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At least 469 records · Page 26Linked to original sources
USGS1963

Ground water in the Raft River Basin, Idaho, with special reference to irrigation use, 1956-60

In the Raft River basin in south-central Idaho, ground-water withdrawals for irrigation have more than doubled since 1955, when data were compiled for a comprehensive report on the area. The present report summerizes data on the ground-water use and changes in the water regimen during the intervening 5 years. Water levels have declined 10 to 20 feet in the areas of heaviest pumping and 3 to 5 feet throughout the remainder of the area. These water-level declines are related to increased ground-water pumpage and below-normal precipitation in the basin. The total pumpage during the 1960 irrigation season is estimated to be about 127,000 acre-feet, of which about half was consumed by crops or evaporated. The remainder returned to the aquifer. Irrigation development is acting to reduce the amount of underflow out of the basin. The water table can be lowered considerably more before underflow from the basin would be reduced substantially.

Idaho↗
USGS1997

Digital simulation of ground-water flow in the Warwick Aquifer, Fort Totten Indian Reservation, North Dakota

The demand for water from the Warwick aquifer, which underlies the Fort Totten Indian Reservation in northeastern North Dakota, has been increasing during recent years. Therefore, the Spirit Lake Sioux Nation is interested in resolving questions about the quantity and quality of water in the aquifer and in developing a water-management plan for future water use. A study was conducted to evaluate the surface-water and ground-water resources of the Fort Totten Indian Reservation and, in particular, the ground-water resources in the area of the Warwick aquifer. A major component of the study, addressed by this report, was to define the ground-water flow system of the aquifer. The Warwick aquifer consists of outwash deposits of the Warwick outwash plain that are as much as 30 feet thick and buried-valley deposits beneath the outwash plain that are as much as 200 feet thick. The aquifer is bounded on the north and west by end-moraine deposits and Devils Lake, on the south by the Sheyenne River Valley, and on the east by outwash deposits and ravines. The aquifer is underlain by Pierre Shale or by glacial till, clay, or silt. Ground-water gradients generally are small and rarely are more than 3 or 4 feet per mile. From 1982 to 1993, withdrawals from the Devils Lake well field averaged 1.5 cubic feet per second, and withdrawals from irrigation wells averaged 1.29 cubic feet per second. The combined discharge from springs may be about 3 cubic feet per second. During the early 1990s, the Warwick aquifer probably was in a steady-state condition with regard to storage change in the aquifer. A finite-difference, three-dimensional, ground-water flow model provided a reasonable simulation of ground-water flow in the Warwick aquifer. The aquifer was divided vertically into two layers and horizontally into a grid of 83 by 109 cells, each measuring 656 feet (200 meters) per side. The steady-state simulation was conducted using 1992 pumpage rates and October 1992 water levels. The mean absolute difference between simulated and derived water-level altitudes during final calibration of the model was 1.52 feet. The two transient simulations were conducted for 20 time intervals of 1 year each using both the small and large storage estimates, doubled 1992 pumpage from the Devils Lake well field, 1992 irrigation pumpage, and initial water-level altitudes simulated by the October 1992 steady-state simulation. In the simulation using the small storage estimate and doubled pumpage, model cells in the area of the well field went dry after 13 years. Assumptions made in the design of the model generally are supported by the digital simulation. Except in the area of Warwick Springs and smaller springs, lateral and basal boundaries of the aquifer are impermeable. The flow system is dominated by recharge and evapotranspiration. Recharge rates obtained during the calibration process were lower in topographically high areas than in topographically low areas. Hydraulic conductivity in the area of the Devils Lake well field was larger than that in the rest of the aquifer.

Water-Resources Investigations Report↗
USGS1986

Shallow ground-water conditions, Tom Green County, Texas

Most of the water needs of Tom Green County, Texas, are supplied by ground water; however, the city of San Angelo is supplied by surface water. Groundwater withdrawals during 1980 (latest year for which data are available) in Tom Green County totaled about 15,300 acre-feet, all derived from shallow aquifers. Shallow aquifers in this report refer to the ground-water system generally less than 400 feet deep that contains water with less than a 10,000 milligrams per liter concentration of dissolved solids; aquifers comprising this system include: The Leona, Comanche Peak, Trinity, Blaine, San Angelo, Choza, Bullwagon, Vale, Standpipe, and Arroyo aquifers. The current (1983) water levels in shallow aquifers in Tom Green County are relatively unchanged from those levels listed in previous reports. In most wells, the change in water level is less than 10 feet, and only a few isolated wells or areas have changes of more than 20 feet. Based on long-term hydrographs of selected wells and precipitation, water levels are directly related to precipitation and associated pumpage for irrigation. Current (1983) water levels probably are higher than normal due to the above-normal precipitation during 1980-81. Ground water in Tom Green County commonly is very hard (greater than 180 milligrams per liter as calcium carbonate), and chemical types vary in the aquifers and in different parts of the county. The concentrations of dissolved solids range from 200 to 3,000 milligrams per liter, the dissolved-chloride concentrations range from about 40 to 1,000 milligrams per liter, and the dissolved-sulfate concentrations normally range from about 25 to 600 milligrams per liter. The dissolved-nitrate concentrations in samples from eight wells ranged from 2 to 37 milligrams per liter. Five of these samples exceeded the maximum contaminant level of 10 milligrams per liter set by the U.S. Environmental Protection Agency. Of the eight water samples analyzed for minor elements, two exceeded the maximum contaminant level for selenium, and one exceeded the maximum contaminant level for manganese. Samples from three wells were analyzed for selected pesticides; no pesticides were detected. Two groups of ground-water samples were tested for bacteria in April and August 1983. The first group consisted of samples from 25 wells; no samples contained fecal-coliform bacteria, but 15 samples contained fecal-streptococci bacteria. The second group consisted of samples from 29 wells and 1 spring; twelve of these samples contained fecal-coliform bacteria and all 30 contained fecal-streptococci bacteria. Water samples from seven wells were common to both groups, and the samples tested in August contained more bacteria. Counts of fecal-coliform bacteria ranged from 0 to 26 colonies per 100 milliliters with most less than 5 colonies per 100 milliliters. Counts of fecal-streptococci bacteria ranged from 0 to 400 colonies per 100 milliliters with most less than 20 colonies per 100 milliliters. The presence of fecal-coliform and fecalstreptococci bacteria in water is only an indicator that pollution from septic systems may be present and is not a positive check for fecal pollution. Generally, the aquifers are not contaminated by septic-system effluent, however, some individual wells or localized areas could be contaminated by nearby septic systems. Using dissolved-solids concentrations as an indicator, historical and current (1983) water-quality records were compared to determine if any changes in water quality had occurred. The quality of water from Cretaceous rocks underlying the Edwards Pleateau has not changed significantly; this water is the least mineralized ground water in the county. The quality of water from the Arroyo and Bullwagon aquifers in the eastern most part of the county also has not changed significantly; dissolved-solids concentrations range from 1,500 to 2,000 milligrams per liter. In the remainder of the county, dissolved-solids concentrations have increased from 10 to 500 milligrams per liter in ground water along the river valleys and in the Li pan Flat area and increases of 500 to 1,100 milligrams per liter have occurred in ground water southeast of San Angelo, west of Twin Buttes Reservoir, and about 10 miles east of San Angelo. Locally, dissolved-solids concentrations have increased by as much as 4,530 milligrams per liter in water from individual wells. Pollution from oil-field activities may affect the quality of water in some isolated wells and in some areas in the county. No historical records are available for determining any changes in pesticides, minor elements, or bacteria.

Texas↗
USGS2007

Water-resource trends and comparisons between partial-development and October 2006 hydrologic conditions, Wood River Valley, south-central Idaho

This report analyzes trends in ground-water and surface-water data, documents 2006 hydrologic conditions, and compares 2006 and historic ground-water data of the Wood River Valley of south-central Idaho. The Wood River Valley extends from Galena Summit southward to the Timmerman Hills. It is comprised of a single unconfined aquifer and an underlying confined aquifer present south of Baseline Road in the southern part of the study area. Streams are well-connected to the shallow unconfined aquifer. Because the entire population of the area depends on ground water for domestic supply, either from domestic or municipal-supply wells, rapid population growth since the 1970s has raised concerns about the continued availability of ground and surface water to support existing uses and streamflow. To help address these concerns, this report evaluates ground- and surface-water conditions in the area before and during the population growth that started in the 1970s. Mean annual water levels in three wells (two completed in the unconfined aquifer and one in the confined aquifer) with more than 50 years of semi-annual measurements showed statistically significant declining trends. Mean annual and monthly streamflow trends were analyzed for three gaging stations in the Wood River Valley. The Big Wood River at Hailey gaging station (13139500) showed a statistically significant trend of a 25-percent increase in mean monthly base flow for March over the 90-year period of record, possibly because of earlier snowpack runoff. Both the 7-day and 30-day low-flow analyses for the Big Wood River near Bellevue gaging station (13141000) show a mean decrease of approximately 15 cubic feet per second since the 1940s, and mean monthly discharge showed statistically significant decreasing trends for December, January, and February. The Silver Creek at Sportsman Access near Picabo gaging station (13150430) also showed statistically significant decreasing trends in annual and mean monthly discharge for July through February and April from 1975 to 2005. Comparisons of partial-development (ground-water conditions from 1952 to 1986) and 2006 ground-water resources in the Wood River Valley using a geographic information system indicate that most ground-water levels for the unconfined aquifer in the study area are either stable or declining. Declines are predominant in the southern part of the study area south of Hailey, and some areas exceed what is expected of natural fluctuations in ground-water levels. Some ground-water levels rose in the northern part of the study area; however, these increases are approximated due to a lack of water-level data in the area. Ground-water level declines in the confined aquifer exceed the range of expected natural fluctuations in large areas of the confined aquifer in the southern part of the study area in the Bellevue fan. However, the results in this area are approximated due to limited available water-level data.

Idaho↗
USGS2000

Regional ground-water flow and geochemistry in the midwestern Basins and Arches aquifer system in parts of Indiana, Ohio, Michigan, and Illinois

This report synthesizes information on the regional ground-water flow and geochemistry in the Midwestern Basins and Arches aquifer system in parts of Indiana, Ohio, Michigan, and Illinois. Aquifers that compose this water-table aquifer system include glacial aquifers and an underlying, areally extensive carbonate-rock aquifer. Water within the aquifers is most commonly a Ca-Mg-HCO 3 type or a Ca-Mg-SO 4 type. In general, the distribution of hydrochemical facies within the aquifer system is controlled by the mineralogy of the aquifer material, rather than by a chemical evolution of water along general directions of regional ground-water flow. Some ground-water flow systems within the aquifer system provide base flow to streams in response to ground-water recharge events. Other (often deeper) ground-water flow systems respond minimally to variations in ground-water recharge from precipitation and provide a fairly constant supply of water to streams. Streamflow hydrographs and base-flow duration curves were used to estimate such components of base flow in selected streams for long-term steady-state conditions in the aquifer system. Mean sustained ground-water discharge (discharge from fairly stable ground-water flow systems) ranges from 3 to 50 percent of mean ground-water discharge (discharge from all ground-water flow systems) to the selected stream reaches. These percentages indicate that 50 to 97 percent of base flow in the streams within the study area can be attributed to transient ground-water flow systems, which typically have a major component of local-scale flow. Because ground-water flow across the external boundaries of the aquifer system is minimal, such percentages indicate that most ground-water flow in the aquifer system is associated with seasonally transient local flow systems. Results of a ground-water flow model that was calibrated by use of regression methods and that simulates regional flow systems within the aquifer system (approximately 10 percent of total ground-water flow in the aquifer system) indicate that most water (99 percent) in simulated regional flow systems is from recharge at the water table. Most water (78 percent) discharges from simulated regional flow systems to the principal streams. Less than 3 percent of water in simulated regional flow systems discharges to the Ohio River, Lake Erie, or downdip areas in the Illinois (structural) Basin. Simulations also indicate that most of the Midwestern Basins and Arches aquifer system is characterized by alternating regional recharge and discharge areas at intervals of less than every 10 miles along the dominant regional trends of the potentiometric surfaces in the aquifers. Such alternating regional recharge and discharge areas result in the absence of long flow paths from the very highest regional potentiometric levels to the very lowest regional potentiometric levels. The presence of tritiated ground water (less than 50 years old) across most of the aquifer system also indicates that the aquifer system receives recharge across most of the study area. The northeastern part of the aquifer system near Lake Erie differs from the rest of the system with respect to regional ground-water flow and chemistry. Specifically, part of the northeastern part of the aquifer system can be characterized as a broad area (tens of miles) of weak regional discharge (less than 0.5 inch per year). Results of the regional ground-water flow model indicate that regional flow systems have a limited ability to carry ground water away from this area; thus precipitation is prevented from recharging the regional flow systems in this part of the aquifer system. Some ground water recharged during Pleistocene glaciation was found in this area.

Illinois, Indiana, Michigan, Ohio↗
USGS1998

Application of nonlinear-regression methods to a ground-water flow model of the Albuquerque Basin, New Mexico

This report documents the application of nonlinear-regression methods to a numerical model of ground-water flow in the Albuquerque Basin, New Mexico. In the Albuquerque Basin, ground water is the primary source for most water uses. Ground-water withdrawal has steadily increased since the 1940's, resulting in large declines in water levels in the Albuquerque area. A ground-water flow model was developed in 1994 and revised and updated in 1995 for the purpose of managing basin ground- water resources. In the work presented here, nonlinear-regression methods were applied to a modified version of the previous flow model. Goals of this work were to use regression methods to calibrate the model with each of six different configurations of the basin subsurface and to assess and compare optimal parameter estimates, model fit, and model error among the resulting calibrations. The Albuquerque Basin is one in a series of north trending structural basins within the Rio Grande Rift, a region of Cenozoic crustal extension. Mountains, uplifts, and fault zones bound the basin, and rock units within the basin include pre-Santa Fe Group deposits, Tertiary Santa Fe Group basin fill, and post-Santa Fe Group volcanics and sediments. The Santa Fe Group is greater than 14,000 feet (ft) thick in the central part of the basin. During deposition of the Santa Fe Group, crustal extension resulted in development of north trending normal faults with vertical displacements of as much as 30,000 ft. Ground-water flow in the Albuquerque Basin occurs primarily in the Santa Fe Group and post-Santa Fe Group deposits. Water flows between the ground-water system and surface-water bodies in the inner valley of the basin, where the Rio Grande, a network of interconnected canals and drains, and Cochiti Reservoir are located. Recharge to the ground-water flow system occurs as infiltration of precipitation along mountain fronts and infiltration of stream water along tributaries to the Rio Grande; subsurface flow from adjacent regions; irrigation and septic field seepage; and leakage through the Rio Grande, canal, and Cochiti Reservoir beds. Ground water is discharged from the basin by withdrawal; evapotranspiration; subsurface flow; and flow to the Rio Grande, canals, and drains. The transient, three-dimensional numerical model of ground-water flow to which nonlinear-regression methods were applied simulates flow in the Albuquerque Basin from 1900 to March 1995. Six different basin subsurface configurations are considered in the model. These configurations are designed to test the effects of (1) varying the simulated basin thickness, (2) including a hypothesized hydrogeologic unit with large hydraulic conductivity in the western part of the basin (the west basin high-K zone), and (3) substantially lowering the simulated hydraulic conductivity of a fault in the western part of the basin (the low-K fault zone). The model with each of the subsurface configurations was calibrated using a nonlinear least- squares regression technique. The calibration data set includes 802 hydraulic-head measurements that provide broad spatial and temporal coverage of basin conditions, and one measurement of net flow from the Rio Grande and drains to the ground-water system in the Albuquerque area. Data are weighted on the basis of estimates of the standard deviations of measurement errors. The 10 to 12 parameters to which the calibration data as a whole are generally most sensitive were estimated by nonlinear regression, whereas the remaining model parameter values were specified. Results of model calibration indicate that the optimal parameter estimates as a whole are most reasonable in calibrations of the model with with configurations 3 (which contains 1,600-ft-thick basin deposits and the west basin high-K zone), 4 (which contains 5,000-ft-thick basin de

New Mexico↗
USGS2005

Bibliography of ground-water references for all 254 counties in Texas, 1886-2001

Preface This bibliography comprises more than 10,000 citations of ground-water references involving all 254 counties in Texas. The reference citations date from 1886 and extend into 2001. Publications and reports from more than 30 agencies, universities, water districts, geological societies, cities, consultants, and private publication outlets are included in the bibliography. The bibliographic listing is, first, alphabetical by county and, second, chronological by date of the report, from oldest to most recent. The passing years have seen a proliferation in both published and unpublished reports, and such proliferation continues to expand at an accelerating pace. All 254 counties have had groundwater studies, either cursory or detailed. Investigation and development of the ground-water resources of the State of Texas resulted in reports that appear in a variety of formats, including Federal, State, and local agency reports; scholarly, professional, and trade journals; conference proceedings; guidebooks; maps; and theses and dissertations. The end result for the person seeking ground-water information about specific Texas counties is the increasing difficulty in locating pertinent data among the many and diverse ground-water reports in which the information is recorded. This bibliography, covering a span of 115 years, should have considerable utility in guiding those individuals seeking ground-water information.

Texas↗
USGS2002

Geologic, hydrologic, and water-quality data from multiple-well monitoring sites in the Central and West Coast basins, Los Angeles County, California, 1995-2000

In 1995, the U.S. Geological Survey (USGS), in cooperation with the Water Replenishment District of Southern California (WRDSC) , began a study to examine ground-water resources in the Central and West Coast Basins in Los Angeles County, California. The study characterizes the geohydrology and geochemistry of the regional ground-water flow system and provides extensive data for evaluating ground-water management issues. This report is a compilation of geologic, hydrologic, and water-quality data collected from 24 recently constructed multiple-well monitoring sites for the period 1995–2000. Descriptions of the collected drill cuttings were compiled into lithologic logs, which are summarized along with geophysical logs—including gamma-ray, spontaneous potential, resistivity, electromagnetic induction, and temperature tool logs—for each monitoring site. At selected sites, cores were analyzed for magnetic orientation, physical and thermal properties, and mineralogy. Field and laboratory estimates of hydraulic conductivity are presented for most multiple-well monitoring sites. Periodic water-level measurements are also reported. Water-quality information for major ions, nutrients, trace elements, deuterium and oxygen-18, and tritium is presented for the multiple-well monitoring locations, and for selected existing production and observation wells. In addition, boron-11, carbon-13, carbon-14, sulfur-34, and strontium-87/86 data are presented for selected wells.

Open-File Report↗
USGS1955

Water levels in observation wells in Santa Barbara County, California; in 1954

The investigation of the ground-water resources of Santa Barbara County was continued (luring 1954 in cooperation with the Santa Barbara County Wallet Agency. Monthly water-level measurements were made in 182 wells in 6 of which automatic water-level recorders were operated. Earlier measurements covering the period 1941 through 1952 have been published in U. S. Geological Survey water-supply papers; those for 1953 are in press and have already been released locally in duplicated form. Water-Supply Paper 1068 contains tabulated descriptions for 2,246 wells in existence in 1942 in the various ground-water basins of the county. The same publication contains also many water-level measurements made prior to 1942 by the city of Santa Barbara, Santa Maria Valley Water Conservation District, San Joaquin Power Division of the Pacific GAB and Electric Co., Union Sugar Co., Union Oil Co., and other organizations and individuals. Comprehensive reports on the geology and ground-water resources of the Santa Time River basin (Upson and Thomasson, 1951), the south-coast basins (Upson, 1951), the Santa Maria Valley area (Worts, 1951), and the Cuyama Valley (Upson and Worts, 1951) have been published as Water-Supply Papers 1107, 1108 100U. and 1110-B respectively. In October 1952 "Reports on stream runoff and ground-water storage capacity, Santa Ynez River, Santa Barbara Count, Calif.," prepared respectively by Messrs. H. C. Troxell of the Surface Water Branch and H. D. Wilson, Jr., of the Ground hater Branch, U. S. Geological Survey, were released (Troxell and Wilson, 1952). In 1954 water-level measurements were made by the city of Santa Maria and the Santa Maria Valley Water Conservation District, in addition to those made by the Geological Survey, and are included in this report.

California↗
USGS1962

Water levels in observation wells in Santa Barbara County, California, in 1961

Investigation of the ground-water resources of Santa Barbara County was continued during 1961 by the U. S. Geological Survey in cooperation with the Santa Barbara County Water Agency. Monthly water-level measurements were made in 190 wells, in 9 of which automatic water-level recorders were operated. Earlier measurements, covering the period 1941 through 1955, have been published in U. S. Geological Survey Water-Supply Papers (1943-1957); those for 1956 through 1960 have been released locally in duplicated form (Muir and Merritt, 1957; Evenson, 1958; Miller, 1959; Muir, Merritt, and Miller, 1960; and Merritt, 1961). LaRocque, Jr., and others (1950) contains tabulated descriptions of 2,246 wells in existence in 1942 in the several ground-water basins of the county. The same publication also contains many water-level measurements made prior to 1942 by the city of Santa Barbara, Santa Maria Valley Water Conservation District, San Joaquin Power Division of the Pacific Gas and Electric Co., Union Sugar Co., Union Oil Co., and other organizations and individuals. Comprehensive reports on the geology and ground-water resources of the Santa Ynez River basin (Upson and Thomasson, 1951, and Wilson, 1959), the south-coast basins (Upson, 1951), the Santa Maria Valley area (Worts, 1951), and the Cuyama Valley (Upson and Worts, 1951) have been published as Water-Supply Papers 1107, 1467, 1108, 1000, and 1110-B, respectively. A similar report on the San Antonio Creek Valley is in preparation. A report on stream runoff and ground-water storage capacity of the Santa Ynez River valley (Troxell and Wilson, 1952) was released to the open file on October 1952. In addition to the water-level measurements made by the Geological Survey in 1961, measurements made by the Santa Maria Valley Water Conservation District are included in this report. Not included in this report are miscellaneous measurements made by the U. S. Bureau of Reclamation in wells along the middle reach of the Santa Ynez River between Cachuma Dam and Rucker Crossing.

California↗
USGS1979

A plan to study the aquifer system of the Central Valley of California

Unconsolidated Quaternary alluvial deposits comprise a large complex aquifer system in the Central Valley of California. Millions of acre-feet of water is pumped from the system annually to support a large and expanding agribusiness industry. Since the 1950's, water levels have been steadily declining in many areas of the valley and concern has been expressed about the ability of the entire ground-water system to support agribusiness at current levels, not to mention its ability to function at projected expansion levels. At current levels of ground-water use, an estimated 1.5 to 2 million acre-feet is withdrawn from storage each year; that is, 1.5 to 2 million acre-feet of water is pumped annually in excess of annual replenishment. The U.S. Geological Survey has initiated a 4-year study to develop geologic, hydrologic, and hydraulic information and to establish a valleywide ground-water data base that will be used to build computer models of the ground-water flow system. Subsequently, these models may be used to evaluate the system response to various ground-water management alternatives. This report describes current problems, objectives of the study, and outlines the general work to be accomplished in the study area. A bibliography of about 600 references is included. (Kosco-USGS)

California↗
USGS1984

Ground-water withdrawals from the coastal plain of New Jersey, 1956-80

Withdrawals and site data for wells with a pump capacity of 100 ,000 gallons per day or greater in the Coastal Plain of New Jersey are stored in computer files for 1956-80. The data are aggregated by computer into tables, graphs and maps to show the distribution of ground-water withdrawals. Withdrawals are reported by type of use and aquifer for each county in the Coastal Plain. Public-supply wells withdraw the largest quantity of ground water in the Coastal Plain, followed by industrial and agricultural wells. In 1980 public-supply withdrawals were about 280 million gallons per day; the maximum monthly rate was about 355 million gallons per day in July, and the lowest was about 215 million gallons per day in February. Average industrial withdrawals were about 65 million gallons per day. Ground-water withdrawals used for agriculture vary significantly during the year. In 1980, about 75 percent of the agricultural withdrawals occurred from June through September. Several aquifers are used as sources of water supply in the Coastal Plain. Five regional aquifers are the major sources of water for public-supply, industrial, or agricultural use. In decreasing order of withdrawals in 1980, in million gallons per day, they are: The Potomac-Raritan-Magothy aquifer system, 243; Kirkwood-Cohansey aquifer system, 70; Atlantic City 800-foot sand, 21; Englishtown aquifer, 12; and the Wenonah-Mount Laurel aquifer system, 5.

New Jersey↗
USGS1985

Selected hydrologic data from wells in the East Shore area of the Great Salt Lake, Utah, 1985

This report contains hydrologic data for wells collected in the East Shore area of the Great Salt Lake, Utah. It includes water-quality data, discharge measurements, water levels, and drillers* logs. The East Shore area (plate 1) includes about 430 square miles, bounded by the Wasatch Range on the east and the Great Salt Lake on the west. The first section line north of the town of Willard is the northern boundary, whereas the Davis-Salt Lake County line is the southern boundary. Most of the data in this report were collected from 1983 to 1985 by the U.S. Geological Survey in cooperation with the Utah Department of Natural Resources, Division of Water Rights. Some of the data were previously published by Smith (1961) or Bolke and Waddell (1972). The purpose of this report is to provide ground-water data for use by officials managing water resources and the general public and to supplement an interpretive report for the area that will be published later. From tables 1- 5 of this report, determinations can be made for the depth to water-bearing units, water levels in wells, well yields, or chemical quality of ground water at the sites shown on plate 1.

Utah↗
USGS1998

Lithostratigraphy, petrography, biostratigraphy, and strontium-isotope stratigraphy of the surficial aquifer system of western Collier County, Florida

In 1996, seven cores were recovered in western Collier County, southwestern Florida, to acquire subsurface geologic and hydrologic data to support ground-water modeling efforts. This report presents the lithostratigraphy, X-ray diffraction analyses, petrography, biostratigraphy, and strontium-isotope stratigraphy of these cores. The oldest unit encountered in the study cores is an unnamed formation that is late Miocene. At least four depositional sequences are present within this formation. Calculated age of the formation, based on strontium-isotope stratigraphy, ranges from 9.5 to 5.7 Ma (million years ago). An unconformity within this formation that represents a hiatus of at least 2 million years is indicated in the Old Pump Road core. In two cores, Collier-Seminole and Old Pump Road, the uppermost sediments of the unnamed formation are not dated by strontium isotopes, and, based on the fossils present, these sediments could be as young as Pliocene. In another core (Fakahatchee Strand-Ranger Station), the upper part of the unnamed formation is dated by mollusks as Pliocene. The Tamiami Formation overlies the unnamed formation throughout the study area and is represented by the Ochopee Limestone Member. The unit is Pliocene and probably includes the interval of time near the early/late Pliocene boundary. Strontium-isotope analysis indicates an early Pliocene age (calculated ages range from 5.1 to 3.5 Ma), but the margin of error includes the latest Miocene and the late Pliocene. The dinocyst assemblages in the Ochopee typically are not age-diagnostic, but, near the base of the unit in the Collier-Seminole, Jones Grade, and Fakahatchee Strand State Forest cores, they indicate an age of late Miocene or Pliocene. The molluscan assemblages indicate a Pliocene age for the Ochopee, and a distinctive assemblage of Carditimera arata and Chione cortinaria in several of the cores specifically indicates an age near the early/late Pliocene boundary. Undifferentiated sands overlie the Pliocene limestones in two cores in the southern part of the study area. Artificial fill occurs at the top of most of the cores. The hydrologic confining units penetrated by these cores are different in different parts of the study area. To the west, a hard tightly cemented dolostone forms the first major confining unit below the water table. In the eastern part of the study area, confinement is more difficult to determine. A tightly cemented sandstone, much younger than the dolostones to the west and probably not laterally connected to them, forms a slight confining unit in one core. Thick zones of poorly sorted muddy unconsolidated sands form a slight confining unit in other cores; these probably are not correlative to either the sandstone or the dolostones to the west. The age and sedimentologic observations suggest a complex compartmentalization of the surficial aquifer system in southwestern Florida. The calibrations of dinocyst and molluscan occurrences with strontium-isotope stratigraphy allows us to expand and document the reported ranges of many taxa. This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards or with the North American Stratigraphic Code. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Florida↗
USGS2018

Groundwater chemistry and water-level elevations in bedrock aquifers of the Piceance and Yellow Creek watersheds, Rio Blanco County, Colorado, 2013–16

The Piceance and Yellow Creek watersheds in Rio Blanco County, Colorado, are known to contain important energy resources (oil shale and natural gas) and mineral resources (nahcolite). The primary sources of fresh groundwater in the Piceance and Yellow Creek watersheds are bedrock aquifers in the Uinta and Green River Formations. The aquifers are divided into an upper and lower aquifer separated by a regionally extensive semiconfining layer. These aquifers provide water to streams and springs in the watersheds and are an important resource to people living and working in the area. Development of energy and mineral resources has the potential to affect the quality of groundwater in several ways. The Bureau of Land Management and the U.S. Geological Survey began groundwater monitoring in 2010 to characterize the groundwater quality and water-level elevations of shallow bedrock aquifers in the Piceance and Yellow Creek watersheds. The purpose of this report is to present ground-water chemistry and water-level elevations collected during 2013–16. Comparisons are made to data that were collected from the bedrock aquifers from 2010 to 2012 to identify the potential for changes in water quality and water-level elevations. Appreciable changes in water-level elevations and hydraulic gradient were observed in early April 2015 in two wells completed in the upper and lower aquifers. The hydraulic gradient between the two wells was consistently downward from the upper aquifer to the lower aquifer during 2010–15; however, in early April 2015, the gradient changed from downward to upward between the two aquifers. Overall, water-level elevations declined by about 14 and 11 feet in the upper and lower aquifers, respectively, from 2013 to 2016. Previously published data estimated groundwater ages at 1,200 years old in the upper aquifer and 9,600 years old in the lower aquifer. These groundwater ages indicate that ground-water was recharged over thousands of years. With such long periods of time for aquifer recharge, declines in water-level elevation over short time steps (a few months) have important implications for sustainable management of this resource. Solution mining activities or drilling for oil and natural gas in the area could be related to the changes observed in water-level elevations in these wells; however, further investigation would be needed to evaluate causation. Changes in major-ion chemistry were evaluated in the bedrock aquifer using time series plots of select major-ion data from 2010 to 2016. Major-ion chemistry was variable for a single well from 2010 to 2016 where alkalinity and sulfate were the most variable constituents. One possible explanation for the observed changes in major-ion chemistry may be that the sample depth for that well no longer represents the most appreciable flow in the borehole. On a larger scale, potential changes in flow within the borehole may indicate changes in the regional flow system. Methane and volatile organic compound concentrations were evaluated using a similar approach to that of major ions and had similar findings. Methane concentrations in wells sampled from 2010 to 2016 were generally constant. The only exception was observed at a single well where the range of methane concentrations was from 57.4 (2010) to 4.02 milligrams per liter (2013). This is the same well where changes in water-level elevation, hydraulic gradient, and major-ion chemistry were observed, providing multiple lines of evidence to indicate change in the bedrock aquifers. Sampling of a well located in an area with little energy development but where faults or fractures could provide a path for the migration of fluids indicate mixing of groundwater between the upper and lower aquifers.

Colorado↗
USGS2002

Surface-water characteristics and quality on the Osage Reservation, Osage County, Oklahoma, 1999

Concern about the effects of early oil-industry practices of surface disposal of produced-brine water prompted an investigation of the surface-water quality on the Osage Reservation. About 38,600 oil wells have been drilled on the Osage Reservation since drilling began in 1896. The Osage Reservation comprises three major drainage basins. The Caney River Basin is in the northeast, the Bird Creek Basin is in the southeast, and the Salt Creek Basin in the west. Variations in streamflow on the Osage Reservation during a year primarily result from variations in the quantity and frequency of rainfall, evapotranspiration, and reservoir operations. Most streams do not flow during low rainfall periods in late summer, early fall, and in winter. Percent of mean annual discharge is largest during March through June, averaging 54 to 62 percent and smallest during December, January, July, and August, averaging only 14 to 21 percent. The basin areas of Caney River in the reservation (251 square miles), Salt Creek (273 square miles), and Sand Creek (227 square miles) are about the same and the basin areas of the Bird Creek Basin (418 square miles) and Homily Creek Basin (383 square miles) are similar in area. One hundred forty surface-water sites were sampled once during either February, March or August 1999. The surface-drainage areas, incremental basins, between sample sites along a stream, range in size from 0.26 to 123 square miles with a median of 8.6 square miles. Total number of oil wells upgradient of the samples sites is 31,432 or 80 percent of the total in the reservation. The total number of oil wells in the Caney River Basin in the reservation (2,975 wells), Salt Creek Basin (4,619 wells), and Sand Creek Basin (3,858 wells) are about the same and the total number of oil wells in the Bird Creek Basin (8,858 wells) and Hominy Creek Basin (7,842 wells) are similar. The number of oil wells per square mile in the incremental basins ranges for 0.86 to 154. Surface-water quality monitoring had been conducted previously at two sites included in this study. Dissolved chloride concentrations for the two samples collected during 1999 were equaled or exceeded at both sites by the historical data. There is no statistically significant difference between the distribution of the dissolved chloride concentrations from the surface water and nearby ground-water samples. The surface-water quality samples had significantly lesser concentrations of dissolved solids, sulfate, and nitrite plus nitrate as nitrogen than the ground-water samples. Chloride yield, reported in tons per day per square mile, is the chloride load divided by the basin area upstream of the sample site. The mean of the chloride yields for all the samples was 0.07 ton per day per square mile. Many sample locations where yields were greater than 0.07 ton per day per square mile were areas where dissolved chloride concentrations from surface-water samples were greater than 250 milligrams per liter in an earlier water-quality investigation. An investigation of possible relations between the surface-water quality data and the oil-well construction data for the incremental basins and for 1-mile radial distance upstream in the incremental basins was conducted. The oil-well data also were grouped by the time periods of activity into pre-1930, 1930 to 1970, and post-1970. These groups attempt to account for differences in industry drilling and producing practices associated with various periods. No statistically significant correlations were found between the surface-water quality data and the oil-well construction data.

Oklahoma↗
USGS2018

Evaluation of the Source and Transport of High Nitrate Concentrations in Ground Water, Warren Subbasin, California

Ground water historically has been the sole source of water supply for the Town of Yucca Valley in the Warren subbasin of the Morongo ground-water basin, California. An imbalance between ground-water recharge and pumpage caused ground-water levels in the subbasin to decline by as much as 300 feet from the late 1940s through 1994. In response, the local water district, Hi-Desert Water District, instituted an artificial recharge program in February 1995 using imported surface water to replenish the ground water. The artificial recharge program resulted in water-level recoveries of as much as 250 feet in the vicinity of the recharge ponds between February 1995 and December 2001; however, nitrate concentrations in some wells also increased from a background concentration of 10 milligrams per liter to more than the U.S. Environmental Protection Agency (USEPA) maximum contaminant level (MCL) of 44 milligrams per liter (10 milligrams per liter as nitrogen). The objectives of this study were to: (1) evaluate the sources of the high-nitrate concentrations that occurred after the start of the artificial-recharge program, (2) develop a ground-water flow and solute-transport model to better understand the source and transport of nitrates in the aquifer system, and (3) utilize the calibrated models to evaluate the possible effect of a proposed conjunctive-use project. These objectives were accomplished by collecting water-level and water-quality data for the subbasin and assessing changes that have occurred since artificial recharge began. Collected data were used to calibrate the ground-water flow and solute-transport models. Data collected for this study indicate that the areal extent of the water-bearing deposits is much smaller (about 5.5 square miles versus 19 square miles) than that of the subbasin. These water-bearing deposits are referred to in this report as the Warren ground-water basin. Faults separate the ground-water basin into five hydrogeologic units: the west, the midwest, the mideast, the east and the northeast hydrogeologic units. Water-quality analyses indicate that septage from septic tanks is the primary source of the high-nitrate concentrations measured in the Warren ground-water basin. Water-quality and stable-isotope data, collected after the start of the artificial recharge program, indicate that mixing occurs between imported water and native ground water, with the highest recorded nitrate concentrations in the midwest and the mideast hydrogeologic units. In general, the timing of the increase in measured nitrate concentrations in the midwest hydrogeologic unit is directly related to the distance of the monitoring well from a recharge site, indicating that the increase in nitrate concentrations is related to the artificial recharge program. Nitrate-to-chloride and nitrogen-isotope data indicate that septage is the source of the measured increase in nitrate concentrations in the midwest and the mideast hydrogeologic units. Samples from four wells in the Warren ground-water basin were analyzed for caffeine and selected human pharmaceutical products; these analyses suggest that septage is reaching the water table. There are two possible conceptual models that explain how high-nitrate septage reaches the water table: (1) the continued downward migration of septage through the unsaturated zone to the water table and (2) rising water levels, a result of the artificial recharge program, entraining septage in the unsaturated zone. The observations that nitrate concentrations increase in ground-water samples from wells soon after the start of the artificial recharge program in 1995 and that the largest increase in nitrate concentrations occur in the midwest and mideast hydrogeologic units where the largest increase in water levels occur indicate the validity of the second conceptual model (rising water levels). The potential nitrate concentration resulting from a water-level rise in the midwest and mideast hydrogeologic units was estimated using a simple mixing-cell model. The estimated value is within the range of concentrations measured in samples from wells, further indicating the validity of the second conceptual model. A ground-water flow model and a solute-transport model were developed for the Warren ground-water basin for the period 1956-2001. MODFLOW-96 was used for the ground-water flow model and MOC3D was used for the solute-transport model. The model cell size is about 500 feet by 500 feet and the models were discretized vertically into three layers. The models were calibrated using a trial-and-error approach using water-level and nitrate-concentration data collected between 1956-2001. In order to better match the measured data, low fault hydraulic characteristic values were required, thereby compartmentalizing the ground-water basin. In addition, it was necessary to parameterize the specific yield distribution for the top model layer where unconfined ground-water conditions occur into three homogeneous zones. Separate sets of specific- yield values were needed to simulate the drawdown and subsequent water-level recovery. In addition, the calibrated natural recharge was about 83 acre-feet per year. The entrainment of unsaturated-zone septage was simulated as recharge having an associated nitrate concentration. The volume of recharge was a function of the measured water-level rise between 1994-98 and the moisture content of the unsaturated zone. The nitrate concentration of the recharge water was a weighted function of the assumed nitrate concentration in the infiltrating water associated with the overlying land use. The simulated hydraulic head and nitrate concentration results were in good agreement with the measured data indicating that the mechanism for the increase in nitrate concentrations was rising water levels entraining high-nitrate septage in the unsaturated-zone. The calibrated models were used to simulate the possible effects of a planned conjunctive-use project in the western part of the ground-water basin. The simulated project included the addition of a new recharge pond and a new extraction well. In addition, recharge at two existing recharge ponds was increased and three existing production wells were pumped, treated in a nitrate-removal facility, and used for water supply. The simulated hydraulic heads increased in the west, the mideast, and parts of the east hydrogeologic units; however, the simulated hydraulic heads decreased in the midwest and northeast hydrogeologic units. The simulated nitrate concentrations increased to above the MCL of 44 milligrams per liter (10 milligrams per liter as nitrogen) in parts of the west as a result of the increase in simulated hydraulic head. The simulated nitrate concentrations decreased in part of the midwest hydrogeologic unit as a result of the artificial recharge and pumping from the nitrate-removal wells. The simulated nitrate concentrations increased to above the MCL of 44 milligrams per liter in part of the mideast and parts of the east hydrogeologic units beneath commercial land-use areas.

California↗