USGS Science⌕ Search

SEARCH · USGS Science

Results for “Cooperator Report”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 361 records · Page 20Linked to original sources
USGS1984

Approximate water-level changes in wells in the Chicot and Evangeline aquifers, 1977-84 and 1983-84, and measured compaction, 1973-84, in the Houston-Galveston region, Texas

This report, which was prepared in cooperation with the City of Houston and Harris-Galveston Coastal Subsidence District, presents data on water-level changes during 1977-84 and 1983-84 in the Chicot and Evangeline aquifers (figs. 1-4) and data on measured compaction 1973-84 (fig. 5). Water levels in about 550 wells were used to construct the maps showing water-level changes. Compaction data were obtained from 12 wells equipped with compaction monitors (fig. 6).

Texas↗
USGS1985

Approximate water-level changes in wells in the Chichot and Evangeline aquifers, 1977-85 and 1984-85, and measured compaction, 1973-85, in the Houston-Galveston region, Texas

This report, which was prepared in cooperation with the City of Houston and the Galveston Coastal Subsidence District, present data on water-level changes during 1977-85 and 1984-85 in the Chicot and Evangeline aquifers (figs. 1-4) and data on measured compaction 1973-85 (fig. 5). Water levels in about 500 wells were used to construct the maps showing water-level changes. Compation data were obtained from 12 wells equipped with compaction monitors (fig. 6).

Texas↗
USGS1980

Approximate water-level changes in wells in the Chicot and Evangeline aquifers in the Houston-Galveston region, Texas, 1977-80 and 1979-80

This report, which was prepared in cooperation with the cities of Houston and Galveston, the Harris Galveston Coastal Subsidence Distract, and the Texas Department of Water Resources, presents data on water-level changes during 1977-80 and 1979-80 in the Chicot and Evangelina aquifers (figs. 1-4). During these periods, ground water pumping decreased in Galveston County and southern Harris County and increased in northern and western Harris County (Gabrysch, 1979). Water levels in about 550 wells were used to construct the maps showing water level changes.

Open-File Report↗
USGS1994

Bibliography of U.S. Geological Survey water-resources reports for Utah

This bibliography contains a complete listing of reports prepared by personnel of the U.S. Geological Survey from 1886 through December 31, 1993, that discuss the water resources of Utah. The reports were prepared primarily by personnel of the Water Resources Division, Utah District, in cooperation with State, other Federal, and local agencies. Several reports were prepared as a part of studies directly funded by the U.S. Geological Survey, and several were prepared by contractors for the U.S. Geological Survey. The bibliography is divided into three major parts: (1) publications of the U.S. Geological Survey; (2) publications prepared by the U.S. Geological Survey in cooperation with and published by agencies of the State of Utah; and (3) reports printed in other publications reports prepared by the U.S. Geological Survey but published by other agencies or by professional organizations. Publications of the U.S. Geological Survey still in print may be purchased from the U.S. Geological Survey, Earth Science Information Center, Open-File Reports Section, Box 25286, MS 517, Denver Federal Center, Denver, Colorado 80225. Publications that are out of print at the time of this compilation are marked with an asterisk (*). Except for water-supply papers, most publications that are out of print and unavailable for purchase may be examined at the U.S. Geological Survey Earth Science Information Center, 2222 West 2300 South, 2nd Floor, Salt Lake City, Utah 84119. Reports published by the Utah Department of Natural Resources, Divisions of Water Rights and Water Resources, are available on request from these agencies or from the U.S. Geological Survey, Water Resources Division, Room 1016 Administration Building, 1745 West 1700 South, Salt Lake City, Utah 84104. Water-Resources Bulletins of the Utah Geological Survey may be purchased from that agency at 2363 Foothill Drive, Salt Lake City, Utah 84109-1491. Inquiries as to the availability of reports listed as "reports printed in other publications" must be addressed to the professional organization or agency that published them. Most of these reports are available in larger libraries, such as the library of the University of Utah. Most open-file reports are available for inspection at the U.S. Geological Survey, Water Resources Division, Room 1016 Administration Building, 1745 West 1700 South, Salt Lake City, Utah 84104. A small number of the open-file reports that have been duplicated as Utah basic- (or hydrologic-) data reports are free on request. An index is included in this bibliography for ease of reference. Water-supply papers on the quantity and quality of ground and surface water in Utah that were published in a series are not listed separately in the index but are presented in tables 1 to 4.

Utah↗
USGS1975

Flood plains of the South Branch Shiawassee River, Livingston County, Michigan

This report presents the results of a flood-plain study of approximately 1.9 mi (3.1 km) of the South Branch Shiawassee River in Livingston County. This reach of stream s in a currently unincorporated area about 40 mi (64 km) northwest of Detroit. Although little development has taken place, the potential for development is great due to urban spread from the Detroit Metropolitan area. To implement local flood-plain management plans, areas subject to flooding must be defined. This report is intended to provide that information. The report has been prepared in cooperation with the Livingston County Planning Commission and the Michigan Department of Natural Resources The reach of river mapped extends from the south boundary of section 3, T.2 N., R.4 E., to the west bund land f Interstate Highway 96. Six maps at a scale of 1:2400 (1 in – 200 ft or 1 cm = 24 m) were prepared; the areas covered by each map are shown on figure 1. The flood-plain maps show the area that would be inundated by a flood that has an average recurrence interval of once in 100 years; for brevity such a flood is termed the “100-year flood”.

Michigan↗
USGS1982

Approximate water-level changes in wells in the Chicot and Evangeline aquifers, 1977-82 and 1981-82, and measured compaction 1973-82, in the Houston-Galveston region, Texas

This report, which was prepared in cooperation with the City of Houston, the Harris-Galveston Coastal Subsidence District, and the Texas Department of Water Resources, presents data on water-level changes during 1977-82 and 1981-82 in the Chicot and Evangeline aquifers (fig. 1-4) and data on measured compaction 1973-82 (fig. 5). During these periods, ground-water pumping decreased in Galveston County and eastern Harris County and increased in northern and western Harris County (Gabrysch and Ranzau, 1981). Water levels in about 550 wells were used to construct the maps showing water-level changes. Compaction data were obtained from nine wells equipped with compaction monitors.

Open-File Report↗
USGS1997

Hydrogeologic framework of western Cape Cod, Massachusetts

The aquifer of western Cape Cod consists of several hydrogeologic units composed of sand, gravel, silt, and clay (fig. 1) that were deposited during the late Wisconsinan glaciation of New England. The aquifer is a shallow, unconfined hydrologic system in which ground-water flows radially outward from the apex of the ground-water mound near the center of the peninsula toward the coast (fig.2). The aquifer is the sole source of water supply for the towns of Bourne, Sandwich, Falmouth, and Mashpee, and the Massachusetts Military Reservation (MMR). Previous geologic studies summarized the characteristics and relative ages of the glacial moraines and meltwater deposits and the relation of these sediments to the extent of the ice-sheet lobes during the last glaciation of southern New England (Oldale and Barlow, 1986; Hartshorn and others, 1991). Hydrogeologic studies in western Cape Cod characterized the shallow regional ground-water-flow system (LeBlanc and others, 1986) and analyzed simulated responses of the aquifer to changes in hydrologic stresses (Guswa and LeBlanc, 1985; Barlow and Hess, 1993; Masterson and Barlow, 1994; and Masterson and others, 1996). Recent concerns about widespread ground-water contamination, especially from sources on the MMR, have resulted in extensive investigations to characterize the local hydrogeology of the aquifer near the MMR (ABB Environmental Services, 1992). Masterson and others (1996) illustrated the strong influence of geology on ground-water flow and the importance of characterizing the hydrogeology to predict the migration of the contaminant plumes beneath the MMR. This report, a product of a cooperative study between the National Guard Bureau and the U.S. Geological Survey (USGS), characterizes the regional hydrogeology of the western Cape Cod aquifer on the basis of surficial glacial geology previously described by Mather and others (1940) and Oldale and Barlow (1986), and presents a new analysis of the subsurface hydrogeology. The characterization of the regional hydrogeologic framework includes a detailed analysis of the glacial sediments, including deltaic and lacustrine deposits and their sedimentary facies; a structure-contour analysis of the transition between the shallow sand and gravel deposits and the underlying fine sand, silt, and clay deposits; and a summary of the relation between lithologic characteristics (grain size and stratigraphy) and empirically determined hydraulic-conductivity values.

Massachusetts↗
USGS2014

Appendix B—The work of the United States Geological Survey and cooperating agencies on ground water for war purposes

A report by O. E. MEINZER, published as Appendix B of the annual report of the Committee for 1942–43 [Trans. Amer. Geophys. Union, Part II, pp. 418–420, 1943], describes in some detail the previous work of the United States Geological Survey and cooperating agencies on ground water for war purposes. The geologists from the staff of the Geological Survey listed in that report and several other ground‐water geologists have served in the Army during the past year on water‐supply assignments. Only sketchy and unofficial information is as yet available concerning the activities of these geologists, but it is believed that they are now all engaged in overseas theaters of warfare and that their services in water‐supply and other technical work are of substantial value. In this service they have been supported by ground‐water maps and reports furnished by the Geological Survey for the different theaters.

Eos, Transactions, American Geophysical Union↗
USGS1978

The California condor, 1966-1976: A Look at its Past and Future

The California condor (Gymnogyps californianus) was studied on about 900 field days between 1966 and 1976. In addition, some 1,000 items of literature, specimen records from 56 museums, and 3,500 reports of condor sitings by cooperators were analyzed. Distribution does not appear to have changed significantly since the 1930's, although there are some areas within the. species' range that have become unusable. Two subpopulations of condors exist, one occupying the Coast Range Mountains, and the other found in the Transverse Ranges, Tehachapi Mountains, and Sierra Nevadas. There are well-defined seasonal movements within each subpopulation area. The surviving, wild population was estimated to be 45 condors in 1976, a decline of about 20% since 1965 and probably over 50% since 1940. No reliable population estimates are available before the 1940's, but it appears that a major decline occurred between 1880 and 1920. Shooting and specimen collecting were the primary causes of the early decline, and shooting continued as a major problem into the 1960's. Recent declines are a result of inadequate production; annual surveys indicate that only 16 young have been produced since 1968. Causes of low production are unknown but inadequate food supply, environmental contaminants, and disturbance from air traffic and petroleum extraction are implicated. A recovery plan for the condor is in operation; steps have been taken to supplement food supplies, preserve nesting and roosting habitat, and protect surviving birds from man-caused mortality or disturbance. The condor's prospects of recovery in its natural habitat seem bleak; a captive propagation program is proposed to supplement wild production.

North American Fauna↗
USGS2012

Dam-breach analysis and flood-inundation mapping for Lakes Ellsworth and Lawtonka near Lawton, Oklahoma

Dams provide beneficial functions such as flood control, recreation, and reliable water supplies, but they also entail risk: dam breaches and resultant floods can cause substantial property damage and loss of life. The State of Oklahoma requires each owner of a high-hazard dam, which the Federal Emergency Management Agency defines as dams for which failure or misoperation probably will cause loss of human life, to develop an emergency action plan specific to that dam. Components of an emergency action plan are to simulate a flood resulting from a possible dam breach and map the resulting downstream flood-inundation areas. The resulting flood-inundation maps can provide valuable information to city officials, emergency managers, and local residents for planning the emergency response if a dam breach occurs. Accurate topographic data are vital for developing flood-inundation maps. This report presents results of a cooperative study by the city of Lawton, Oklahoma, and the U.S. Geological Survey (USGS) to model dam-breach scenarios at Lakes Ellsworth and Lawtonka near Lawton and to map the potential flood-inundation areas of such dam breaches. To assist the city of Lawton with completion of the emergency action plans for Lakes Ellsworth and Lawtonka Dams, the USGS collected light detection and ranging (lidar) data that were used to develop a high-resolution digital elevation model and a 1-foot contour elevation map for the flood plains downstream from Lakes Ellsworth and Lawtonka. This digital elevation model and field measurements, streamflow-gaging station data (USGS streamflow-gaging station 07311000, East Cache Creek near Walters, Okla.), and hydraulic values were used as inputs for the dynamic (unsteady-flow) model, Hydrologic Engineering Center's River Analysis System (HEC-RAS). The modeled flood elevations were exported to a geographic information system to produce flood-inundation maps. Water-surface profiles were developed for a 75-percent probable maximum flood scenario and a sunny-day dam-breach scenario, as well as for maximum flood-inundation elevations and flood-wave arrival times for selected bridge crossings. Some areas of concern near the city of Lawton, if a dam breach occurs at Lakes Ellsworth or Lawtonka, include water treatment plants, wastewater treatment plants, recreational areas, and community-services offices.

Oklahoma↗
USGS2015

Dam-breach analysis and flood-inundation mapping for selected dams in Oklahoma City, Oklahoma, and near Atoka, Oklahoma

Dams provide beneficial functions such as flood control, recreation, and storage of water supplies, but they also entail risk; dam breaches and resultant floods can cause substantial property damage and loss of life. The State of Oklahoma requires each owner of a high-hazard dam, which the Federal Emergency Management Agency defines as dams for which failure or improper operation probably will cause loss of human life, to develop an emergency action plan specific to that dam. Components of an emergency action plan are to simulate a flood resulting from a possible dam breach and map the resulting downstream flood-inundation areas. The resulting flood-inundation maps can provide valuable information to city officials, emergency managers, and local residents for planning an emergency response if a dam breach occurs. This report presents results of a cooperative study by the U.S. Geological Survey and the City of Oklahoma City to model dam-breach scenarios at 11 dams controlled and operated by Oklahoma City, Okla., and to map the potential flood-inundation areas of such dam breaches. To assist the City of Oklahoma City with completion of the emergency action plans for the 11 dams, the U.S. Geological Survey used light detection and ranging (lidar) elevation data (2004), which produced a 2-foot contour elevation map for the flood plains around Oklahoma City. A 5-meter Digital Terrain Map was used to model the flood plain below Atoka Reservoir in southeastern Oklahoma. Digital-elevation models, field survey measurements, hydraulic data, and hydrologic data (U.S. Geological Survey streamflow-gaging stations North Canadian River below Lake Overholser near Oklahoma City, Okla. [07241000], and North Canadian River at Britton Road at Oklahoma City, Okla. [07241520]), were used as inputs for the one-dimensional dynamic (unsteady-flow) models using Hydrologic Engineering Centers River Analysis System (HEC–RAS) software. The modeled flood elevations were exported to a geographic information system to produce flood-inundation maps. Water-surface profiles were developed for a 75-percent probable maximum flood dam-breach scenario and a sunny-day dam-breach scenario, as well as for maximum flood-inundation elevations and flood-wave arrival times at selected bridge crossings. Points of interest such as community-services offices, recreational areas, water-treatment plants, and wastewater-treatment plants were identified on the flood-inundation maps.

Oklahoma↗
USGS2018

Relating cyanobacteria and physicochemical water-quality properties in Willow Creek Lake, Nebraska, 2012–14

Cyanobacteria (also referred to as blue-green algae) are naturally present members of phytoplankton assemblages that may detract from beneficial uses of water because some strains produce cyanotoxins that pose health hazards to people and animals. Cyanobacteria populations observed in Willow Creek Lake during 2012 through 2014 were compared to external nutrient loading from the Willow Creek drainage basin and several other physicochemical properties within the lake, including internal nutrient loading. This report is part of a cooperative study between the U.S. Geological Survey, the Lower Elkhorn Natural Resources District, the Nebraska Department of Environmental Quality, the Nebraska Game and Parks Commission, the Nebraska Department of Natural Resources, the Nebraska Environmental Trust, and the University of Nebraska–Lincoln. Cyanobacteria concentrations were quantified using weekly microcystin sampling, intermittent algal taxonomy, and hourly in-situ phycocyanin measurements. External and internal nutrient loads, lake water physical characteristics, and local meteorological conditions were evaluated as potential causes of cyanobacterial blooms. A water balance approach that estimated Willow Creek Lake inflow and outflow volumes identified Willow Creek as the major inflow and groundwater flux as the major outflow for the lake. Nutrient concentrations from several water sources were quantified and combined with flow volumes to compute nutrient loads during the study period. Surface flows contributed most external nutrients to the lake, whereas lake nutrients were exported during groundwater losses. The main stem of Willow Creek accounted for most nitrate loads to the lake, whereas total Kjeldahl nitrogen, total phosphorus, and phosphate loads to the lake were more evenly distributed between Willow Creek and the North Tributary, a smaller drainage. Sediment core incubations determined internal phosphorus loading was a negligible component of the overall nutrient load to the lake. Cyanobacterial responses were compared to nutrient loads and other external factors that could potentially affect algal growth. A series of univariate comparisons were made by plotting those factors against phycocyanin using biweekly summaries of each and a multivariate model that incorporated seasonality and cumulative nitrate loading. Although the multivariate model only incorporated cumulative nitrate, both nitrogen and phosphorus are likely contributing to cyanobacterial population growth, and management efforts may benefit from the recognition of differences in nutrient loading characteristics between the monitored basins.

Nebraska↗
USGS2005

Effects of removing Good Hope Mill Dam on selected physical, chemical, and biological characteristics of Conodoguinet Creek, Cumberland County, Pennsylvania

The implications of dam removal on channel characteris-tics, water quality, benthic invertebrates, and fish are not well understood because of the small number of removals that have been studied. Comprehensive studies that document the effects of dam removal are just beginning to be published, but most research has focused on larger dams or on the response of a sin-gle variable (such as benthic invertebrates). This report, pre-pared in cooperation with the Conodoguinet Creek Watershed Association, provides an evaluation of how channel morphol-ogy, bed-particle-size distribution, water quality, benthic inver-tebrates, fish, and aquatic habitat responded after removal of Good Hope Mill Dam (a small 'run of the river' dam) from Conodoguinet Creek in Cumberland County, Pa. Good Hope Mill Dam was a 6-foot high, 220-foot wide concrete structure demolished and removed over a 3-day period beginning with the initial breach on November 2, 2001, at 10:00 a.m. eastern standard time. To isolate the effects of dam removal, data were collected before and after dam removal at five monitoring stations and over selected reaches upstream, within, and downstream of the impoundment. Stations 1, 2, and 5 were at free-flowing control locations 4.9 miles upstream, 2.5 miles upstream, and 5 miles downstream of the dam, respec-tively. Stations 3 and 4 were located where the largest responses were anticipated, 115 feet upstream and 126 feet downstream of the dam, respectively Good Hope Mill Dam was not an effective barrier to sedi-ment transport. Less than 3 inches of sediment in the silt/clay-size range (less than 0.062 millimeters) coated bedrock within the 7,160-foot (1.4-mile) impoundment. The bedrock within the impoundment was not incised during or after dam removal, and the limited sediment supply resulted in no measurable change in the thalweg elevation downstream of the dam. The cross-sec-tional areas at stations 3 and 4, measured 17 days and 23 months after dam removal, were within 3 percent of the area measured before removal. Some of the impounded silt/clay at station 3 and other sed-iment in the work area downstream of the dam were initially entrained over the 3-day removal period and deposited on sub-strate at station 4. Remaining silt/clay at station 3 and deposits at station 4 were transported downstream by the flows mea-sured over the 23 months after removal (daily mean flow ranged from 38 to 5,180 cubic feet per second). The median bed-parti-cle size at station 3 increased by approximately 32 millimeters in the 23-month period after removal. Bed-particle-size distri-bution at station 4 became finer when silt/clay was initially deposited but coarsened as high flows flushed it downstream; median bed-particle size was 77.7 millimeters before removal compared to 31.3 millimeters 17 days after removal and 99 mil-limeters 23 months after removal. Good Hope Mill Dam had either no effect on water-quality characteristics or the effect was so small it was masked by sea-sonal and periodic variability. Measurements of daily mean temperature, dissolved-oxygen concentration, pH, and specific conductance on a short time scale (every 15 minutes) indicate the daily range of temperature was suppressed under impounded conditions and daily extremes of temperature, dis-solved-oxygen concentration, pH, and specific conductance at station 2 were out of phase by approximately 12 hours with station 3. Once the dam was removed, the pattern at station 3 shifted and converged with the pattern at station 2. The offset before removal may be related to a lag time resulting from a decrease in velocity through the impoundment. Total nitrogen and suspended-sediment concentrations increased upon the initial dam breach but were within the range of concentrations measured from March 2001 through April 2002 over varying flow conditions at station 1. Total nitrogen concentration at station 4 was 4.66 milligrams per liter upon the initial breach of the dam,

Pennsylvania↗
USGS2020

Cooperative Fish and Wildlife Research Units program—2019 year in review postcard

Acting Chief’s Message Dear friends, I invite you to take a look at U.S. Geological Survey Circular 1463, “Cooperative Fish and Wildlife Research Units Program—2019 Year in Review,” now available at https://doi.org/10.3133/cir1463 . In this report, you will find details about the Cooperative Fish and Wildlife Research Units (CRU) program concerning fish and wildlife science, students, staffing, vacancies, research funding, outreach and training, awards, accolades, and professional services. You will also see examples of unit projects with information on how results have been or are being applied by our cooperators. Throughout the year, keep up with our research projects at https://www1.usgs.gov/coopunits/Headquarters/ . Regards, John D. Thompson

General Information Product↗
USGS1988

Geologic studies in Alaska by the U.S. Geological Survey during 1987

This volume is a continuation of the annual United States Geological Survey (USGS) Circulars reporting results of work in progress on earth science investigations in Alaska. The series began in 1975 under the title "The United States Geological Survey in Alaska - Accomplishments during 19xx" and has continued since 1986 under the present title. The 40 short papers and the feature article presented here report on some of the geologic studies undertaken in Alaska during 1987 by the USGS, cooperating agencies, and universities.

Alaska↗
USGS1979

Water-resources investigations of the U.S. Geological Survey in Colorado; fiscal year 1979

Water-resources investigations of the U.S. Geological Survey in Colorado consist of collecting water-resources data and conducting interpretive hydrologic investigations. The water-resources data and the results of the investigations are published or released by either the U.S. Geological Survey or by cooperating agen-cies. This report describes the water-resources investigations in Colorado for the 1979 fiscal year (October 1, 1978, to September 30, 1979). The U.S. Geological Survey's investigations of the water resources of Colo-rado are under the direction of James F. Blakey, District Chief. The Colorado District office is located in Building 53, Denver Federal Center, Lakewood, Colo. (fig. 1). The Colorado District has four subdistrict offices located in Grand Junction, Lakewood, Meeker, and Pueblo (fig. 1).

Colorado↗
USGS2016

Budgets and chemical characterization of groundwater for the Diamond Valley flow system, central Nevada, 2011–12

The Diamond Valley flow system consists of six hydraulically connected hydrographic areas in central Nevada. The general down-gradient order of the areas are southern and northern Monitor Valleys, Antelope Valley, Kobeh Valley, Stevens Basin, and Diamond Valley. Groundwater flow in the Diamond Valley flow system terminates at a large playa in the northern part of Diamond Valley. Concerns relating to continued water-resources development of the flow system resulted in a phased hydrologic investigation that began in 2005 by the U.S. Geological Survey in cooperation with Eureka County. This report presents the culmination of the phased investigation to increase understanding of the groundwater resources of the basin-fill aquifers in the Diamond Valley flow system through evaluations of groundwater chemistry and budgets. Groundwater chemistry was characterized using major ions and stable isotopes from groundwater and precipitation samples. Groundwater budgets accounted for all inflows, outflows, and changes in storage, and were developed for pre-development (pre-1950) and recent (average annual 2011–12) conditions. Major budget components include groundwater discharge by evapotranspiration and groundwater withdrawals; groundwater recharge by precipitation, and interbasin flow; and storage change. Groundwater in the basin-fill aquifer of the Diamond Valley flow system was mostly a calcium or sodium bicarbonate water type and generally within acceptable drinking-water standards. The general water type was similar among the individual hydrographic areas. Stable isotopes of oxygen-18 and deuterium from precipitation varied seasonally, such that enrichment from evaporation was greater during warmer months than cooler months. The isotopic signature of shallow groundwater was similar to cool season precipitation, indicating recharge was relatively recent (similar to recent climatic conditions) and was derived from cool season precipitation. Site-scale groundwater evapotranspiration was estimated from eddy-covariance and micrometeorological measurements collected at four sites and ranged from 0.15 feet per year in sparse, undisturbed shrubland to 1.13 feet per year in a grassland meadow. Vegetation indices calculated from satellite imagery and field mapping were used to define three evapotranspiration units (shrubland, grassland, and playa) and to extrapolate site-scale groundwater evapotranspiration rates to basin-scale estimates. Annual pre-development groundwater evapotranspiration for individual hydrographic areas ranged from 2,900 acre-feet per year (acre-ft/yr) in northern Monitor Valley to 35,000 acre-ft/yr in Diamond Valley. Total groundwater evapotranspiration from the Diamond Valley flow system under pre-development conditions was about 70,000 acre-ft/yr. Areas of irrigated land in the Diamond Valley flow system increased from less than 5,000 acres in the early 1960s to more than 25,000 acres in 2012 and are mostly for growing alfalfa in southern Diamond Valley. Annual (2011–12) net groundwater withdrawals for irrigation, assumed to be the volume of groundwater consumed by crops and pastureland, ranged from about 420 acre-ft/yr in Antelope Valley to 67,000 acre-ft/yr in Diamond Valley. Total net groundwater withdrawals for irrigation in the Diamond Valley flow system were about 69,000 acre-ft/yr (2011–12). Groundwater recharge, the largest inflow component to the Diamond Valley flow system, was determined as the sum of groundwater evapotranspiration and net subsurface outflow (subsurface outflow minus subsurface inflow). Annual groundwater recharge estimates ranged from 200 acre-ft/yr in Stevens Basin to 35,000 acre-ft/yr in Diamond Valley. Subsurface flow between hydrographic basins was evaluated using estimated transmissivity, groundwater-flow sections derived from remotely sensed imagery, and hydraulic gradients determined from 2012 water-level data. Subsurface outflow ranged from 0 acre-ft/yr for Diamond Valley to 3,400 acre-ft/yr for northern Monitor Valley into western Kobeh Valley. Subsurface inflow ranged from 0 acre-ft/yr for southern Monitor Valley to 4,200 acre-ft/yr for Kobeh Valley from northern Monitor and Antelope Valleys. The pre-development, steady state, groundwater budget for the Diamond Valley flow system was estimated at about 70,000 acre-ft/yr of inflow and outflow. During years 2011–12, inflow components of groundwater recharge from precipitation and subsurface inflow from adjacent basins totaled 70,000 acre-ft/yr for the DVFS, whereas outflow components included 64,000 acre-ft/yr of groundwater evapotranspiration and 69,000 acre-ft/yr of net groundwater withdrawals, or net pumpage. Spring discharge in northern Diamond Valley declined about 6,000 acre-ft/yr between pre-development time and years 2011–12. Assuming net groundwater withdrawals minus spring flow decline is equivalent to the storage change, the 2011–12 summation of inflow and storage change was balanced with outflow at about 133,000 acre-ft/yr.

Nevada↗