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At least 757 records · Page 42Linked to original sources
USGS1996

Statistical summaries of streamflow data for selected gaging stations in Idaho and adjacent states through September 1990 - Volume 1: Gaging stations with 10 or more years of record

This volume presents statistical summaries of streamflow data for 257 gaging stations with 10 or more years of continuous record through September 1990. The gaging stations are located in Idaho and adjacent States. Volume 2 presents statistical summaries of streamflow data for 76 gaging stations with 5 to 9 years of continuous record, or with records of discharge measurements from springs, through September 1990. The gaging stations are located in Idaho and western Wyoming. Streamflow statistics generated for gaging stations with 10 or more years of record were (1) magnitudes of monthly and annual flows; (2) magnitudes and frequencies of daily low, high, instantaneous peak (flood frequency), and annual mean flows; (3) duration of daily mean flows; and (4) maximum, median, and minimum daily mean flows. Streamflow statistics generated for gaging stations with 5 to 9 years of record or that measure discharge from springs (volume 2) were (1) magnitudes of monthly and annual flows; (2) duration of daily mean flows; and (3) maximum, median, and minimum daily mean flows.

Idaho↗
USGS2002

Assessment of stream quality using biological indices at selected sites in the Schuylkill River basin, Chester County, Pennsylvania, 1981-97

Introduction In 1970, the Chester County Water Resources Authority (Pennsylvania) and the U.S. Geological Survey (USGS) established a long-term water-quality network with the goal of assessing the quality of streams in the county and understanding stream changes in response to urbanization using benthic-macroinvertebrate data. This database represents one of the longest continuous water-quality data sets in the country. Benthic macroinvertebrates are aquatic insects, such as mayflies, caddisflies, riffle beetles, and midges, and other invertebrates that live on the stream bottom. Benthic macroinvertebrates are useful in evaluating stream quality because their habitat preferences and low motility cause them to be affected directly by substances that enter the aquatic system. By evaluating the diversity and community structure of benthic-macroinvertebrate populations, a determination of stream quality can be made. Between 1981 and 1997, the network consisted of 43 sites in 5 major basins in Chester County—Delaware, Schuylkill, Brandywine, Big Elk and Octoraro, and Red and White Clay. Benthic-macroinvertebrate, water-chemistry, and habitat data were collected each year in October or November during base-flow conditions. Using these data, Reif evaluated the overall water-quality condition of Chester County streams. This Fact Sheet summarizes the key findings from Reif for streams in the Schuylkill River Basin. These streams include Pigeon Creek (site 10), Stony Run (site 6), French Creek (sites 12-16), Pickering Creek (sites 1-5), Little Valley Creek (site 49), and Valley Creek (site 50). This summary includes an analysis of stream conditions based on benthic-macroinvertebrate samples and an analysis of trends in stream conditions for the 17-year study period.

Fact Sheet↗
USGS2016

Temporal trends and stationarity in annual peak flow and peak-flow timing for selected long-term streamflow-gaging stations in or near Montana through water year 2011: Chapter B in Montana StreamStats

A large-scale study by the U.S. Geological Survey, in cooperation with the Montana Department of Transportation and the Montana Department of Natural Resources and Conservation, was done to investigate general patterns in peak-flow temporal trends and stationarity through water year 2011 for 24 long-term streamflow-gaging stations (hereinafter referred to as gaging stations) in Montana. Hereinafter, all years refer to water years; a water year is the 12-month period from October 1 through September 30 and is designated by the year in which it ends. The primary focus of the study was to identify general patterns in peak-flow temporal trends and stationarity that are relevant to application of peak-flow frequency analyses within a statewide gaging-station network. Temporal trends were analyzed for two hydrologic variables: annual peak flow and peak-flow timing. Annual peak flow is the maximum instantaneous discharge, in cubic feet per second, recorded each year a gaging station was operated. Peak-flow timing is the day of the annual peak flow (hereinafter referred to as day of peak), recorded each year a gaging station was operated. Study results provide evidence that annual peak flow for most of the long-term gaging stations can be reasonably considered as stationary for application of peak-flow frequency analyses within a statewide gaging station network. Upward trends in annual peak flow during 1930–76 generally were stronger than downward trends during 1967–2011 for most long-term gaging stations. Statistical distributions of annual peak flow generally were similar among three summary time periods (1930–78, 1979–2011, and the entire period of record). However, for two low-elevation gaging stations in eastern Montana (Poplar River at international boundary [gaging station 06178000] and Powder River at Moorhead, Montana [gaging station 06324500]), substantial downward trends in annual peak flow during 1967–2011 were of similar or stronger magnitude than the upward trends during 1930–76, and the annual-peak-flow medians for 1979–2011 were substantially lower than the medians for the entire period of record. For peak-flow timing for most long-term gaging stations, differences in trends between 1930–76 and 1967–2011 are variable and not particularly strong. Statistical distributions generally are similar among the summary time periods. However, for two high-elevation gaging stations on a Missouri River headwater tributary (Gallatin River near Gallatin Gateway, Montana [gaging station 06043500] and Gallatin River at Logan, Montana [gaging station 06052500]) and for five high-elevation gaging stations in the Yellowstone River Basin (Yellowstone River at Corwin Springs, Montana [gaging station 06191500], Yellowstone River near Livingston, Montana [gaging station 06192500], Clarks Fork Yellowstone River near Belfry, Montana [gaging station 06207500], Clarks Fork Yellowstone River at Edgar, Montana [gaging station 06208500], and Yellowstone River at Billings, Montana [gaging station 06214500]) downward trends in peak-flow timing during 1967–2011 generally were stronger than upward trends during 1930–1976, and day-of-peak medians for 1979–2011 were considerably less than medians for 1930–78. The downward trends in peak-flow timing for 1967–2011 indicate that the timing of annual peak flows changed from later in the year to earlier in the year. For the seven high-elevation gaging stations, the mean change during 1967–2011 was about 13 days (range of 8 to 22 days). For most of the high-elevation gaging stations in the Missouri River headwaters, Yellowstone River Basin, and Columbia River Basin, there was general correspondence between trend patterns for annual peak flow and trend patterns for peak-flow timing; that is, during periods when there were upward trends in annual peak flow, there generally also were upward trends in peak-flow timing. Conversely, during periods when there were downward trends in annual peak flow, there generally also were downward trends in peak-flow timing. The two low-elevation gaging stations in eastern Montana (Poplar River at international boundary [gaging station 06178000] and Powder River at Moorhead, Montana [gaging station 06324500]) had considerable changes in annual-peakflow characteristics after the mid-1970s, which might provide evidence of potential nonstationarity in the peak-flow records. The two low-elevation gaging stations that have potential nonstationarity are located in drainage basins that are strongly affected by agricultural activities that potentially affect the hydrologic regimes. Primary agricultural activities that might alter natural hydrologic conditions include construction of small impoundments (primarily for stock-watering purposes) and irrigation diversions. Temporal variability in these activities might contribute to the potential nonstationarity issues. Changes in climatic characteristics after the mid-1970s also possibly contribute to the potential nonstationarity issues. Lack of considerable indication of potential nonstationarity in annual peak flow for the other long-term gaging stations in this study might indicate that climatic changes have been more pronounced with respect to effects on peak flows in low elevation areas in eastern Montana than in areas represented by the other long-term gaging stations. Another possibility is that climatic changes after the mid-1970s are exacerbated in low-elevation areas where small-impoundment development and potential effects of irrigation diversions might be more extensive.

Montana↗
USGS1988

Streamflow characteristics of the Green, Bear, and Snake River basins, Wyoming, through 1984

A summary of streamflow characteristics as of 1984 is presented for the Green, Bear, and Snake River Basins in Wyoming and adjacent areas, based on data from 101 streamflow-gaging stations. Streamflow characteristics include mean monthly and mean annual streamflow, duration of daily mean flow, and magnitude and probability of instantaneous peak flow, annual high flow, and annual low flow. Recurrence intervals of 2, 5, 10 , 25, 50 and 100 yr are utilized for the peak-flow, high-flow and low-flow characteristics. Low-flow and high-flow characteristics are also listed for standard periods of consecutive days. A station description, tables of streamflow characteristics, and graphs of mean monthly streamflow and duration of daily mean streamflow are presented for each station. Streamflow characteristics before and after dam construction are presented for five stations. (USGS)

Water-Resources Investigations Report↗
USGS1988

Statistical summaries of streamflow records in Oklahoma and parts of Arkansas, Missouri, and Texas through 1984

Statistical summaries of streamflow records through 1984 for gaging stations in Oklahoma and parts of adjacent states are presented in this report. Records are presented for 148 stations with at least 10 years of unregulated or regulated streamflow. Streamflow at 70 of the stations is regulated for certain perdiods. Data for these periods were analyzed separately to account for changes in streamflow due to regulating structures. For each gaging station, a brief description of the location, drainage area and period of record is given. For those stations with a regulated streamflow record, a brief regulation history is given also. This information is followed by tables of monthly and annual discharge statistics, low- and high-flow frequency statistics, peak-flow frequency statistics, and flow-duration statistics. Daily flow-duration hydrographs are included for most stations.

Arkansas, Missouri, Oklahoma, Texas↗
USGS1980

Outer continental shelf oil and gas activities in the Pacific (Southern California) and their onshore impacts: a summary report, May 1980

Outer Continental Shelf (OCS) oil and gas exploration and development have been under way in the Pacific (Southern California) Region since 1966. During that time, there have been four Federal lease sales: in 1966, 1968, 1975 (Sale 35), and 1979 (Sale 48). Oil and gas production from three leases has been going on since 1968. It peaked in 1971 and now averages around 31,400 barrels of oil and 15.4 million cubic feet of gas per day. Discoveries on areas leased in the 1968 and 1975 sales have led to plans for eight new platforms to begin production in the early 1980's. Five platforms are in the eastern end of Santa Barbara Channel, one is in the western Channel, and two are in San Pedro Bay, south of Long Beach. Three rigs are doing exploratory drilling in the Region. The most recent estimates by the U.S. Geological Survey of remaining reserves for all identified fields in the Southern California Region are 695 million barrels of oil and 1,575 billion cubic feet of gas (January 1979). The USGS has also made risked estimates of economically recoverable oil and gas resources for all the leased tracts in the Region (March 1980). These risked estimates of economically recoverable resources are 394 billion barrels of oil and 1,295 billion cubic feet of gas. The USGS estimates of undiscovered recoverable resources for the entire Southern California OCS Region (January 1980) are 3,200 million barrels of oil and 3,400 billion cubic feet of gas. Because of the long history of oil and gas production in Southern California from wells onshore and in State waters, there are many existing facilities for the transportation, processing, and refining of oil and gas. Some of the expected new OCS production can be accommodated in these facilities. Four new onshore projects will be required. Two of these are under construction: (1) a 9.6-km (6-mi) onshore oil pipeline (capacity: 60,000 bpd) between Carpinteria (Santa Barbara County) and the existing Mobil-Rincon separation and treatment facility (Ventura County), and (2) a small supply base and dock (upgrade of existing facility) and a 0.4-hectare (1-acre) crude oil distribution facility in Long Beach (Los Angeles County), connected to landfall by a 3-km (1.8-mi) onshore pipeline. The two other facilities are awaiting permit approval: (1) a gas treatment plant at Las Flores Canyon (Santa Barbara County) and (2) a separation and treatment plant at Mandalay Beach (Ventura County) with 4 km (2.5 mi) of onshore pipeline on the same right-of-way from landfall to the plant and from the plant to an existing gas transmission line.

California↗
USGS2002

Assessment of stream quality using biological indices at selected sites in the Big Elk and Octoraro Creek basins, Chester County, Pennsylvania, 1981-97

Introduction In 1970, the Chester County Water Resources Authority (Pennsylvania) and the U.S. Geological Survey (USGS) established a long-term water-quality network with the goal of assessing the quality of streams in the county and understanding stream changes in response to urbanization using benthic-macroinvertebrate data. This database represents one of the longest continuous water-quality data sets in the country. Benthic macroinvertebrates are aquatic insects, such as mayflies, caddisflies, riffle beetles, and midges, and other invertebrates that live on the stream bottom. Benthic macroin-vertebrates are useful in evaluating stream quality because their habitat preference and low motility cause them to be affected directly by substances that enter the aquatic system. By evaluating the diversity and community structure of benthic-macroinvertebrate populations, a determination of stream quality can be made. Between 1981 and 1997, the water-quality network consisted of 43 sites in 5 major basins in Chester County—Delaware, Schuylkill, Brandywine, Big Elk and Octoraro, and Red and White Clay. Benthic-macroinvertebrate, water-chemistry, and habitat data were collected each year in October or November during base-flow conditions. Using these data, Reif evaluates the overall water-quality condition of Chester County streams. This Fact Sheet summarizes the key findings from Reif for streams in the Big Elk and Octoraro Creek Basins. These streams include East Branch Big Elk Creek (site 31), West Branch Big Elk Creek (site 32), East Branch Octoraro Creek (site 33) and Valley Creek (site 34). This summary includes an analysis of stream conditions based on benthic-macroinvertebrate samples and an analysis of trends in stream conditions for the 17-year study period.

Fact Sheet↗
USGS2002

Assessment of stream quality using biological indices at selected sites in the Delaware River basin, Chester County, Pennsylvania, 1981-97

Introduction In 1970, the Chester County Water Resources Authority (Penn-sylvania) and the U.S. Geological Survey (USGS) established a long-term water-quality network with the goal of assessing the quality of streams in the county and understanding stream changes in response to urbanization using benthic-macroinvertebrate data. This database represents one of the longest continuous water-quality data sets in the country. Benthic macroinvertebrates are aquatic insects, such as mayflies, caddisflies, riffle beetles, and midges, and other invertebrates that live on the stream bottom. Benthic macroinvertebrates are useful in evaluating stream quality because their habitat preferences and low motility cause them to be affected directly by substances that enter the aquatic system. By evaluating the diversity and community structure of benthic-macroinvertebrate populations, a determination of stream quality can be made. Between 1981 and 1997, the water-quality network consisted of 43 sites in 5 major basins in Chester County—Delaware, Schuylkill, Brandywine, Big Elk and Octoraro, and Red and White Clay. Benthic-macroinvertebrate, water-chemistry, and habitat data were collected each year in October or November during base-flow condition. Using these data, Reif evaluates the overall water-quality condition of Chester County streams. This Fact Sheet summarizes the key findings from Reif for streams in the Delaware River Basin. These streams include Darby Creek (site 17), Crum Creek (site 19), Ridley Creek (sites 20 and 21), East Branch Chester Creek (sites 22-24, and 51), and Goose Creek (site 25). This summary includes an analysis of stream conditions on the basis of benthic-macroinvertebrate samples and an analysis of trends in stream conditions for the 17-year study period.

Fact Sheet↗
USGS2006

Response to memorandum by Rowley and Dixon regarding U.S. Geological Survey report titled "Characterization of Surface-Water Resources in the Great Basin National Park Area and Their Susceptibility to Ground-Water Withdrawals in Adjacent Valleys, White Pine County, Nevada"

Applications pending for permanent permits to pump large quantities of ground water in Spring and Snake Valleys adjacent to Great Basin National Park (the Park) prompted the National Park Service to request a study by the U.S. Geological Survey to evaluate the susceptibility of the Park's surface-water resources to pumping. The result of this study was published as U.S. Geological Survey Scientific Investigations Report 2006-5099 'Characterization of Surface-Water Resources in the Great Basin National Park Area and Their Susceptibility to Ground-Water Withdrawals in Adjacent Valleys, White Pine County, Nevada,' by P.E. Elliott, D.A. Beck, and D.E. Prudic. That report identified areas within the Park where surface-water resources are susceptible to ground-water pumping; results from the study showed that three streams and several springs near the eastern edge of the Park were susceptible. However, most of the Park's surface-water resources likely would not be affected by pumping because of either low-permeability rocks or because ground water is sufficiently deep as to not be directly in contact with the streambeds. A memorandum sent by Peter D. Rowley and Gary L. Dixon, Consulting Geologists, to the Southern Nevada Water Authority (SNWA) on June 29, 2006 was critical of the report. The memorandum by Rowley and Dixon was made available to the National Park Service, the U.S. Geological Survey, and the public during the Nevada State Engineer's 'Evidentiary Exchange' process for the recent hearing on applications for ground-water permits by SNWA in Spring Valley adjacent to Great Basin National Park. The U.S. Geological Survey was asked by the National Park Service to assess the validity of the concerns and comments contained in the Rowley and Dixon memorandum. An Administrative Letter Report responding to Rowley and Dixon's concerns and comments was released to the National Park Service on October 30, 2006. The National Park Service subsequently requested that the contents with three minor changes to the Administrative Letter Report be released to the public. The first paragraph was revised to better explain how the memorandum was brought to the attention of the National Park Service and the U.S. Geological Survey and the purpose of the Administrative Letter Report. The second and third changes were minor word changes to the end of the first sentence at the top of page 11 and in the Summary statement, respectively. The Administrative Letter Report with these minor changes is reproduced herein. Lastly, the National Park Service asked me to explain the difference between potentially and likely susceptible areas used in the report. Admittedly, the report did not clearly explain their usage. Potentially susceptible areas were used in the report to identify areas where (1) ground water interacts with water in the creeks but the connection between permeable rocks in the mountains with the basin fill is uncertain or where (2) ground-water interaction with water in the creeks is less certain but permeable rocks are connected with basin fill. Likely susceptible areas were used to identify areas in the mountains and valleys where ground-water interacts with water in the creeks or discharges as springs and permeable rocks are connected with basin fill. Likely susceptible areas are, therefore, more vulnerable to ground-water pumping.

Open-File Report↗
USGS2003

Ground-water-quality assessment of shallow aquifers in the Front Range Urban Corridor, Colorado, 1954-98

Historical (1954­98) water-quality data for major ions, trace elements, major plant nutrients, and organic constituents collected in 3,870 sampling events at 2,138 shallow wells represent ground-water quality in shallow aquifers that underlie the Front Range Urban Corridor in Colorado. Nonparametric summary statistics and maps of concentrations across the study area indicate that ground water in the study area included fresh to saline water. Sulfate concentrations were elevated in the north and northeast parts of the study area, possibly due to Pierre Shale and Laramie Formation shale outcrops in those areas. Apart from isolated areas of known contamination, chloride concentrations were generally less than 100 milligrams per liter across the study area. Wells with elevated nitrate concentrations usually were located near rivers and streams downgradient from metropolitan areas. Elevated nitrate concentrations in wells that were not along the South Platte River were possibly from individual sewage disposal system usage or from fertilizer application to land. Spatial distribution for organic compounds for which more than 40 percent of the data were above the detection limit (atrazine, methyl-tert-butylether, and prometon) is not widespread across the study area, but this may reflect limitations of data availability. Summary statistics calculated or estimated by decade are influenced by the temporal variability of data across the study area. The median values of specific conductance, chloride, and nitrate from the 1970’s are less than values from the 1980’s and 1990’s, which, because most samples from the l970’s were collected in the western part of the study area, indicates that water quality in the western part of the study area is generally different than the rest of the study area. Chloride may be introduced to ground water from runoff of road deicers or chlorinated organics in transportation/transitional areas, where the median concentration is the greatest (85.0 milligrams per liter). Nitrate median concentrations are several times greater where the land is cultivated or used for agricultural business, which may reflect use of nitrogen fertilizers and the presence of animal feeding operations. Most inorganic and organic constituents exceeded drinking-water standards in only a small percentage of samples. Exceptions to this include sulfate; nitrate; trace elements aluminum, cadmium, iron, and manganese; and organic compounds 1,1-dichloroethylene, tetrachloroethylene, trichloroethylene, benzene, and dichloromethane.

Colorado↗
USGS2013

U.S. Geological Survey core science systems strategy: Characterizing, synthesizing, and understanding the critical zone through a modular science framework

Executive Summary Core Science Systems is a new mission of the U.S. Geological Survey (USGS) that resulted from the 2007 Science Strategy, “Facing Tomorrow’s Challenges: U.S. Geological Survey Science in the Decade 2007–2017.” This report describes the Core Science Systems vision and outlines a strategy to facilitate integrated characterization and understanding of the complex Earth system. The vision and suggested actions are bold and far-reaching, describing a conceptual model and framework to enhance the ability of the USGS to bring its core strengths to bear on pressing societal problems through data integration and scientific synthesis across the breadth of science. The context of this report is inspired by a direction set forth in the 2007 Science Strategy. Specifically, ecosystem-based approaches provide the underpinnings for essentially all science themes that define the USGS. Every point on Earth falls within a specific ecosystem where data, other information assets, and the expertise of USGS and its many partners can be employed to quantitatively understand how that ecosystem functions and how it responds to natural and anthropogenic disturbances. Every benefit society obtains from the planet— food, water, raw materials to build infrastructure, homes and automobiles, fuel to heat homes and cities, and many others— are derived from or affect ecosystems. The vision for Core Science Systems builds on core strengths of the USGS in characterizing and understanding complex Earth and biological systems through research, modeling, mapping, and the production of high quality data on the Nation’s natural resource infrastructure. Together, these research activities provide a foundation for ecosystem-based approaches through geologic mapping, topographic mapping, and biodiversity mapping. The vision describes a framework founded on these core mapping strengths that makes it easier for USGS scientists to discover critical information, share and publish results, and identify potential collaborations that transcend all USGS missions. The framework is designed to improve the efficiency of scientific work within USGS by establishing a means to preserve and recall data for future applications, organizing existing scientific knowledge and data to facilitate new use of older information, and establishing a future workflow that naturally integrates new data, applications, and other science products to make interdisciplinary research easier and more efficient. Given the increasing need for integrated data and interdisciplinary approaches to solve modern problems, leadership by the Core Science Systems mission will facilitate problem solving by all USGS missions in ways not formerly possible. The report lays out a strategy to achieve this vision through three goals with accompanying objectives and actions. The first goal builds on and enhances the strengths of the Core Science Systems mission in characterizing and understanding the Earth system from the geologic framework to the topographic characteristics of the land surface and biodiversity across the Nation. The second goal enhances and develops new strengths in computer and information science to make it easier for USGS scientists to discover data and models, share and publish results, and discover connections between scientific information and knowledge. The third goal brings additional focus to research and development methods to address complex issues affecting society that require integration of knowledge and new methods for synthesizing scientific information. Collectively, the report lays out a strategy to create a seamless connection between all USGS activities to accelerate and make USGS science more efficient by fully integrating disciplinary expertise within a new and evolving science paradigm for a changing world in the 21st century.

Circular↗
USGS2021

National Park Service Vegetation Mapping Inventory Program: Great Smoky Mountains National Park vegetation mapping project

The National Park Service (NPS) Vegetation Mapping Inventory (VMI) Program is an effort to classify, describe, and map existing vegetation communities in national park units throughout the United States. The NPS VMI Program is managed by the NPS Natural Resource Stewardship and Science Inventory and Monitoring Program and provides baseline vegetation information to natural resource managers, researchers, and ecologists. The U.S. Geological Survey Upper Midwest Environmental Sciences Center, NatureServe, and NPS Great Smoky Mountains National Park (GRSM, also referred to as the “Park”) have completed vegetation classification and mapping of GRSM, including the Foothills Parkway, for the NPS VMI Program. Mappers, ecologists, and botanists collaborated to affirm vegetation types of GRSM and to determine how best to map the vegetation types by using aerial imagery. A vegetation classification developed in 2003 by NatureServe and the NPS served as a foundation to further classify and map the vegetation types of the Park. Data from an additional 10 vegetation plots supported vegetation types either rare or not documented in the 2003 classification. Data from 203 verification sites were collected to test the field key to vegetation types and the application of vegetation types to a sample set of map polygons. Furthermore, data from 972 accuracy assessment (AA) sites were collected (of which 966 were used to test accuracy of the vegetation map layer). This GRSM vegetation mapping project identified 112 vegetation types consisting of 105 association types in the U.S. National Vegetation Classification (USNVC), 2 “park-special” types, 1 “map-special” type, and 4 cultural types in the USNVC. To map the vegetation and land cover of GRSM, 52 map classes were developed. Of these 52 map classes, 46 represent natural (including ruderal) vegetation types, most of which types are recognized in the USNVC. For the remaining 6 of the 52 map classes, 4 represent USNVC cultural types for agricultural and developed areas, and 2 represent non-USNVC types for nonvegetated open water and nonvegetated rock. Features were interpreted from viewing four-band digital aerial imagery using digital onscreen three-dimensional stereoscopic workflow systems in geographic information systems; digital aerial imagery was collected during September 23–October 30, 2015. The interpreted data were digitally and spatially referenced, thus making the spatial-database layers usable in a geographic information system. Polygon units were mapped to either a 0.5- or 0.25- hectare (ha) minimum mapping unit, depending on vegetation type. A geodatabase containing several feature-class layers and tables provides the locations and data of USNVC vegetation types (vegetation map layer), vegetation plots, verification sites, AA sites, project boundary extent, and aerial image centers and flight lines. Covering 210,875 ha, the feature-class layer and related tables for the vegetation map layer provide 34,084 polygons of detailed attribute data when special modifiers are not considered (average polygon size of 6.2 ha) and 36,589 polygons of detailed attribute data when special modifiers are considered (average polygon size of 5.8 ha). Each map polygon is assigned a map-class code and name and, when applicable, are linked to USNVC classification tables within the geodatabase. The vegetation map extent includes the administrative boundary for GRSM and the Foothills Parkway. A summary report, generated from the vegetation map layer, concludes that the 46 map classes representing natural (including ruderal) vegetation types apply to 99.2% of polygons (33,797 polygons; average size of 6.2 ha) and cover 98.6% of the Park (207,971.4 ha). Further broken down, map classes representing natural vegetation types indicate that the Park is 97.7% forest and woodland (205,882.5 ha), 0.6% shrubland (1,174.6 ha), and 0.4% herbaceous (914.3 ha). Map classes representing cultural vegetation types apply to 0.8% of polygons (259 polygons; average size of 4.9 ha) and cover 0.6% of the Park (1,277.4 ha). Map classes representing nonvegetation open and flowing water and unvegetated rock apply to 0.08% of polygons (28 polygons; average size of 58.1 ha) and cover 0.8% of the Park (1,625.9 ha). A thematic AA study was completed of map classes representing the natural (including ruderal) vegetation types of the Park. Initial AA results were discussed with NPS staff from the Park. Following input from NPS staff on how to handle map classes that fell below accuracy standards, adjustments were made to the vegetation map layer. Final results indicate an overall accuracy of 80.64% (kappa index of 79.96% for chance agreements) based on data from 966 of the 972 AA sites. Most individual map-class themes exceed the NPS VMI Program standard of 80% with a 90% confidence interval. The GRSM vegetation mapping project delivers many geospatial and vegetation data products, including an in-depth project report discussing methods and results, which includes map classification and map-class descriptions. This suite of products also includes descriptions and a field key to vegetation types; a database of vegetation plots, verification sites, and AA sites; digital images of field sites; field data sheets; digital aerial imagery; hardcopy and digital maps; a geodatabase of vegetation and land cover (map layer), field sites (vegetation plots, verification sites, and AA sites), aerial imagery index, project boundary, and metadata; and a contingency table listing AA results. Geospatial products are projected in the Universal Transverse Mercator, Zone 17 North, by using the North American Datum of 1983. Information on the NPS VMI Program and completed mapping projects are on the internet at https://www.nps.gov/im/vegetation-inventory.htm.

North Carolina, Tennessee↗
USGS2002

Assessment of stream quality using biological indices at selected sites in the Brandywine Creek basin, Chester County, Pennsylvania, 1981-97

In 1970, the Chester County Water Resources Authority (Pennsylvania) and the U.S. Geological Survey (USGS) established a longterm water-quality network with the goal of assessing the quality of streams in the county and understanding stream changes in response to urbanization using benthic-macroinvertebrate data. This database represents one of the longest continuous water-quality data sets in the country. Benthic macroinvertebrates are aquatic insects, such as mayflies, caddisflies, riffle beetles, and midges, and other invertebrates that live on the stream bottom. Benthic macroinvertebrates are useful in evaluating stream quality because their habitat preferences and low motility cause them to be affected directly by substances that enter the aquatic system. By evaluating the diversity and community structure of benthic-macroinvertebrate populations, a determination of stream quality can be made. Between 1981 and 1997, the water-quality network consisted of 43 sites in 5 major basins in Chester County—Delaware, Schuylkill, Brandywine, Big Elk and Octoraro, and Red and White Clay. Benthicmacroinvertebrate, water-chemistry, and habitat data were collected each year in October or November during base-flow conditions. Using these data, Reif evaluated the overall water-quality condition of Chester County streams. This Fact Sheet summarizes the key findings from Reif for streams in the Brandywine Creek Basin. These streams include West Branch Brandywine Creek (sites 37 and 38), Buck Run (site 46), Doe Run (site 45), East Branch Brandywine Creek (sites 48, 42, 36, and 39), Indian Run (site 47), West Valley Creek (site 44), and Main Stem Brandywine Creek (site 40). This summary includes an analysis of stream conditions based on benthic-macroinvertebrate samples and an analysis of trends in stream conditions for the 17-year study period.

Fact Sheet↗
USGS1997

National Geochemical Database: Reformatted data from the National Uranium Resource Evaluation (NURE) Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) program

The National Uranium Resource Evaluation (NURE) Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) program produced a large amount of geochemical data. To fully understand how these data were generated, it is recommended that you read the History of NURE HSSR Program for a summary of the entire program. By the time the NURE program had ended, the HSSR data consisted of 894 separate data files stored with 47 different formats. Many files contained duplication of data found in other files. The University of Oklahoma's Information Systems Programs of the Energy Resources Institute (ISP) was contracted by the Department of Energy to enhance the accessibility and usefulness of the NURE HSSR data. ISP created a single standard-format master file to replace the 894 original files. ISP converted 817 of the 894 original files before its funding apparently ran out. The ISP-reformatted NURE data files have been released by the USGS on CD-ROM (Lower 48 States, Hoffman and Buttleman, 1994; Alaska, Hoffman and Buttleman, 1996). A description of each NURE database field, derived from a draft NURE HSSR data format manual (unpubl. commun., Stan Moll, ISP, Oct 7, 1988), was included in a readme file on each CD-ROM. That original manual was incomplete and assumed that the reformatting process had gone to completion. A lot of vital information was not included. Efforts to correct that manual and the NURE data revealed a large number of problems and missing data. As a result of the frustrating process of cleaning and re-cleaning data from the ISP-reformatted NURE files, a new NURE HSSR data format was developed. This work represents a totally new attempt to reformat the original NURE files into 2 consistent database structures; one for water samples and a second for sediment samples, on a quadrangle by quadrangle basis, from the original NURE files. Although this USGS-reformatted NURE HSSR data format is different than that created by the ISP, many of their ideas were incorporated and expanded in this effort. All of the data from each quadrangle are being examined thoroughly in an attempt to eliminate problems, to combine partial or duplicate records, to convert all coding to a common scheme, and to identify problems even if they can not be solved at this time.

Open-File Report↗
USGS2002

Assessment of stream quality using biological indices at selected sites in the Red Clay and White Clay Creek basins, Chester County, Pennsylvania, 1981-97

In 1970, the Chester County Water Resources Authority (Pennsylvania) and the U.S. Geological Survey (USGS) established a long-term water-quality network with the goal of assessing the quality of streams in the county and understanding stream changes in response to urbanization using benthic-macroinvertebrate data. This database represents one of the longest continuous water-quality data sets in the country. Benthic macroinvertebrates are aquatic insects, such as mayflies, caddisflies, riffle beetles, and midges, and other invertebrates that live on the stream bottom. Benthic macroinvertebrates are useful in evaluating stream quality because their habitat preference and low motility cause them to be affected directly by substances that enter the aquatic system. By evaluating the diversity and community structure of benthic-macroinvertebrate populations, a determination of stream quality can be made. Between 1981 and 1997, the water-quality network consisted of 43 sites in 5 major basins in Chester County—Delaware, Schuylkill, Brandywine, Big Elk and Octoraro, and Red and White Clay. Benthicmacroinvertebrate, water-chemistry, and habitat data were collected each year in October or November during base-flow conditions. Using these data, Reif evaluates the overall water-quality condition of Chester County streams. This Fact Sheet summarizes the key findings from Reif for streams in the Red Clay and White Clay Creek Basins. These streams include East Branch Red Clay Creek (site 26), West Branch Red Clay Creek (site 27), East Branch White Clay Creek (site 28), the Middle Branch White Clay Creek (site 29), and West Branch White Clay Creek (site 30). This summary includes an analysis of stream conditions on the basis of benthic-macroinvertebrate samples and an analysis of trends in stream conditions for the 17-year study period.

Pennsylvania↗
USGS1985

Summary of northern Atlantic Coastal Plain hydrology and its relation to disposal of high-level radioactive waste in buried crystalline rock – A preliminary appraisal

Interpretation of available hydrologic data suggests that some areas beneath the Coastal Plain in the States of Delaware, Maryland, New Jersey, North Carolina, and Virginia might have some potential for the disposal of nuclear waste in crystalline rock that is buried beneath the Coastal Plain sediments. The areas of major interest occur where the top of the basement rock lies between 1,000 and 4,000 feet below sea level, the aquifer(s) immediately above the basement rock are saturated with saline water, confining material overlies the saline water bearing aquifer(s), and groundwater flow in the saline water aquifer(s) can be established. Preliminary data on (1) the distribution and thickness of the lowermost aquifers and confining beds, (2) the distribution of hydraulic conductivity in the lowermost aquifers, (3) estimated hydraulic heads and inferred direction of lateral groundwater flow for 1980, and (4) the distribution of saline water and brine, indicate eastern parts of the study area relatively best meet most of the criteria proposed for sediments that would overlie any potential buried crystalline-rock disposal site.

Delaware, Maryland, New Jersey, North Carolina, Vi↗
USGS1982

Gulf of Mexico summary report 3 August 1982: A revision of Outer Continental Shelf oil and gas activities in the Gulf of Mexico and their onshore impacts: Gulf of Mexico summary report 2, August 1981

Now, and for the near future, the Gulf of Mexico will remain the most developed Outer Continental Shelf (OCS) region in the United States and the world. Virtually all production from the U.S. OCS emanates from the Gulf of Mexico. In calendar year 1981, for the two primary categories of hydrocarbons produced from the OCS, oil/condensate and gas, Gulf production accounted for over 94 and 99 percent, respectively. Oil production for 1981 was 0.27 billion barrels, and gas production was 4.84 trillion cubic feet. Although most of the shallow-water areas of the Gulf of Mexico Continental Shelf have been explored, considerable amounts of hydrocarbons may yet be discovered in deepwater locations. Industry has been developing the technology to explore deepwater areas, and interest in these portions of the Gulf is increasing. As of December 1981, the total of all identified oil and gas fields in the Gulf of Mexico OCS increased to 505 from 482 at the end of the previous year; this net increase of 23 fields discovered in 1981 compares to net increases of 50 in 1980, 51 in 1979, and 25 in 1978. The number of active fields increased from 466 in 1981, and fields for which reserve estimates have been made increased from 419 to 445. As of January 1982, 19,736 offshore oil and gas wells had been drilled in the Gulf of Mexico OCS; most of the wells (17,257) are off the coast of Louisiana. Currently, there are 2,027 active oil and gas leases in the Gulf of Mexico; 1,200 of them are producing leases. The Department of the Interior's 5-year OCS oil and gas leasing schedule projects 2 to 3 Gulf of Mexico lease sales per year through 1987, for a total of 12 offerings, and starting in 1983, the Gulf will be divided into three planning areas. Resource estimates issued for the following Gulf of Mexico lease sales are as follows: Lease Sale 67--75.16 million barrels of oil and 1.03 trillion cubic feet of gas; Lease Sale 69--48.24 million barrels of oil and .785 trillion cubic feet of gas; Lease Sale 72--97 million barrels of oil and 1.04 trillion cubic feet of gas; Lease Sale 74--29 million barrels of oil and .525 trillion cubic feet of gas; and Lease Sale 79--123 million barrels of oil and .157 trillion cubic feet of gas. Since 1972, oil production in the Gulf of Mexico has declined each year, and gas production, thought to have reached its peak in 1981, is also expected to begin a noticeable decline. To date, most of the oil and gas discovered in the Gulf has occurred on the Texas-Louisiana Shelf, but in the future, oil and gas exploration is likely to include a number of areas where previous leasing has not been extensive. The West Florida Shelf, especially the area off the coast of southwest Florida and the deepwater areas southeast of the Mississippi River Delta, are potential areas for future exploration. As production begins to decline from mature fields, smaller fields will become economically producible, and implementation of secondary and tertiary recovery techniques will make it possible to extract more oil and gas from reservoirs than was possible previously. Each year, hundreds of miles of pipelines are added to the existing network in the Gulf of Mexico. Recently, there have been a number of proposals for deepwater ports and transshipment terminals as well as projects including the deepening or widening of existing conventional ports. The process of transportation planning in the Gulf of Mexico is done by industry and government through the Intergovernmental Planning Program and its Regional Technical Working Group. The Gulf Coast region is an area of significant onshore oil and gas activity, with many cities and towns offering a wide range of services and supplies to onshore and offshore oil operators and their ancillary industries. While the western and central Gulf oil and gas support infrastructure is quite extensive and complex, the support facilities in the eastern Gulf are still in the early stages of development. In the likely event of a decline in Gulf OCS production, imported oil may be substituted for dwindling domestic stocks at Gulf Coast refineries. Planners must consider impacts generated by changes in oil and gas productivity and focus on finding alternative uses for facilities and alternative employment for workers.

Alabama, Florida, Louisiana, Mississippi, Texas↗
USGS1986

Summary of hydrologic conditions in the Reedy Creek Improvement District, central Florida

The Reedy Creek Improvement is an area of about 43 square miles in southwestern Orange and northwestern Osceola Counties, Florida. A systematic program of hydrologic data collection in the Reedy Creek Improvement District and vicinity provided data for assessing the impact of development, mostly the Walt Disney World Theme Park and related development on the hydrology. Data collected include stream discharge, water quality, groundwater levels, lakes levels, and climatological. Rainfall has been less than the long-term average in the Reedy Creek Improvement District since development began in 1968. The deficient rainfall has reduced stream discharge, lowered groundwater and lake levels, and possibly affected water quality in the area. Groundwater levels and lake levels have declined since 1970. However, the coincidence of below-average rainfall with the period of development makes it impossible to assess the effect of pumping on declines. Occurrence of toxic metals does not relate to development, but distribution of insecticides and herbicides does appear to relate to development. Specific conductance, phosphorous, and nitrate concentrations have increased in Reedy Creek since 1970, probably due to disposal of treated wastes. (USGS)

Water-Resources Investigations Report↗