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At least 847 records · Page 47Linked to original sources
USGS2011

Groundwater budgets for Detrital, Hualapai, and Sacramento Valleys, Mohave County, Arizona, 2007-08

The United States Geological Survey, in cooperation with the Arizona Department of Water Resources, initiated an investigation of the hydrogeology and water resources of Detrital, Hualapai, and Sacramento Valleys in northwestern Arizona in 2005, and this report is part of that investigation. Water budgets were developed for Detrital, Hualapai, and Sacramento Valleys to provide a generalized understanding of the groundwater systems in this rural area that has shown some evidence of human-induced water-level declines. The valleys are within the Basin and Range physiographic province and consist of thick sequences of permeable alluvial sediment deposited into basins bounded by relatively less permeable igneous and metamorphic rocks. Long-term natural recharge rates (1940-2008) for the alluvial aquifers were estimated to be 1,400 acre-feet per year (acre-ft/yr) for Detrital Valley, 5,700 acre-ft/yr for Hualapai Valley, and 6,000 acre-ft/yr for Sacramento Valley. Natural discharge rates were assumed to be equal to natural recharge rates, on the basis of the assumption that all groundwater withdrawals to date have obtained water from groundwater storage. Groundwater withdrawals (2007-08) for the alluvial aquifers were less than 300 acre-ft/yr for Detrital Valley, about 9,800 acre-ft/yr for Hualapai Valley, and about 4,500 acre-ft/yr for Sacramento Valley. Incidental recharge from leaking water-supply pipes, septic systems, and wastewater-treatment plants accounted for about 35 percent of total recharge (2007-08) across the study area. Natural recharge and discharge values in this study were 24-50 percent higher than values in most previously published studies. Water budgets present a spatially and temporally "lumped" view of water resources and incorporate many sources of uncertainty in this study area where only limited data presently are available. Figures 9, 10, and 11 from this report present water budgets for Detritial, Hualapai, and Sacramento Valleys in Northwestern Arizona. These figures show average values for each water-budget component. Uncertainty is discussed but not shown on these report figures. As an aid to readers, these figures have been implemented as interactive, web-based figures here. Water-budget parameters can be varied within reasonable bounds of uncertainty and the effects those changes have on the water budget will be shown as they are varied. This can aid in understanding sensitivity-which parameters most or least affect the water budgets-and also could provide a generally improved sense of the hydrologic cycle represented in these water budgets.

Scientific Investigations Report↗
USGS1981

Surface-water resources in the Tooele 2° quadrangle, Utah

This is one of a series of maps that describe the geology and related natural resources of the Tooele 2° quadrangle. The purpose of this map is to describe on a regional scale the availability and chemical quality of surface water and to guide readers to more detailed site-specific information about the resource in this generally semiarid region. Most of the data used to compile this map were collected by the U.S. Geological Survey under cooperative programs with the Utah Departments of Natural Resources and Transportation. Those data are available in the files of the U.S. Geological Survey, Water Resources Division, Salt Lake City, Utah.

Utah↗
USGS2008

Geologic Field Notes, Geochemical Analyses, and Field Photographs of Outcrops and Rock Samples from the Big Delta B-1 Quadrangle, East-Central Alaska

The U.S. Geological Survey, in cooperation with the Alaska Department of Natural Resources Division of Mining, Land, and Water, has released a geologic map of the Big Delta B-1 quadrangle of east-central Alaska (Day and others, 2007). This companion report presents the major element oxide and trace element geochemical analyses, including those for gold, silver, and base metals, for representative rock units and for grab samples from quartz veins and mineralized zones within the quadrangle. Also included are field station locations, field notes, structural data, and field photographs based primarily on observations by W.C. Day with additions by J.M. O'Neill and B.M. Gamble, all of the U.S. Geological Survey. The data are provided in both Microsoft Excel spread sheet format and as a Microsoft Access database.

Open-File Report↗
USGS2011

Trace element, semivolatile organic, and chlorinated organic compound concentrations in bed sediments of selected streams at Fort Gordon, Georgia, February-April 2010

A spatial survey of streams was conducted from February to April 2010 to assess the concentrations of major ions, selected trace elements, semivolatile organic compounds, organochlorine pesticides, and polychlorinated biphenyls associated with the bed sediments of surface waters at Fort Gordon military installation near Augusta, Georgia. This investigation expanded a previous study conducted in May 1998 by the U.S. Geological Survey, in cooperation with the U.S. Department of the Army Environmental and Natural Resources Management Office of the U.S. Army Signal Center and Fort Gordon, that evaluated the streambed sediment quality of selected surface waters at Fort Gordon. The data presented in this report are intended to help evaluate bed sediment quality in relation to guidelines for the protection of aquatic life, and identify temporal trends in trace elements and semivolatile organic compound concentrations at streambed sites previously sampled. Concentrations of 34 major ions and trace elements and 102 semivolatile organic, organochlorine pesticide, and polychlorinated biphenyl compounds were determined in the fine-grained fraction of bed sediment samples collected from 13 of the original 29 sites in the previous study, and 22 additional sites at Fort Gordon. Three of the sites were considered reference sites as they were presumed to be located away from potential sources of contaminants and were selected to represent surface waters flowing onto the fort, and the remaining 32 nonreference sites were presumed to be located within the contamination area at the fort. Temporal trends in trace elements and semivolatile organic compound concentrations also were evaluated at 13 of the 32 nonreference sites to provide an assessment of the variability in the number of detections and concentrations of constituents in bed sediment associated with potential sources, accumulation, and attenuation processes. Major ion and trace element concentrations in fine-grained bed sediment samples from most nonreference sites exceeded concentrations in samples from reference sites at Fort Gordon. Bed sediments from one of the nonreference sites sampled contained the highest concentrations of copper and lead with elevated levels of zinc and chromium relative to reference sites. The percentage change of major ions, trace elements, and total organic carbon that had been detected at sites previously sampled in May 1998 and current bed sediment sites ranged from -4 to 8 percent with an average percentage change of less than 1 percent. Concentrations of major ions and trace elements in bed sediments exceeded probable effect levels for aquatic life (based on the amphipod Hyalella azteca) established by the U.S. Environmental Protection Agency at 46 and 69 percent of the current and previously sampled locations, respectively. The greatest frequency of exceedances for major ions and trace elements in bed sediments was observed for lead. Concentrations of semivolatile organic compounds, organochlorine pesticides, and polychlorinated biphenyls were detected in bed sediment samples at 94 percent of the sites currently sampled. Detections of these organic compounds were reported with greater frequency in bed sediments at upstream sampling locations, when compared to downstream locations. The greatest number of detections of these compounds was reported for bed sediment samples collected from two creeks above a lake. The percentage change of semivolatile organic compounds detected at previously sampled and current bed sediment sites ranged from -68 to 100 percent with the greatest percentage increase reported for one of the creeks above the lake. Concentrations of semivolatile organic compounds and polychlorinated biphenyls in bed sediments exceeded aquatic life criteria established by the U.S. Environmental Protection Agency at three sites. Contaminant compounds exceeding aquatic life criteria included fluoranthene, phenanthrene, anthracene, benzo(a)anthracene

Georgia↗
USGS2011

Assessment of coal geology, resources, and reserves in the Southwestern Powder River Basin, Wyoming

The availability of abundant new borehole data from recent coal bed natural gas development was utilized by the U.S. Geological Survey for a comprehensive evaluation of coal resources and reserves in the southwestern part of the Powder River Basin in Wyoming. This report on the Southwestern Powder River Basin assessment area represents the third area within the basin to be assessed, the first being for coal resources and reserves in the Gillette coal field in 2008, and the second for coal resources and reserves in the northern Wyoming area of the basin in 2010. There are no active coal mines in the Southwestern Powder River Basin assessment area. The only significant production is attributed to the Dave Johnston Mine, in the extreme southern part of the area, which accounted for some 104 million short tons of coal from 1959 to 2000. Several small mines were developed in the 1950s near the Lake DeSmet area in the northwestern part of the area; however, less than 25,000 short tons of coal were produced. Eight coal beds are present at depths between 1,000 and 2,000 ft in the Southwestern Powder River Basin assessment area. Portions of these coal beds might be recovered by underground mining methods in the future; however, the lack of sufficient drill data precluded an economic study to assess the potential of surface mineable coal resources. Consequently, none of the coal resources in the Southwestern Powder River Basin assessment area were designated as reserves or recoverable coal. A total of 37 coal beds were identified during this assessment, 23 of which were modeled and evaluated to determine in-place coal resources. The total original coal resource in the Southwestern Powder River Basin assessment area for these 23 coal beds, with no restrictions applied was calculated to be 369 billion short tons. Available coal resources, which are part of the original resource that is accessible for potential mine development after subtracting all restrictions, are about 341 billion short tons (92.4 percent of the total original resource). Approximately 61 percent are at depths between 1,000 and 2,000 ft, with a modeled price of about $30 per short ton. Therefore, the majority of coal resources in the South-western Powder River Basin assessment area are considered sub-economic.

Open-File Report↗
USGS1994

Water levels through 1989 in bedrock aquifers in South Dakota

The U.S. Geological Survey, in cooperation with the South Dakota Department of Environmental and Natural Resources, has collected water-level data for 237 wells completed in bedrock aquifers throughout South Dakota. The water levels are presented in hydrographs in the main body of the report and in tables in a Supplemental Information section at the end of the report. The data are organized by county, in alphabetical order.

Open-File Report↗
USGS1998

Geologic map of central (interior) Alaska

Introduction: This map and associated digital databases are the result of a compilation and reinterpretation of published and unpublished 1:250,000- and limited 1:125,000- and 1:63,360-scale mapping. The map area covers approximately 416,000 sq km (134,000 sq mi) and encompasses 25 1:250,000-scale quadrangles in central Alaska. The compilation was done as part of the U.S. Geological Survey National Surveys and Analysis project, whose goal is nationwide assemble geologic, geochemical, geophysical, and other data. This map is an early product of an effort that will eventually encompass all of Alaska, and is the result of an agreement with the Alaska Department of Natural Resources, Division of Oil And Gas, to provide data on interior basins in Alaska. A paper version of the three map sheets has been published as USGS Open-File Report 98-133. Two geophysical maps that cover the identical area have been published earlier: 'Bouguer gravity map of Interior Alaska' (Meyer and others, 1996); and 'Merged aeromagnetic map of Interior Alaska' (Meyer and Saltus, 1995). These two publications are supplied in the 'geophys' directory of this report.

Alaska↗
USGS2003

Nutrients in Shallow Ground Waters Beneath Relatively Undeveloped Areas in the Conterminous United States

Nutrient concentrations in shallow (well depth of 30 meters or less) ground waters of relatively undeveloped areas were evaluated to determine background conditions relative to agricultural and urban land uses. Lands comprising 67 percent or greater forest or range, 10 percent or less agricultural land, and 10 percent or less urban land were used to represent relatively undeveloped areas. Data subsets from the U.S. Geological Survey's National Water-Quality Assessment Program (81 wells) and retrospective studies (320 wells) yielded 75th percentile nitrate concentrations of 0.51 and 1.1 milligrams per liter, respectively, in shallow ground water beneath relatively undeveloped areas. The value of 1.1 milligrams per liter is a reasonable upper bound estimate of relative background concentration of nitrate in shallow ground waters in the United States and incorporates effects of nominal nitrogen load to susceptible aquifers. Relative background concentration of nitrate is variable and depends in part on land use, rock type, and climate. Median nitrate concentration was significantly greater in ground water beneath rangeland (1.20 milligrams per liter) than beneath forest land (0.06 milligram per liter). Median nitrate concentration in ground water beneath rangeland was 1.4-2.7 milligrams per liter in susceptible aquifers, which consist of coarse-textured deposits or fractured rock. Increased relative background concentration of nitrate in rangeland areas likely results from evaporative concentration of nominal nitrogen load associated with natural organic and inorganic sources in hydrogeologically susceptible settings.

Water-Resources Investigations Report↗
USGS1982

Evaluation of sediment yield and sediment data-collection network in the Piceance basin, northwestern Colorado

Statistical relationships were developed between suspended-sediment discharge and several regional factors of climate, physiography, and land use in the Piceance basin, northwestern Colorado. The purpose of the study was to evaluate the existing sediment collection network, especially in regard to detecting changes in suspended-sediment discharge due to the development in the basin. Spatial- and time variability were examined using multiple linear regression techniques. Because of the short period of record, monthly mean sediment loads were used to determine shifts or changes in trends due to mining and related activities in the basin. Dummy variable analysis was used to detect these premining and postmining differences in the regression lines and also to detect seasonal differences in the sediment discharge. Differences did exist in the sediment discharge from season to season and before and after mining; however, due to the variability and short period of record the cause of these differences could not be adequately determined. Part of the high variability in sediment discharge was due to variability in the water discharge. Therefore, if the network is to be improved, the emphasis needs to be on improvement of the water-discharge. The results of the monthly mean regression analysis were used in the mean monthly and mean annual analysis for determination of initial network design equations. These were only preliminary in nature and could be improved with additional data. (USGS)

Water-Resources Investigations Report↗
USGS1982

Results of hydrologic tests and water-chemistry analyses, Wells H-6A, H-6B, and H-6C, at the proposed Waste Isolation Pilot Plant site, southeastern New Mexico

Hydrologic testing was conducted at wells H-6A, H-6B, and H-6C in the northwestern part of the proposed Waste Isolation Pilot Plant site in southeastern New Mexico to define hydraulic properties of three water-bearing zones. The zones tested were the Magenta and Culebra Dolomite Members of the Rustler Formation and the Rustler Formation-Salado Formation contact. The Magenta Dolomite and the Rustler-Salado contact yield water to wells at rates less than 0.5 gallon per minute as determined from shut-in and slug tests. A transmissivity value for the Culebra Dolomite Member was obtained by conducting conventional pumping and recovery tests in well H-6B; this well was pumped at a rate of approximately 11 gallons per minute. Water samples from the Magenta Dolomite Member of the Rustler Formation had a dissolved-solids concentration of 5,760 milligrams per liter. The major chemical constituents of water samples from this zone were sulfate, sodium, and chloride. Water samples from the Culebra Dolomite Member of the Rustler Formation had dissolved-solids concentration of 52,600 milligrams per liter, and samples from the Rustler Formation-Salado Formation contact had 316,000 milligrams per liter; chloride and sodium were the major constituents in the water samples. Radium-266, a naturally occurring radioactive element, was present in samples from all three zones.

New Mexico↗
USGS1996

Relation of physical and chemical characteristics of streams to fish communities in the Red River of the North basin, Minnesota and North Dakota, 1993-95

Fish community composition was determined at 33 reaches (average length 150 meters) at 22 sites in the Red River of the North Basin during 1994. Sites were selected to represent a range of stream sizes and ecoregions within the basin. Physical and chemical characteristics (classified in data sets of instream habitat, terrestrial habitat, hydrology, and water quality) were determined for various sites for periods ranging from two to 48 years. Instream habitat measurements were made from 1993 through 1995 for 31 reaches at 19 sites. Terrestrial habitat measures of land use/land cover, soils, and riparian zones were determined from a geographical information system coverage for 23 reaches at 14 sites. The geographical information system coverage used data from aerial photographs taken from 1990 and 1991, National Wetlands Inventory data, soils maps from the Natural Resource Conservation Service, and data from the U.S. Department of Agriculture soils data base. Water chemistry data were collected from 14 sites in the basin from 1993 through 1994. Hydrologic variability was determined from U.S. Geological Survey gaging records. Correlation analysis, cluster analysis, and principal components analysis were used to determine representative variables which accounted for the most variation in each data set. The representative variables and the fish community data were analyzed with canonical correspondence analysis to determine the relative effect of each source of environmental influence on fish community composition. Instream habitat, terrestrial habitat, and hydrologic variability were analyzed together. Water chemistry data were analyzed separately due to a lack of corresponding sites. Within the instream habitat data set, measures of habitat volume (channel width and depth) and habitat diversity were most significant in explaining the variability of the fish communities. The amount of nonagricultural land and riparian zone integrity from the terrestrial habitat data set were also useful in explaining fish community composition. Variability of mean monthly discharge and the frequency of high and low discharge events during the three years prior to fish sampling were the most influential of the hydrologic variables.The first two axes of the canonical correspondence analysis accounted for 43.3 percent of the variation in the fish community and 52.5 percent of the variation in the environmental-species relation. Water-quality indicators such as the percent of fine material in suspended sediment, minimum dissolved oxygen concentrations, minimum concentrations of dissolved organic carbon, and the range of concentrations of major ions and nutrients were the variables that were most important in the canonical correspondence analysis of water-quality data with fish. No single environmental variable or data set appeared to be more important than another in explaining variation in the fish community. The environmental factors affecting the fish communities of the Red River of the North are interrelated. For the most part, instream environmental conditions (instream habitat, hydrology, and water chemistry) appear to be more important in explaining variability in fish community composition than factors related to the agricultural nature of the basin.

Minnesota, North Dakota, South Dakota↗
USGS2018

Missouri StreamStats—A water-resources web application

The U.S. Geological Survey (USGS) maintains and operates more than 8,200 continuous streamgages nationwide. Types of data that may be collected, computed, and stored for streamgages include streamgage height (water-surface elevation), streamflow, and water quality. The streamflow data allow scientists and engineers to calculate streamflow statistics, such as the 1-percent annual exceedance probability flood (also known as the 100-year flood), the mean flow, and the 7-day, 10-year low flow, which are used by managers to make informed water resource management decisions, at each streamgage location. Researchers, regulators, and managers also commonly need physical characteristics (basin characteristics) that describe the unique properties of a basin. Common uses for streamflow statistics and basin characteristics include hydraulic design, water-supply management, water-use appropriations, and flood-plain mapping for establishing flood-insurance rates and land-use zones. The USGS periodically publishes reports that update the values of basin characteristics and streamflow statistics at selected gaged locations (locations with streamgages), but these studies usually only update a subset of streamgages, making data retrieval difficult. Additionally, streamflow statistics and basin characteristics are most often needed at ungaged locations (locations without streamgages) for which published streamflow statistics and basin characteristics do not exist. Missouri StreamStats is a web-based geographic information system that was created by the USGS in cooperation with the Missouri Department of Natural Resources to provide users with access to an assortment of tools that are useful for water-resources planning and management. StreamStats allows users to easily obtain the most recent published streamflow statistics and basin characteristics for streamgage locations and to automatically calculate selected basin characteristics and estimate streamflow statistics at ungaged locations.

Missouri↗
USGS1989

Geologic studies in Alaska by the U.S. Geological Survey, 1988

This volume continues the annual series of U.S. Geological Survey (USGS) reports on geologic investigations in Alaska. Since 1975, when the first of these collections of short papers appeared under the title "The United States Geological Survey in Alaska: Accomplishments during 1975," the series has been published as USGS circulars. This bulletin departs from the circular style, in part to provide a more flexible format for longer reports with more depth of content, better documentation, and broader scope than is possible for circular articles. The 13 papers in this bulletin represent a sampling of research activities carried out in Alaska by the USGS over the past few years. The topics addressed range from mineral resource studies (including natural gas) and geochemistry, Quaternary geology, basic stratigraphic and structural problems, and the use of computer graphics in geologic map preparation, to the application of geochronology to regional tectonic problems. Geographic areas represented are numbered on figure 1 and include the North Slope (1) and Brooks Range (2, 3) of Arctic Alaska, Seward Peninsula (4), interior Alaska (5-9), and remote locations of the Alaska Peninsula (10, 11) and southeast Alaska (12, 13). Two bibliographies following the reports of investigations list (1) reports about Alaska in USGS publications released in 1988 and (2) reports about Alaska by USGS authors in publications outside the USGS in 1988. A bibliography and index of the short papers in past USGS circulars devoted to Geological Research and Accomplishments in Alaska (1975-1986) is published as USGS Open-File Report 87-420.

Alaska↗
USGS2024

Geologic map and structure sections along the southern part of the Bartlett Springs Fault Zone and adjacent areas from Cache Creek to Lake Berryessa, northern Coast Ranges, California

Introduction Located in the Coast Ranges of northern California, the Bartlett Springs Fault Zone is the easternmost fault in the San Andreas Fault system in northern California. The fault is a right-lateral, strike-slip structure considered capable of producing an earthquake of moment magnitude 7. The purpose of this mapping is to better characterize the geology and earthquake hazards associated with the southern part of the Bartlett Springs Fault Zone and to help identify any evidence of active uplift on the faults bounding the Coast Ranges. Although the area immediately surrounding the Bartlett Springs Fault Zone is sparsely populated, its southern segment presents a potential seismic hazard to northern California communities as far away as the San Francisco Bay region and Sacramento. There are also nearby water resources, mineral resources, and public lands used for public recreation. The Coast Ranges of northern California are a series of northwest-southeast-oriented mountain ranges and valleys located north of the San Francisco Bay region, between the Pacific Ocean to the west and the Sacramento Valley to the east. The region has rugged terrain, high mountain peaks that reach more than 2,400 meters above sea level, isolated and narrow valley bottoms on which most human settlements are located, and large drainage systems that tend to follow the northwest-southeast-oriented topographic grain. The physiographic character of the region is shaped by its bedrock geology, deformational history, and active faulting. The basement rocks of the northern Coast Ranges consist of the Franciscan Complex and the Great Valley complex, the latter of which consists of two informal units, the Coast Range ophiolite and the Great Valley sequence. The Franciscan Complex and the Great Valley complex are in structural contact along the Coast Range Fault, a regional-scale structure and fundamental crustal boundary. The Franciscan Complex and the Great Valley complex are superposed by active, northwest-southeast-striking strike-slip faults that are associated with seismicity swarms. These active strike-slip faults can produce moderate to large earthquakes that have moment magnitudes of 7–8. In places, these active structures bound large ranges and valleys, suggesting that much of the modern topographic expression is the result of active deformation processes. This report contains new 1:24,000-scale geologic mapping along the southern part of the Bartlett Springs Fault Zone between Clear Lake and Lake Berryessa. The map area spans 738 square kilometers in northern Napa County, southern Lake County, and parts of Yolo and Colusa Counties. The south and east borders of the map are 90 kilometers north of San Francisco and 70 kilometers west of Sacramento, respectively. The map area is within the Knoxville mining district, which has a history of mercury and gold mining dating back to the mid-19th century. The two main towns in the region, Lower Lake and Clearlake, California, are west-northwest of the map area. Approximately 71,000 people live in the cities and rural communities located within a 40-kilometer radius of the center of the map area. The bedrock geology, cross sections, and structural data presented herein are critical for evaluating the long-term evolution of the Bartlett Springs Fault Zone. This work will supplement studies on local seismic hazards, liquefaction potential, landslide hazards, earthquake geology, natural resources, groundwater resources, engineering geology, and tectonic history by providing the background information for site-specific investigations on these subjects.

California↗
USGS2017

U.S. Department of the Interior Climate Science Centers and U.S. Geological Survey National Climate Change and Wildlife Science Center—Annual report for 2016

Introduction 2016 was an exciting year for the Department of the Interior (DOI) Climate Science Centers (CSCs) and the U.S. Geological Survey (USGS) National Climate Change and Wildlife Science Center (NCCWSC). In recognition of our ongoing efforts to raise awareness and provide the scientific data and tools needed to address the impacts of climate change on fish, wildlife, ecosystems, and people, NCCWSC and the CSCs received an honorable mention in the first ever Climate Adaptation Leadership Award for Natural Resources sponsored by the National Fish, Wildlife, and Plant Climate Adaptation Strategy’s Joint Implementation Working Group. The recognition is a reflection of our contribution to numerous scientific workshops and publications, provision of training for students and early career professionals, and work with Tribes and indigenous communities to improve climate change resilience across the Nation. In this report, we highlight some of the activities that took place throughout the NCCWSC and CSC network in 2016.

Open-File Report↗
USGS2014

National requirements for improved elevation data

This report presents the results of surveys, structured interviews, and workshops conducted to identify key national requirements for improved elevation data for the United States and its territories, including coastlines. Organizations also identified and reported the expected economic benefits that would be realized if their requirements for improved elevation were met (appendixes 1–3). This report describes the data collection methodology and summarizes the findings. Participating organizations included 34 Federal agencies, 50 States and two territories, and a sampling of local governments, tribes, and nongovernmental orgnizations. The nongovernmental organizations included The Nature Conservancy and a sampling of private sector businesses. These data were collected in 2010-2011 as part of the National Enhanced Elevation Assessment (NEEA), a study to identify program alternatives for better meeting the Nation’s elevation data needs. NEEA tasks included the collection of national elevation requirements; analysis of the benefits and costs of meeting these requirements; assessment of emerging elevation technologies, lifecycle data management needs, and costs for managing and distributing a national-scale dataset and derived products; and candidate national elevation program alternatives that balance costs and benefits in meeting the Nation’s elevation requirements. The NEEA was sponsored by the National Digital Elevation Program (NDEP), a government coordination body with the U.S. Geological Survey (USGS) as managing partner that includes the National Geospatial-Intelligence Agency (NGA), the Federal Emergency Management Agency (FEMA), the Natural Resources Conservation Service (NRCS), the U.S. Army Corps of Engineers (USACE), and the National Oceanic and Atmospheric Administration (NOAA), among the more than a dozen agencies and organizations. The term enhanced elevation data as used in this report refers broadly to three-dimensional measurements of land or submerged topography, built features, vegetation structure, and other landscape detail. Additional information about NEEA and its later use in the development of a 3D Elevation Program (3DEP) can be found at http://nationalmap.gov/3DEP/index.html.

Open-File Report↗
USGS2001

Ground-water conditions in Georgia, 2000

Ground-water conditions in Georgia during 1999 and for the period of record were evaluated using data from U.S. Geological Survey ground-water-level and ground-water-quality monitoring networks. Data for 1999 included in this report are from continuous water-level records from 130 wells and chloride analyses from 14 wells. Data from one well is incomplete because data collection was discontinued. Chloride concentration in water from the Upper Floridan aquifer in most of coastal Georgia was within drinking-water standards established by the Georgia Department of Natural Resources and the U.S. Environmental Protection Agency. In the Savannah area, chloride concentration has not changed appreciably with time. However, chloride concentration in water from some wells that tap the Floridan aquifer system in the Brunswick area exceeds the drinking-water standards.

Georgia↗
USGS1972

Floods on Yahara River, Lake Kegonsa dam to county line, Dane County, Wisconsin

The State of Wisconsin, as a result of recent legislation, is establishing new, and upgrading old, minimum standards for flood-plain regulation. These standards require evaluations of the flood potential of many streams in Wisconsin. This report provides an evaluation of flood potential for the Yahara River in the 13-mile low-water channel reach from the dam at the outlet of Lake Kegonsa downstream to the county line. Prepared by the U.S. Geological Survey in cooperation with the Dane County Regional Planning Commission and the Wisconsin Department of Natural Resources, this flood-inundation study gives the computed water-surface elevations and defines the areal limits of inundation for the regional flood. The regional flood is defined by the Wisconsin Department of Natural Resources as a flood having an average frequency of occurrence of-once in 100 years and "which is representative of large floods known to have occurred generally in Wisconsin and reasonably characteristics of what can be expected to occur on a particular stream."

Wisconsin↗