-ft (210 hm3). Of this volume, about 14,300 acre-ft (17.6 hm 3 ) was pumped from wells; the rest, about 156,000 acre-ft (190 hm 3 ), was discharged naturally by seepage and spring flow to streams and by evapotranspiration. The difference between pumpage and natural discharge indicates that a large quantity of additional water is available for development. The storage capacity of the alluvial aquifers is estimated to be about 800,000 acre-ft (1,000 hm 3 ) in the zone 10-100 ft (3-30 m} below land surface. Ground water from the alluvial deposits is chemically suitable for irrigation and other uses, as is most of the water obtained from perched-water bodies in the older sedimentary and volcanic rocks. However, the mineral concentration of water from the older sedimentary rocks, particularly from deeper producing zones beneath the valley plain, is greater than that of water from the alluvial deposits. Locally, some of the water from the older rocks is too saline for general use. Water samples from domestic wells were analyzed for fecal coliform bacteria. Although these analyses did not indicate ground-water pollution, further study would be required to establish that none exists in the area.

Oregon↗
USGS2008

Hydrogeology, Chemical Characteristics, and Transport Processes in the Zone of Contribution of a Public-Supply Well in York, Nebraska

In 2001, the U.S. Geological Survey, as part of the National Water Quality Assessment (NAWQA) Program, initiated a topical study of Transport of Anthropogenic and Natural Contaminants (TANC) to PSW (public-supply wells). Local-scale and regional-scale TANC study areas were delineated within selected NAWQA study units for intensive study of processes effecting transport of contaminants to PSWs. This report describes results from a local-scale TANC study area at York, Nebraska, within the High Plains aquifer, including the hydrogeology and geochemistry of a 108-square-kilometer study area that contains the zone of contribution to a PSW selected for study (study PSW), and describes factors controlling the transport of selected anthropogenic and natural contaminants to PSWs. Within the local-scale TANC study area, the High Plains aquifer is approximately 75 m (meter) thick, and includes an unconfined aquifer, an upper confining unit, an upper confined aquifer, and a lower confining unit with lower confined sand lenses (units below the upper confining unit are referred to as confined aquifers) in unconsolidated alluvial and glacial deposits overlain by loess and underlain by Cretaceous shale. From northwest to southeast, land use in the local-scale TANC study area changes from predominantly irrigated agricultural land to residential and commercial land in the small community of York (population approximately 8,100). For the purposes of comparing water chemistry, wells were classified by degree of aquifer confinement (unconfined and confined), depth in the unconfined aquifer (shallow and deep), land use (urban and agricultural), and extent of mixing in wells in the confined aquifer with water from the unconfined aquifer (mixed and unmixed). Oxygen (delta 18O) and hydrogen (delta D) stable isotopic values indicated a clear isotopic contrast between shallow wells in the unconfined aquifer (hereinafter, unconfined shallow wells) and most monitoring wells in the confined aquifers (hereinafter, confined unmixed wells). Delta 18O and delta D values for a minority of wells in the confined aquifers were intermediate between those for the unconfined shallow wells and those for the confined unmixed wells. These intermediate values were consistent with mixing of water from unconfined and confined aquifers (hereinafter, confined mixed wells). Oxidation-reduction conditions were primarily oxic in the unconfined aquifer and variably reducing in the confined aquifers. Trace amounts of volatile organic compounds (VOC), particularly tetrachloroethylene (PCE) and trichloroethylene (TCE), were widely detected in unconfined shallow urban wells and indicated the presence of young urban recharge waters in most confined mixed wells. The presence of degradation products of agricultural pesticides (acetochlor and alachlor) in some confined mixed wells suggests that some fraction of the water in these wells also was the result of recharge in agricultural areas. In the unconfined aquifer, age-tracer data (chlorofluorocarbon and sulfur hexafluoride data, and tritium to helium-3 ratios) fit a piston-flow model, with apparent recharge ages ranging from 7 to 48 years and generally increasing with depth. Age-tracer data for the confined aquifers were consistent with mixing of 'old' water, not containing modern tracers recharged in the last 60 years, and exponentially-mixed 'young' water with modern tracers. Confined unmixed wells contained less than (<) 3 percent (%) young water mixed with a much larger fraction greater than or equal to (>=) 97% of old water. Confined mixed wells contained >30% young water and mean ages ranged from 12 to 14 years. Median concentrations of nitrate (as nitrogen, hereinafter, nitrate-N) were 17.3 and 16.0 mg/L (milligram per liter) in unconfined shallow urban and agricultural wells, respectively, indicating a range of likely nitrate sources. Septic systems are most numerous near the edge of the urban area and appear to be

Scientific Investigations Report↗
USGS1962

Ground-water resources of Camas Prairie, Camas and Elmore Counties, Idaho

Camas Prairie is an eastward-trending intermontane basin along the north flank of the Snake River Plain in southern Idaho. The basin is about 40 miles long and averages about 8 miles wide. It was formed as a structural depression in which a considerable thickness of alluvial and lake deposits accumulated behind basalt flows, which at times blocked the outlet to the east. Intrusive and extrusive rocks of Cretaceous to Quarternary age enclose the basin on the north, west, and east. The enclosing rocks yield small amounts of water to springs and wells from the weathered mantle and fractures. The principal aquifers are sand and gravel in the alluvial fill, and basalt. Water in the shallow deposits is not confined, and the water table generally is less than 10 feet below the surface at most places. Ground water in the deeper deposits occurs chiefly in two horizons that comprise the upper and lower artesian aquifers. Throughout much of the prairie, the pressure is sufficient that water will flow from wells in these aquifers. Recharge to the basin is from direct precipitation and percolation of stream runoff from the bordering mountains. Ground water moves from the higher areas at the base of the encircling mountains toward the center of the basin and the eastern outlet. The artesian aquifers leak by upward percolation through the imperfectly confining beds and help maintain the shallow water table. Basalt, which interfingers with the alluvial deposits, is an important aquifer near the southeast margin of the prairie and at the east end. Annual recharge to the artesian aquifers is estimated to be about 40,000 acre-feet. Discharge from the artesian aquifers is about equally divided between upward leakage to the shallow aquifers and underflow out of the prairie. Most of the underflow discharges into Camas Creek or Magic Reservoir east of the prairie; little of the underflow reaches the Snake River Plain. Wells drilled for irrigation generally yield 500 to 1,200 gallons per minute from the artesian aquifers. Better construction and development methods would result in considerably better yields. Wells drilled in the basalt will yield 2,000 to 3,000 gallons per minute with moderate drawdowns. Computations made using aquifer coefficients, estimated on the basis of data collected during the investigation, suggest that 12,000 acre-feet of ground water might be withdrawn annually. However, the aquifers are limited in areal extent, and productivity of the alluvial aquifers is not great. Consequently heavy development would result in large drawdowns in wells, and there would be much interference between wells. The postulated large withdrawals from wells on the prairie would be supplied in part by a reduction in underflow from the prairie and in part by a decrease in leakage from the artesian aquifers, which in turn would cause a decline in the shallow water table.

Water Supply Paper↗
USGS1939

Artesian-water levels and interference between artesian wells in the vicinity of Lehi, Utah

In the vicinity of Lehi, Utah, about 25 miles south of Salt Lake City, supplies of artesian water are obtained at depths of 75 to 750 feet from beds of sand and gravel of Pleistocene age. Individual beds are probably lenticular and irregular in shape, as is characteristic of the stream and lake deposits in many parts of the Lake Bonneville Basin. The artesian supplies are obtained from aquifers or groups of aquifers that are more thoroughly separated by impermeable materials than the artesian aquifers of some other ground-water areas in Utah. Most of the wells are between 130 and 200 feet deep. The artesian area in the vicinity of Lehi is only a small part of a ground-water unit that probably includes most of Utah Lake Valley. The ground-water reservoir in Utah Lake Valley was seriously depleted after the years of subnormal precipitation that culminated in the drought of 1934. However, in the vicinity of Lehi the static levels in 1934 were about the same as during 1904, a year which marked the culmination of a previous drought period. The water levels in the summer of 1935 were about the same as in 1934, indicating that the recharge to the ground-water reservoir was again sufficient to balance the discharge; and during the following year there was a marked rise of the water level in all wells, commonly 5 to 10 feet in amount. The static levels in the vicinity of Lehi fluctuate each year through a range of as much as 15 feet and are ordinarily highest during March or April and lowest during August or September. This fluctuation is due in part to the closing of flowing irrigation wells during the winter. A series of tests was made to determine the extent of interference between artesian wells. Among the wells that are between 130 and 200 feet deep, the operation of certain wells was found to cause a change in the static level in wells as much as 1 1/5 miles distant. The operation of these shallower wells, however, had no apparent effect upon the static level in the wells more than about 200 feet deep nor did the operation of these deeper wells appear to affect the static level in the shallow wells. The deep and shallow aquifers thus appear to be separated by fairly continuous beds of impermeable material.

Utah↗
USGS2008

Spatial and temporal trends in nitrate concentrations in the eastern San Joaquin Valley regional aquifer and implications for fertilizer management

Ground-water withdrawals in the San Joaquin Valley totaled 64 million m 3 /day (19 million ac-ft) in 2000, supplying about 45% of agricultural irrigation demand and about 80% of municipal supply (Hutson et al., 2004). Most of the population and ground-water use are in the eastern San Joaquin Valley, where reliance on ground water is expected to increase as a result of rapid population growth and limited surface water supplies. Protection of ground-water quality for future use requires monitoring and understanding the mechanisms controlling the long-term quality of ground water in the regional aquifer system. Nitrate has been widely detected above background concentrations in ground water in the eastern San Joaquin Valley. Nitrate concentrations (reported as nitrogen in this paper) were above the MCL of 10 mg/L in 24% of domestic wells screened in the shallow part of the aquifer that were sampled during 1993–95 (Dubrovsky et al., 1998) and the Central Valley is one of the top three regions in the state in terms of the number of public drinking-water wells exceeding the MCL for nitrate (California State Water Resources Control Board, 2002). To assess spatial and temporal trends in nitrate concentrations in the eastern San Joaquin Valley and to evaluate the long-term effects of nitrogen fertilizer use on ground-water quality in this region, data were evaluated at multiple spatial scales. Data from regional-scale monitoring networks were used to map the regional occurrence of nitrate and to determine whether shallow ground water containing elevated nitrate is migrating to deeper parts of the aquifer system. At the local scale, mean ground-water ages from analysis of age-dating tracers were combined with concentrations of nitrate to reconstruct nitrate inputs in recharge through time and to compare with estimated nitrogen applications. Ground-water flow and transport simulations of a typical public-supply well screened from about 100 to 400 ft below the water table were used to evaluate long-term concentrations beneath agricultural areas under different nitrogen management scenarios.

California↗
USGS2006

A conceptual model of ground-water flow in the eastern Snake River Plain aquifer at the Idaho National Laboratory and vicinity with implications for contaminant transport

Ground-water flow in the west-central part of the eastern Snake River Plain aquifer is described in a conceptual model that will be used in numerical simulations to evaluate contaminant transport at the Idaho National Laboratory (INL) and vicinity. The model encompasses an area of 1,940 square miles (mi2) and includes most of the 890 mi2 of the INL. A 50-year history of waste disposal associated with research activities at the INL has resulted in measurable concentrations of waste contaminants in the aquifer. A thorough understanding of the fate and movement of these contaminants in the subsurface is needed by the U.S. Department of Energy to minimize the effect that contaminated ground water may have on the region and to plan effectively for remediation. Three hydrogeologic units were used to represent the complex stratigraphy of the aquifer in the model area. Collectively, these hydrogeologic units include at least 65 basalt-flow groups, 5 andesite-flow groups, and 61 sedimentary interbeds. Three rhyolite domes in the model area extend deep enough to penetrate the aquifer. The rhyolite domes are represented in the conceptual model as low permeability, vertical pluglike masses, and are not included as part of the three primary hydrogeologic units. Broad differences in lithology and large variations in hydraulic properties allowed the heterogeneous, anisotropic basalt-flow groups, andesite-flow groups, and sedimentary interbeds to be grouped into three hydrogeologic units that are conceptually homogeneous and anisotropic. Younger rocks, primarily thin, densely fractured basalt, compose hydrogeologic unit 1; younger rocks, primarily of massive, less densely fractured basalt, compose hydrogeologic unit 2; and intermediate-age rocks, primarily of slightly-to-moderately altered, fractured basalt, compose hydrogeologic unit 3. Differences in hydraulic properties among adjacent hydrogeologic units result in much of the large-scale heterogeneity and anisotropy of the aquifer in the model area, and differences in horizontal and vertical hydraulic conductivity in individual hydrogeologic units result in much of the small-scale heterogeneity and anisotropy of the aquifer in the model area. The inferred three-dimensional geometry of the aquifer in the model area is very irregular. Its thickness generally increases from north to south and from west to east and is greatest south of the INL. The interpreted distribution of older rocks that underlie the aquifer indicates large changes in saturated thickness across the model area. The boundaries of the model include physical and artificial boundaries, and ground-water flows across the boundaries may be temporally constant or variable and spatially uniform or nonuniform. Physical boundaries include the water-table boundary, base of the aquifer, and northwest mountain-front boundary. Artificial boundaries include the northeast boundary, southeast-flowline boundary, and southwest boundary. Water flows into the model area as (1) underflow (1,225 cubic feet per second (ft3/s)) from the regional aquifer (northeast boundary-constant and nonuniform), (2) underflow (695 ft3/s) from the tributary valleys and mountain fronts (northwest boundary-constant and nonuniform), (3) precipitation recharge (70 ft3/s) (constant and uniform), streamflow-infiltration recharge (95 ft3/s) (variable and nonuniform), wastewater return flows (6 ft3/s) (variable and nonuniform), and irrigation-infiltration recharge (24 ft3/s) (variable and nonuniform) across the water table (water-table boundary-variable and nonuniform), and (4) upward flow across the base of the aquifer (44 ft3/s) (uniform and constant). The southeast-flowline boundary is represented as a no-flow boundary. Water flows out of the model area as underflow (2,037 ft3/s) to the regional aquifer (southwest boundary-variable and nonuniform) and as ground-water withdrawals (45 ft3/s) (water table boundary-variable and nonuniform). Ground-water flow i

Scientific Investigations Report↗
USGS1949

Progress report on the geology and ground-water hydrology of the lower Platte River Valley, Nebraska, with a section on the chemical quality of the ground water

The occurrence of abundant ground-water supplies in the lower Platte River Valley has made possible the present agricultural and industrial economy of the area. Likewise, the future development of the area is dependent on the wise use of this important resource. The current investigation, on which this report is based, is a necessary step in the planning for the greatest ultimate utilization of the water resources in the lower Platte River Valley. The area covered by this study is the floor of the lower Platte River Valley between North Platte and Fremont and embraces about 2,500 square miles. The entire valley floor is underlain by unconsolidated Pleistocene sediments which consist of clay, silt, sand and gravel and range in thickness from less than 20 feet to nearly 200 feet. Westward from Cozad these sediments were deposited in a valley entrenched in bedrock, but east of Cozad they are continuous with similar deposits which underlie the adjacent uplands. Bedrock formations of Tertiary age are in contact with the basal Pleistocene sediments from the west end of the area to about Central City. From Central City eastward, formations of Cretaceous age immediately underlie the Pleistocene deposits. The Pleistocene sediments and underlying pervious formations are water saturated below depths which range from less than 1 foot to about 90 feet below the surface. In general, the configuration of the water table is similar to the topography of the land surface, but the relief on the water table is considerably less by comparison. Movement of ground water is either toward the river or parallel to it. Based on present information, movement of ground water out of the valley is not indicated but additional water-level control is needed south of the valley between Grand Island and Columbus to determine the possibility of ground-water loss in this stretch of the valley. Periodic observations of water-table fluctuations have constituted an important phase of ground-water studies in the lower Platte River Valley. Examination of water-level data collected by the Geological Survey in cooperation with the Conservation and Survey Division of the University of Nebraska indicates that water levels throughout most of the valley between Gothenburg and Grand Island declined during the 9-year period, December 1930 to December 1939. The maximum net declines observed during this period were a little greater than 4 feet. During the period December 1939 to December 1946, water levels recovered throughout much of the same area; in local areas on the south side of the Platte River between North Platte and Overton water levels rose in excess of 10 feet as a result of seepage losses tram canals and irrigated lands. However, north of Wood River in western Hall County water levels continued to decline to the extent that in at least 3 observation wells water levels in December 1946 were more than 5 feet lower than in December 1930. Water levels were measured monthly in 1946 and bimonthly in 1947 in observation wells located throughout the area covered by this report. During this period water levels fluctuated through a range of about 3 feet, the lowest levels being reached in September 1946 and the highest levels being reached in July 1947. Average fluctuations between successive measurements were a little less than 0.4 foot. The amount of ground-water discharge in the summer months of 1947 was approximately double that of the previous summer. However, replenishment to groundwater storage during the fall of 1946 and the spring of 1947 was sufficiently great that the amount of water in storage in the valley as a whole at the end of the 2-year period was essentially equal to the amount in storage at the beginning of the period. At the end of 1947 the Dawson and Buffalo County areas showed gains to storage whereas the remainder of the valley suffered vary slight losses during the same 2 years. The quantity of ground water that a water-bearing material will yield is dependent upon the hydrologic properties of the material. Two hydrologic properties of greatest importance are permeability and specific yield. During the course of the present investigation 5 pumping tests were conducted to determine the coefficients of permeability and storage of the Pleistocene deposits. The values of the former range from 955 to 4,925 and the latter tram 0.007. to 0.236 attar 24 hours of pumping. The mineral character of the ground water has been determined from analyses of samples, of which 15 represented municipal supplies and 3 were irrigation waters. Ground waters analyzed for this report contained variable amounts of dissolved solids ranging from 240 to 1,060 parts per million, with hardness values above limits considered desirable tor public supplies. The increased concentration of dissolved solids for ground waters in the western part of the valley as a result of return flow conditions, is noted. Ground waters in the valley are discussed as to suitability for municipal and irrigation uses, and analyses of samples do not reveal any serious condition that would adversely affect the use of these waters for the purposes intended. As irrigation increases, periodic chemical analyses of ground waters in this area will be required to evaluate the effects of the re-use of drainage waters and to provide information for salinity control. Ground-water supplies are drawn upon extensively for irrigation purposes, for municipal supplies, and for rural, domestic and stock supplies. Nearly 4,000 irrigation wells are known to exist in the area, the greatest concentrations of these being in Dawson, Buffalo, and Hall Counties.

Nebraska↗
USGS1965

Geology and water resources of Portage County, Wisconsin

Portage County has abundant resources of generally good quality water and, although water problems exist locally, depletion or general scarcity of water is not likely in the foreseeable future. The county receives annually about 31 inches of precipitation, of which about 21 inches is lost as evaportranspiration. The average annual water yield is about 10.6 inches and consists of about 10.3 inches of runoff to streams, about 0.2 inch of water which leaves the county as underflow, and about 0.1 inch of water which is used consumptively. The surface-water resources include 104 lakes, about 110 miles of streams that discharge about 600 cfs (cubic feet per second) to the Wisconsin, Waupaca, and Little Wolf Rivers, and the Wisconsin River which has an average flow of about 2.400 cfs. Extensive deposits of outwash sand and gravel, sandy till, and alluvium release annually about 460 cfs of ground water to the streams. The principal source of ground water is thick deposits of glacial drift that occur over all but the northwestern part of the county. Although as much as 100 feet of sandstone underlies the drift in the southern part, it is not an important aquifer. Impermeable crystalline rocks of Precambrian age underlie all the aquifers and limit the downward movement of water. The county has been divided into areas having similar geologic and hydrologic conditions. These areas are here named the "sand-plain province," the "drift province," and the "drift-crystalline-rock province." The sand-plain province and the eastern part of the drift province have the greatest potential for development of large ground-water supplies. Wells yielding 1,000 to 2,000 gpm (gallons per minute) can be developed in the sand-plain province and wells yielding about 500 gpm can be developed in the drift province. Nearly all the communities in the county have water resources adequate for future expansion. An exception to this is Junction City where only a limited supply of poor quality water is readily available. Additional supplies can be developed from ground water in the Mill Creek area or from the Wisconsin River. In the sand-plain and drift provinces, ground-water runoff is about 9 inches a year and surface runoff is about 1 inch a year and of short duration. In the drift-crystalline-rock province, however, ground-water runoff is about 2 inches a year and surface runoff is about 8 inches a year and varies greatly in rate of flow. Surface and ground water are closely interrelated throughout the county and constitute a single resource. Streams, lakes, and marshes are the visible part of the ground-water surface and ground water moves slowly and continuously toward these surface points of discharge. Pumping for irrigation has temporarily lowered water levels in the vicinity of wells but has not lowered regional water levels. Pumpage has intercepted and utilized some of the recharge that would have been rapidly discharged from the aquifer, but it has not materially depleted the flow of streams. The 1955-59 decline in water levels and lake stages is attributed to a deficiency in precipitation and not to the increased pumpage from irrigation wells. To prevent excessive declines in water levels, high-capacity wells should be adequately spaced about 2,500 feet between wells pumping 1,000 gpm for 90 days. In the Stevens Point area, heavy pumping of wells near the Plover River induces recharge to ground water and thus reduces local declines in the water level. The chemical quality of ground water is generally good, but, locally, hard water and undesirable amounts of iron require treatment.

Wisconsin↗
USGS1967

Geology and ground-water resources of Laramie County, Wyoming

Laramie County, an area of 2,709 square miles, is in the southeast corner of Wyoming. Rocks exposed there range in age from Precambrian to Recent. The most extensive aquifers in the county are the White River Formation of Oligocene age, which is as much as 500 feet thick and consists predominantly of siltstone ; the Arikaree Formation of Miocene age, which consists of as much as 450 feet of very fine grained to fine-grained sandstone; and the Ogallala Formation of Miocene and Pliocene age, which consists ,of as much as 330 feet of gravel, sand, silt, and some cobbles and boulders. These formations are capable of yielding large ,supplies of water locally. Terrace deposits of Quaternary age yield moderate .to large supplies of water in the southeastern and northeastern parts of the county. In the Federal well field, large yields of water from the White River Formation are obtained from gravel lenses. In the eastern part of the county near Pine Bluffs, large yields are obtained from openings in .the siltstone of the White River. Previous investigators reported that the large yields were obtained in areas where the formation is fractured and fissured. The authors of this report believe that .the large yields from siltstone in the White River Formation are from pipes, sometimes called natural tunnels, rather than from fractures ,or fissures. Little is known about the water-bearing properties of the pro-Tertiary aquifers in the county, but water derived from the pro-Tertiary formations would probably be of poor quality, except in the vicinity of the outcrop near the western edge of the county. Precipitation is the principal source of recharge to the ground-water reservoirs. About 5 percent of the annual precipitation, or about 108,400 acre-feet per year, is estimated to be recharged. Only a small amount of additional recharge is from streams. The general movement of ground water is eastward, and the average gradient of the water table is about 40 feet per mile. The total amount ,of ground water pumped from wells in Laramie County during 1964 is estimated to be 28,000 acre-feet; about 6,000 acre-feet was used for municipal and industrial supplies, about 17,000 acre-feet was used for irrigation in the Pine Bluffs-Carpenter area, and about 5,000 acre-feet was used for other purposes. The balance of the recharge (80,400 acre-feet) is estimated to be discharged by the following means: 20 percent by underflow, 20 percent by streamflow, and 60 percent by evapotranspiration. The coefficient of transmissibility of the Ogallala Formation, determined by averaging data from 28 pumping tests made in the Cheyenne municipal well field, is about 16,000 gallons per day per foot. However, this figure is an average of the more permeable zones, and the average coefficient of transmissibility of the Ogallala in the county is probably much less because of the heterogeneous character of the formation. A coefficient of transmissibility of 3,800 gallons per day per foot was calculated for the Ogallala, in the same vicinity that the pumping tests were made, by using a regional method of analysis. Although the average transmissibility of the Ogallala is considered to be low, large yields are obtained from gravel stringers and lenses in the formation. The maximum perennial yield from the Cheyenne well field is estimated to be about 1.6 billion gallons per year. Moderate to large yields of water can be obtained in the north-central part of the county where the saturated thickness of the Arikaree Formation, or combined Arikaree and Ogallala Formations, is 200 feet or more. Ground water has been developed throughout the county, but development has been intensive only in the Cheyenne municipal well fields near Cheyenne and Federal and in the Pine Bluffs lowland. The water level has been lowered as much as 40 feet in the Cheyenne well field and somewhat less in the Federal well field.

Wyoming↗
USGS2013

Geology, water-quality, hydrology, and geomechanics of the Cuyama Valley groundwater basin, California, 2008--12

To assess the water resources of the Cuyama Valley groundwater basin in Santa Barbara County, California, a series of cooperative studies were undertaken by the U.S. Geological Survey and the Santa Barbara County Water Agency. Between 2008 and 2012, geologic, water-quality, hydrologic and geomechanical data were collected from selected sites throughout the Cuyama Valley groundwater basin. Geologic data were collected from three multiple-well groundwater monitoring sites and included lithologic descriptions of the drill cuttings, borehole geophysical logs, temperature logs, as well as bulk density and sonic velocity measurements of whole-core samples. Generalized lithologic characterization from the monitoring sites indicated the water-bearing units in the subsurface consist of unconsolidated to partly consolidated sand, gravel, silt, clay, and occasional cobbles within alluvial fan and stream deposits. Analysis of geophysical logs indicated alternating layers of finer- and coarser-grained material that range from less than 1 foot to more than 20 feet thick. On the basis of the geologic data collected, the principal water-bearing units beneath the monitoring-well sites were found to be composed of younger alluvium of Holocene age, older alluvium of Pleistocene age, and the Tertiary-Quaternary Morales Formation. At all three sites, the contact between the recent fill and younger alluvium is approximately 20 feet below land surface. Water-quality samples were collected from 12 monitoring wells, 27 domestic and supply wells, 2 springs, and 4 surface-water sites and were analyzed for a variety of constituents that differed by site, but, in general, included trace elements; nutrients; dissolved organic carbon; major and minor ions; silica; total dissolved solids; alkalinity; total arsenic and iron; arsenic, chromium, and iron species; and isotopic tracers, including the stable isotopes of hydrogen and oxygen, activities of tritium, and carbon-14 abundance. Of the 39 wells sampled, concentrations of total dissolved solids and sulfate from 38 and 37 well samples, respectively, were greater than the U.S. Environmental Protection Agency’s secondary maximum contaminant levels. Concentrations greater than the maximum contaminant levels for nitrate were observed in five wells and were observed for arsenic in four wells. Differences in the stable-isotopic values of hydrogen and oxygen among groundwater samples indicated that water does not move freely between different formations or between different zones within the Cuyama Valley. Variations in isotopic composition indicated that recharge is derived from several different sources. The age of the groundwater, expressed as time since recharge, was between 600 and 38,000 years before present. Detectable concentrations of tritium indicated that younger water, recharged since the early 1950s, is present in parts of the groundwater basin. Hydrologic data were collected from 12 monitoring wells, 56 domestic and supply wells, 3 surface-water sites, and 4 rainfall-gaging stations. Rainfall in the valley averaged about 8 inches annually, whereas the mountains to the south received between 12 and 19 inches. Stream discharge records showed seasonal variability in surface-water flows ranging from no-flow to over 1,500 cubic feet per second. During periods when inflow to the valley exceeds outflow, there is potential recharge from stream losses to the groundwater system Water-level records included manual quarterly depth-to-water measurements collected from 68 wells, time-series data collected from 20 of those wells, and historic water levels from 16 wells. Hydrographs of the manual measurements showed declining water levels in 16 wells, mostly in the South-Main zone, and rising water levels in 14 wells, mostly in the Southern Ventucopa Uplands. Time-series hydrographs showed daily, seasonal, and longer-term effects associated with local pumping. Water-level data from the multiple-well monitoring sites indicated seasonal fluctuations as great as 80 feet and water-level differences between aquifers as great as 40 feet during peak pumping season. Hydrographs from the multiple-well groundwater monitoring sites showed vertical hydraulic gradients were upward during the winter months and downward during the irrigation season. Historic hydrographs showed water-level declines in the Southern-Main, Western Basin, Caliente Northern-Main, and Southern Sierra Madre zone ranging from 1 to 7 feet per year. Hydrographs of wells in the Southern Ventucopa Uplands zone showed several years with marked increases in water levels that corresponded to increased precipitation in the Cuyama Valley. Investigation of hydraulic properties included hydraulic conductivity and transmissivity estimated from aquifer tests performed on 63 wells. Estimates of horizontal hydraulic conductivity ranged from about 1.5 to 28 feet per day and decreased with depth. The median estimated hydraulic conductivity for the older alluvium was about five times that estimated for the Morales Formation. Estimates of transmissivity ranged from 560 to 163,400 gallons per day per foot and decreased with depth. The median estimated transmissivity for the younger alluvium was about three times that estimated for the older alluvium. Geomechanical analysis included land-surface elevation changes at five continuously operating global positioning systems (GPS) and land-subsidence detection at five interferometric synthetic aperture radar (InSAR) reference points. Analysis of data collected from continuously operating GPS stations showed the mountains to the south and west moved upward about 1 millimeter (mm) annually, whereas the station in the center of the Southern-Main zone moved downward more than 7 mm annually, indicating subsidence. It is likely that this subsidence is inelastic (permanent) deformation and indicates reduced storage capacity in the aquifer sediments. Analysis of InSAR data showed local and regional changes that appeared to be dependent, in part, on the time span of the interferogram, seasonal variations in pumping, and tectonic uplift. Long-term InSAR time series showed a total maximum detected subsidence rate of approximately 12 mm per year at one location and approximately 8 mm per year at a second location, while short-term InSAR time series showed maximum subsidence of about 15 mm at one location and localized maximum uplift of about 10 mm at another location.

California↗
USGS2014

Groundwater and surface-water resources in the Bureau of Land Management Moab Master Leasing Plan area and adjacent areas, Grand and San Juan Counties, Utah, and Mesa and Montrose Counties, Colorado

The Bureau of Land Management (BLM) Canyon Country District Office is preparing a leasing plan known as the Moab Master Leasing Plan (Moab MLP) for oil, gas, and potash mineral rights in an area encompassing 946,469 acres in southeastern Utah. The BLM has identified water resources as being potentially affected by oil, gas, and potash development and has requested that the U.S. Geological Survey prepare a summary of existing water-resources information for the Moab MLP area. This report includes a summary and synthesis of previous and ongoing investigations conducted in the Moab MLP and adjacent areas in Utah and Colorado from the early 1930s through the late 2000s. Eight principal aquifers and six confining units were identified within the study area. Permeability is a function of both the primary permeability from interstitial pore connectivity and secondary permeability created by karst features or faults and fractures. Vertical hydraulic connection generally is restricted to strongly folded and fractured zones, which are concentrated along steeply dipping monoclines and in narrow regions encompassing igneous and salt intrusive masses. Several studies have identified both an upper and lower aquifer system separated by the Pennsylvanian age Paradox Member of the Hermosa Formation evaporite, which is considered a confining unit and is present throughout large parts of the study area. Surface-water resources of the study area are dominated by the Colorado River. Several perennial and ephemeral or intermittent tributaries join the Colorado River as it flows from northeast to southwest across the study area. An annual spring snowmelt and runoff event dominates the hydrology of streams draining mountainous parts of the study area, and most perennial streams in the study area are snowmelt-dominated. A bimodal distribution is observed in hydrographs from some sites with a late-spring snowmelt-runoff peak followed by smaller peaks of shorter duration during the late summer. The large regional streams (Colorado, Green, and Dolores Rivers) integrate the regional hydrologic partitioning of a very large contributing area and, therefore, the hydrographs for these streams are much more smooth and consistent. Several streams throughout the study area are considered impaired and do not meet the standards set by the Environmental Protection Agency for specific designated-use classifications. Limited data are available to quantitatively estimate the large-scale regional groundwater budget for the study area. Previous studies have estimated groundwater budgets for areas in and adjacent to the current study area, namely Moab-Spanish Valley and parts of the Paradox Basin. Most groundwater recharge to the study area originates as infiltration of precipitation from upland areas and is further enhanced in areas covered with sandy soils or in areas where the bedrock is highly fractured. Additional groundwater recharge occurs as seepage from streams and irrigation water, and as subsurface inflow, both vertically between aquifers and as lateral movement into the study area. Groundwater discharge occurs as seepage to streams, evapotranspiration, to springs and seeps, well withdrawals; and as subsurface outflow, both vertically between aquifers and as lateral movement out of the study area across its defined boundaries. Groundwater use in the study area was determined using data from the Utah Division of Water Rights. Most wells in the study area are categorized as having multiple uses. Mean specific-conductance values for groundwater from wells and springs in the study area range from 101 to 220,000 microsiemens per centimeter at 25° C (μS/cm); most of the wells or springs have mean specific-conductance values of less than or equal to 1,000 μS/cm. Previously reported total dissolved-solids concentrations, specific conductances, and other groundwater-quality data for each of the principal aquifers indicate relative freshwater throughout the study area, except within the lower aquifer system and areas in contact with the Paradox Member of the Hermosa Formation evaporites. There is limited information on the resource availability of brines and saline groundwater in the study area. Total dissolved-solids concentrations typically are high (greater than 35,000 milligrams per liter) in groundwater from, or in contact with, the Paradox Member of the Hermosa Formation. Total dissolved-solids concentrations also are high in groundwater samples collected from the lower aquifer system. Because the Paradox Member of the Hermosa Formation is considered a barrier to vertical groundwater flow, most of the brine and saline groundwater resources are restricted to the lower aquifer system.

Colorado, Utah↗
USGS1977

Ground-water resources of Griggs and Steele Counties, North Dakota

Griggs and Steele Counties, in east-central North Dakota, are underlain by bedrock of Ordovician, Jurassic, and Cretaceous ages. The Fall River and Lakota Formations of Cretaceous age form the Dakota aquifer. The fractured upper part of the Pierre Formation (shale), also of Cretaceous age, forms another bedrock aquifer. The Dakota aquifer, which consists mainly of interbedded shale and sandstone units, may yield as much as 500 gallons per minute (32 liters per second) of sodium sulfate water to wells at selected locations. The Pierre aquifer yields from 1 to 10 gallons per minute (0.06 to 0.63 liters per second) of sodium bicarbonate or sodium sulfate water to wells. Four major glacial-drift aquifers are present in the study area. The Spiritwood aquifer system may supply as much as 1,500 gallons per minute (95 liters per second) of water to wells. Water samples contained dissolved-solids concentrations ranging from 244 to 9,800 milligrams per liter. The Galesburg aquifer will yield as much as 1,000 gallons per minute (63 liters per second) of water to wells. Water samples contained dissolved-solids concentrations ranging from 317 to 2,170 milligrams per liter. The McVille aquifer will yield as much as 500 gallons per minute (32 liters per second) to wells. Water samples contained dissolved-solids concentrations ranging from 449 to 2,200 milligrams per liter. The Elk Valley aquifer could yield 30 gallons per minute (2 liters per second) to wells. Water samples contained dissolved-solids concentrations ranging from 397 to 2,890 milligrams per liter. Six communities in the project area use ground-water supplies. Rural water districts are being developed in the two-county area that will provide dependable ground-water supplies for many farms and small municipalities. The Spiritwood aquifer system and the McVille and Galesburg aquifers are capable of supplying the water needs of these districts and could also provide water for irrigation.

North Dakota↗
USGS1986

Geohydrology and simulated response to ground-water pumpage in Carson Valley, a river-dominated basin in Douglas County, Nevada, and Alpine County, California

A numerical model was used to simulate the effect of development of the groundwater reservoir in Carson Valley on Carson River outflow, evapotranspiration, and groundwater levels and storage. The basin-fill groundwater reservoir consists of: (1) confined and unconfined sedimentary deposits of Quaternary age that underlie the valley floor, and (2) sedimentary deposits of Tertiary age that are exposed mainly on the east side of the valley. Water levels indicate the presence of two confined aquifer systems: one < 100 ft deep, and the other, generally deeper than 200 ft. The basin-fill reservoir is surrounded by bedrock that transmits recharge to the basin through weathered and fractured zones near the contact between bedrock and valley fill. Estimates were made of the distribution of hydraulic properties of aquifer materials, and of the components of inflow to and outflow from the basin-fill reservoir. Inflow components consisted of the following approximate quantities, in acre-ft/yr: (1) mainstem Carson River flow, 360,000; (2) direct precipitation, 70,000; (3) runoff from perennial and ephemeral streams, 24,000: and (4) subsurface inflow, 38,000. Approximate estimates of outflow components were, in acre-ft/yr; (1) mainstem Carson River flow, 291,000; (2) potential evapotranspiration, 200,000. Both inflow and outflow totaled about 490,000 acre-ft/yr. These flow volumes show that the hydrologic regimen of the basin is dominated by surface water flow of the Carson River. Steady-state and transient calibration of the model provided an unacceptable fit of observed versus simulated groundwater level fluctuations and storage, and surface water outflow from the valley. These values provide a reasonable balance for the simulated steady-state water budget. Simulations show that surface water flow is the ultimate source of about 75% of pumped water for six scenarios of possible future ground-water development. Model simulations indicate that changes from agricultural to urban land uses could decrease the loss of Carson River outflow to pumpage when streamflow is not used for flood irrigation in that area.

California, Nevada↗
USGS1969

Ground-water resources of the Wind River Indian Reservation, Wyoming

The area of this investigation is in the western part of the Wind River Basin and includes parts of the Absaroka, Washakie, Wind River, and Owl Creek Mountains. The purposes of the study were to determine the general hydrologic properties of the rocks in the area and the occurrence and quality c f the water in them. Structurally, the area is a downfolded basin surrounded by upfolded mountain ranges. Igneous and metamorphic rocks of Precambrian age are exposed in the mountains: folded sedimentary rocks representing all geologic periods, except the Silurian, crop out along the margins of the basin; and relatively flat-lying Tertiary rocks are at the surface in the central part of the basin. Surficial sand and gravel deposits of Quaternary age occur along streams and underlie numerous terraces throughout the basin. The potential yield and quality of water from most rocks in the area are poorly known, but estimates are possible, based on local well data and on data concerning similar rocks in nearby areas. Yields of more than 1,000 gpm are possible from the rocks comprising the Bighorn Dolomite (Ordovician), Darby Formation (Devonian), Madison Limestone (Mississippian), and Tensleep Sandstone (Pennsylvanian). Total dissolved solids in the water range from about 300 to 3,000 ppm. Yields of as much as several hundred gallons per minute are possible from the Nugget Sandstone (Jurassic? and Triassic?). Yields of 20 gpm or more are possible from the Crow Mountain Sandstone (Triassic) and Sundance Formation (Jurassic). Dissolved solids are generally high but are less than 1,000 ppm near outcrops in some locations. The Cloverly and Morrison (Cretaceous and Jurassic), Mesaverde (Cretaceous) and Lance(?) (Cretaceous) Formations may yield as much as several hundred gallons per minute, but most wells in Cretaceous rocks yield less than 20 gpm. Dissolved solids generally range from 1,000 to 5,000 ppm but may be higher. In some areas, water with less than 1,000 ppm dissolved solids may be available from the Cloverly and Morrison Formations. Tertiary rocks yield a few to several hundred gallons per minute and dissolved solids generally range from 1,000 to 5,000 ppm. Wells in the Wind River Formation (Eocene) yield about 1.-500 gpm of water having dissolved solids of about 200-5,000 ppm. Yields of a few to several hundred gallons per minute are available from alluvium (Quaternary). Dissolved solids range from about 200 to 5,000 ppm. Many parts of the Wind River Irrigation Project have become waterlogged. The relation of drainage problems to geology and the character and thickness of rocks in the irrigated areas are partly defined by sections drawn on the basis of test drilling. The drainage-problem areas are classified according to geologic similarities into five general groups: flood plains, terraces, underfit-stream valleys, slopes, and transitional areas. Drainage can be improved by open drains, buried drains, relief wells, and pumped wells or by pumping from sumps or drains. The methods that will be most successful depend on the local geologic and hydrologic conditions. In several areas, the most effective means of relieving the drainage problem would be to reduce the amount of infiltration of water by lining canals and ditches and by reducing irrigation water applications to the optimum. Water from underground storage in alluvium could supplement water from surface storage in some areas. A few thousand acre-feet of water per square mile are in storage in some of the alluvium. The use of both surface and underground storage would reduce the need for additional surface-storage facilities and also would alleviate drainage problems in the irrigated areas.

Water Supply Paper↗
USGS1955

Geology and ground-water resources of the Douglas basin, Arizona, with a section on chemical quality of the ground water

The Douglas basin is part of a large northwest-trending intermontane valley, known as the Sulphur Spring Valley, which lies in southeastern Arizona, and extends into northeastern Sonora, Mexico. Maturely dissected mountains rise abruptly from long alluvial slopes and culminate in peaks 3,000 to 4,000 feet above the valley floor, Bedrock in the mountain areas confines drainage on the east and west, and an arc of low hills to the north separates the basin from the Willcox basin of the Sulphur Spring Valley. Drainage of the 1,200 square miles in the Douglas basin is southward into Mexico through Whitewater Draw. The mountains include igneous, metamorphic, and sedimentary rocks ranging in age from pre-Cambrian to Tertiary, including Paleozoic and Mesozoic sedimentary rocks that total about 10,000 feet in thickness. The older rocks have been metamorphosed, and all the bedrock has been affected by igneous intrusion, largely in Mesozoic time, and by structural movements, largely in Cenozoic time and extending into the Quaternary period. By the early part of Cenozoic time the major structural features were formed, and mountain ranges had been uplifted above the valley trough along northwest-trending fault zones. Since that time the physiographic features have resulted through erosion of the mountain blocks and the deposition, in places, of more than 2,800 feet of unconsolidated rock debris in the valley. Ground-water supplies of the Douglas basin are developed largely in the saturated zone of the valley-fill sediments. The ground water in the valley fill occurs in thin lenses and strata of sand and gravel, which are interbedded with large thicknesses of silt and day. Scattered gypsum beds and extensive caliche deposits appear at the surface and occur within the valley fill at various depths. Although the valley-fill sediments are as much as 2,800 feet thick, the uppermost 300 feet or so are the most permeable. Ground water originates as precipitation in the mountain areas. The water collects in streams that lose much of their flow into the coarse sediments that fringe the mountains. Part of the water ultimately percolates into the zone of saturation. High evaporation rates, vegetative use, and the presence of caliche and clay at shallow depth in the interstream areas of the valley floor prevent important recharge of the ground-water reservoir from direct rainfall or seepage of water applied for irrigation. The total recharge into the ground-water reservoir of the Douglas basin was about 20,000 acre-feet in 1951. Ground water is discharged from the basin by evapotranspiration, by effluent seepage into Whitewater Draw and underflow out of the basin, and by pumping. In 1951, the total amount of ground water discharged was about 50,000 acre-feet, of which more than 41,000 acre-feet was pumped from wells. Ground water used in excess of recharge is withdrawn from storage, causing a decline in the water table. Maximum declines have occurred in the heavily pumped Elfrida area, where a decline of more than 11 feet occurred in the 5- year period 1947-51, inclusive. Most irrigation wells in the Douglas basin are less than 200 feet in depth and usually produce less than 400 gpm (gallons per minute). The average specific capacity of the wells is about 12 gpm per foot of drawdown. Although water in some parts of the basin is artesian, all irrigation wells must be pumped. Ground water in the basin is generally of excellent to good quality for irrigation use, In small areas along the southern part of Whitewater Draw and east of Douglas the ground water is high in dissolved-solids content. Although most of the water is hard, it is generally satisfactory for domestic use. In many areas the fluoride content is more than 1.5 ppm (parts per million).

Arizona↗
USGS1964

Ground-water resources of southern New Castle County, Delaware

Southern New Castle County has a land area of 190 square miles in northcentral Delaware. It is predominantly a rural area with a population of about 9,500 people who are engaged chiefly in agriculture. By and large, the residents are dependent upon ground water as a source of potable water. This investigation was made to provide knowledge of the availability and quality of .the ground-water supply to aid future development. The climate, surface features, and geology of the area are favorable for the occurrence of ground water. Temperatures are generally mild and precipitation is normally abundant and fairly evenly distributed throughout the year. The topography of the area is relatively fiat and, hence, the streams have low gradients. The surface is underlain to a considerable depth by highly permeable unconsolidated sediments that range in age from Early Cretaceous to Recent. Nearly all the subsurface stratigraphic units yield some water to wells, but only four parts or combinations of these units are sufficiently permeable, to yield large supplies. These are, from oldest to youngest, the nonmarine Cretaceous sediments and the Magothy Formation, the Monmouth Group, the Rancocas Formation, and .the surficial terrace and valley-fill deposits. In the northern part of the area the nonmarine Cretaceous sediments and the Magothy Formation can be reached economically by wells. Yields in excess of 300 gpm (gallons per minute) have been obtained from wells screened in this aquifer, but the maximum productivity of the aquifer has not been .tested. The Monmouth Group is used as a source of water in the central part of the area, where some wells yield as much as 125 gpm. The Rancocas Formation is the principal aquifer in the southern part of the area. Yields of 200-400 gpm can be expected from this aquifer, owing to its uniformly coarse texture, particularly in the upper part of the formation. The terrace deposits compose the shallow watertable aquifer throughout the area. In places the water-table aquifer is connected hydraulically to each of .the other three aquifers. The yields of wells tapping this aquifer are generally small, because the saturated thickness of the aquifer is small. The aquifer does provide a convenient and economical source of water for domestic supplies, .and the quality o# the available water supply is generally satisfactory for most purposes. The use of water in the area was estimated to be about 1.77 million gallons per day in 1959. Rural uses amounted to about 75 percent of the total, and municipal and industrial uses accounted for .the remainder. Water for irrigation of crops constituted about half of the water pumped for rural use. The total use of ground water in the area is a mere fraction of the supply available. Each of the four major aquifers is capable of vastly increased production. Future development, however, will be .limited by the changes in the quality of the water resulting from the future pumping regime-and the expanded pattern of development. Salt-water encroachment will become a problem in the eastern part of the area if steps are not taken to avoid it.

Water Supply Paper↗
USGS1964

Preliminary results of hydrogeologic investigations in the valley of the Humboldt River near Winnemucca, Nevada

Most of the ground water of economic importance and nearly all the ground water closely associated with the flow o# the Humboldt River in the. 40-mile reach near Winnemucca, Nev., are in unconsolidated sedimentary deposits. These deposits range in age from Pliocene to Recent and range in character from coarse poorly sorted fanglomerate to lacustrine strata of clay, silt, sand, and gravel. The most permeable deposit consists of sand and gravel of Lake Lahontan age--the so-called medial gravel unit--which is underlain and overlain by fairly impermeable silt and clay also of Lake Lahontan age. The ultimate source of nearly all the water in the study area is precpitation within the drainage basin of the Humboldt River. Much of this water reaches the study, area as flow or underflow of the Humboldt River and as underflow from other valleys tributary to the study area. Little if any flow from the tributary streams in the study area usually reaches the Humboldt River. Most of the tributary streamflow within the study area evaporates or is transpired by vegetation, but a part percolates downward through unconsolidated deposits of the alluvial fans flanking the mountains and move downgradient as ground-water underflow toward the Humboldt River. Areas that contribute significant amounts of ground-water underflow to. the valley of the Humboldt River within the study area are (1) the valley of the Humboldt River upstream from the study area, (2) the Pole Creek-Rock Creek area, (3) Paradise Valley, and (4) Grass Valley and the northwestern slope of the Sonoma Range. The total average underflow from these areas in the period 1949-61 was about 14,000-19,000 acre-feet per year. Much of this underflow discharged into the Humboldt River within the study area and constituted a large part of the base flow of the river. Streamflow in the Humboldt River increases substantially in the early spring, principally because of runoff to the river in the reaches upstream from the study area. The resulting increase of the stage of the river causes the river to lose large amounts of water by infiltration to the ground-water reservoir in the study area. In addition, there is much recharge to the ground-water reservoir in the spring and early summer as a result of seepage losses from irrigation ditches and the downward percolation of some of the excess water applied for irrigation. The average net increase of ground water in storage in the deposits beneath and adjacent to the flood plain of the Humboldt River during the spring and early summer is about 10,000 acre-feet.

Nevada↗
USGS1967

Ground-water conditions and geologic reconnaissance of the Upper Sevier River basin, Utah

The upper Sevier River basin is in south-central Utah and includes an area of about 2,400 .square miles of high plateaus and valleys. It comprises the entire Sevier River drainage basin above Kingston, including the East Fork Sevier River and its tributaries. The basin was investigated to determine general ground-water conditions, the interrelation of ground water and surface water, the effects of increasing the pumping of ground water, and the amount of ground water in storage. The basin includes four main valleys - Panguitch Valley, Circle Valley, East Fork Valley, and Grass Valley - which are drained by the Sevier River, the East Fork Sevier River, and Otter Creek. The plateaus surrounding the valleys consist of sedimentary and igneous rocks that range in age from Triassic to Quaternary. The valley fill, which is predominantly alluvial gravel, sand, silt, and clay, has a maximum thickness of more than 800 feet. The four main valleys constitute separate ground-water basins. East Fork Valley basin is divided into Emery Valley, Johns Valley, and Antimony subbasins, and Grass Valley basin is divided into Koosharem and Angle subbasins. Ground water occurs under both artesian and water-table conditions in all the basins and subbasins except Johns Valley, Emery Valley, and Angle subbasins, where water is only under water-table conditions. The water is under artesian pressure in beds of gravel and sand confined by overlying beds of silt and clay in the downstream parts of Panguitch Valley basin, Circle Valley basin, and Antimony subbasin, and in most of Koosharem subbasin. Along the sides and upstream ends of these basins, water is usually under water-table conditions. About 1 million acre-feet of ground water that is readily available to wells is stored in the gravel and sand of the upper 200 feet of saturated valley fill. About 570,000 acre-feet is stored in Panguitch Valley basin, about 210,000 in Circle Valley basin, about 6,000 in Emery Valley subbasin, about 90,000 in Johns Valley subbasin, about 36,000 in Antimony subbasin, about 90,000 in Koosharem subbasin, and about 60,000 in Angle subbasin. Additional water, although it is not readily available to wells, is stored in beds of silt and clay. Some ground water also is available in the bedrock underlying and surrounding the basins, although the bedrock formations generally are poor aquifers. The principal source of recharge to the valley fill in the upper Sevier River basin is infiltration from streams, canals, and irrigated fields. Some ground water also miles into the valley till from the bedrock surrounding the basins. The basin contains about 300 wells, most of which are less than 4 inches in diameter, are less than 250 feet deep, and are used for domestic purposes and stock watering. More than half the wells are flowing wells in Koosharem subbasin. Approximately 82,000 acre-feet of ground water was discharged in 1962 from the valley till. Springs discharged about 33,000 acre-feet, wells about 3,000, and drains about 3,000; and evapotranspiration from phreatophyte areas about 43,000 acre-feet. Springs in bedrock discharged an additional 75,000 acre-feet. Most of the water discharged by springs, wells, and drains was used for irrigation. The ground water in the basin generally is of good chemical quality. The water is excellent for irrigation and stock but is not as desirable for most domestic and industrial uses because of its hardness. The dissolved-solids content of the ground water generally increases slightly from the upstream end of the individual ground-water basins to. the downstream end owing mostly to repeated use of the water for irrigation. Surface water and ground water in the upper Sevier River basin are inter- connected, and the base flows of streams are affected by changes in ground- water levels. Increased pumping of ground water would result in (1) an increase in the recharge to the aquifers from surface-water sources or (2) a decrease in the discharge from streams, springs, flowing wells, and areas of phreatophytes or (3) a combination of these. About 43,000 acre-feet of ground water is now discharged annually by evapotranspiration from phreatophyte areas, and perhaps one-third of this loss, or about 14,000 acre-feet, could be salvaged by eliminating wet areas and phreatophytes. The areas where water could be salvaged are at the downstream ends of Panguitch Valley basin, Circle Valley basin, and Antimony subbasin. Most of the 14,000 acre-feet 'of water could be pumped from large-diameter wells or developed by properly designed drains without greatly affecting stream- flow and with only moderate effect on 'spring discharge. If the wells were properly located, the pumping would lower water levels and dry up wet areas where phreatophytes grow. Conjunctive use of ground water and surface water would facilitate the more efficient use of all water resources in the basin

Utah↗