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At least 1,279 records · Page 71Linked to original sources
USGS1997

Geology and mineral resource assessment of the Venezuelan Guayana Shield at 1:500,000 scale; a digital representation of maps published by the U.S. Geological Survey

This CD-ROM contains vector-based digital maps of the geology and resource assessment of the Venezuela Guayana Shield originally published as paper maps in 1993 in U. S. Geological Survey Bulletin 2062, at a scale of 1:1 million and revised in 1993-95 as separate maps at a scale of 1:500,000. Although the maps on this disc can be displayed at different scales, they are not intended to be used at any scale more detailed than 1:500,000.

Data Series↗
USGS2009

Probability of Unmixed Young Groundwater (defined using chlorofluorocarbon-11 concentrations and tritium activities) in the Eagle River Watershed Valley-Fill Aquifer, Eagle County, North-Central Colorado, 2006-2007

This raster data set delineates the predicted probability of unmixed young groundwater (defined using chlorofluorocarbon-11 concentrations and tritium activities) in groundwater in the Eagle River watershed valley-fill aquifer, Eagle County, North-Central Colorado, 2006-2007. This data set was developed by a cooperative project between the U.S. Geological Survey, Eagle County, the Eagle River Water and Sanitation District, the Town of Eagle, the Town of Gypsum, and the Upper Eagle Regional Water Authority. This project was designed to evaluate potential land-development effects on groundwater and surface-water resources so that informed land-use and water management decisions can be made. This groundwater probability map and its associated probability maps were developed as follows: (1) A point data set of wells with groundwater quality and groundwater age data was overlaid with thematic layers of anthropogenic (related to human activities) and hydrogeologic data by using a geographic information system to assign each well values for depth to groundwater, distance to major streams and canals, distance to gypsum beds, precipitation, soils, and well depth. These data then were downloaded to a statistical software package for analysis by logistic regression. (2) Statistical models predicting the probability of elevated nitrate concentrations, the probability of unmixed young water (using chlorofluorocarbon-11 concentrations and tritium activities), and the probability of elevated volatile organic compound concentrations were developed using logistic regression techniques. (3) The statistical models were entered into a GIS and the probability map was constructed.

Data Series↗
USGS2009

Probability of Elevated Volatile Organic Compound (VOC) Concentrations in Groundwater in the Eagle River Watershed Valley-Fill Aquifer, Eagle County, North-Central Colorado, 2006-2007

This raster data set delineates the predicted probability of elevated volatile organic compound (VOC) concentrations in groundwater in the Eagle River watershed valley-fill aquifer, Eagle County, North-Central Colorado, 2006-2007. This data set was developed by a cooperative project between the U.S. Geological Survey, Eagle County, the Eagle River Water and Sanitation District, the Town of Eagle, the Town of Gypsum, and the Upper Eagle Regional Water Authority. This project was designed to evaluate potential land-development effects on groundwater and surface-water resources so that informed land-use and water management decisions can be made. This groundwater probability map and its associated probability maps was developed as follows: (1) A point data set of wells with groundwater quality and groundwater age data was overlaid with thematic layers of anthropogenic (related to human activities) and hydrogeologic data by using a geographic information system to assign each well values for depth to groundwater, distance to major streams and canals, distance to gypsum beds, precipitation, soils, and well depth. These data then were downloaded to a statistical software package for analysis by logistic regression. (2) Statistical models predicting the probability of elevated nitrate concentrations, the probability of unmixed young water (using chlorofluorocarbon-11 concentrations and tritium activities), and the probability of elevated volatile organic compound concentrations were developed using logistic regression techniques. (3) The statistical models were entered into a GIS and the probability map was constructed.

Data Series↗
USGS2009

Comparison of 2006-2007 Water Years and Historical Water-Quality Data, Upper Gunnison River Basin, Colorado

Population growth and changes in land use have the potential to affect water quality and quantity in the upper Gunnison River basin. In 1995, the U.S. Geological Survey (USGS), in cooperation with the Bureau of Land Management, City of Gunnison, Colorado River Water Conservation District, Crested Butte South Metropolitan District, Gunnison County, Hinsdale County, Mount Crested Butte Water and Sanitation District, National Park Service, Town of Crested Butte, Upper Gunnison River Water Conservancy District, and Western State College established a water-quality monitoring program in the upper Gunnison River basin to characterize current water-quality conditions and to assess the effects of increased urban development and other land-use changes on water quality. The monitoring network has evolved into two groups of stations - stations that are considered long term and stations that are considered rotational. The long-term stations are monitored to assist in defining temporal changes in water quality (how conditions may change over time). The rotational stations are monitored to assist in the spatial definition of water-quality conditions (how conditions differ throughout the basin) and to address local and short-term concerns. Some stations in the rotational group were changed beginning in water year 2007. Annual summaries of the water-quality data from the monitoring network provide a point of reference for discussions regarding water-quality monitoring in the upper Gunnison River basin. This summary includes data collected during water years 2006 and 2007. The introduction provides a map of the sampling sites, definitions of terms, and a one-page summary of selected water-quality conditions at the network stations. The remainder of the summary is organized around the data collected at individual stations. Data collected during water years 2006 and 2007 are compared to historical data, State water-quality standards, and Federal water-quality guidelines. Data were collected following USGS protocols (U.S. Geological Survey, variously dated).

Data Series↗
USGS2010

ATM Coastal Topography-Louisiana, 2001: UTM Zone 15 (Part 1 of 2)

These remotely sensed, geographically referenced elevation measurements of lidar-derived first-surface (FS) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of a portion of the Louisiana coastline beach face within UTM Zone 15, from Isles Dernieres to Grand Isle, acquired September 7 and 10, 2001. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative scanning lidar instrument originally developed by NASA, and known as the Airborne Topographic Mapper (ATM), was used during data acquisition. The ATM system is a scanning lidar system that measures high-resolution topography of the land surface and incorporates a green-wavelength laser operating at pulse rates of 2 to 10 kilohertz. Measurements from the laser-ranging device are coupled with data acquired from inertial navigation system (INS) attitude sensors and differentially corrected global positioning system (GPS) receivers to measure topography of the surface at accuracies of +/-15 centimeters. The nominal ATM platform is a Twin Otter or P-3 Orion aircraft, but the instrument may be deployed on a range of light aircraft. Elevation measurements were collected over the survey area using the ATM system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of lidar data in an interactive or batch mode. Modules for presurvey flight-line definition, flight-path plotting, lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or first-surface topography.

Louisiana↗
USGS2009

ATM Coastal Topography - Louisiana, 2001: UTM Zone 16 (Part 2 of 2)

These remotely sensed, geographically referenced elevation measurements of lidar-derived first-surface (FS) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of a portion of the Louisiana coastline beach face within UTM Zone 16, from Grand Isle to the Chandeleur Islands, acquired September 7 and 9, 2001. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative scanning lidar instrument originally developed by NASA, and known as the Airborne Topographic Mapper (ATM), was used during data acquisition. The ATM system is a scanning lidar system that measures high-resolution topography of the land surface and incorporates a green-wavelength laser operating at pulse rates of 2 to 10 kilohertz. Measurements from the laser-ranging device are coupled with data acquired from inertial navigation system (INS) attitude sensors and differentially corrected global positioning system (GPS) receivers to measure topography of the surface at accuracies of +/-15 centimeters. The nominal ATM platform is a Twin Otter or P-3 Orion aircraft, but the instrument may be deployed on a range of light aircraft. Elevation measurements were collected over the survey area using the ATM system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of lidar data in an interactive or batch mode. Modules for presurvey flight-line definition, flight-path plotting, lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or first-surface topography.

Louisiana↗
USGS2009

Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2008

Between January 1 and December 31, 2008, the Alaska Volcano Observatory (AVO) located 7,097 earthquakes of which 5,318 occurred within 20 kilometers of the 33 volcanoes monitored by the AVO. Monitoring highlights in 2008 include the eruptions of Okmok Caldera, and Kasatochi Volcano, as well as increased unrest at Mount Veniaminof and Redoubt Volcano. This catalog includes descriptions of: (1) locations of seismic instrumentation deployed during 2008; (2) earthquake detection, recording, analysis, and data archival systems; (3) seismic velocity models used for earthquake locations; (4) a summary of earthquakes located in 2008; and (5) an accompanying UNIX tar-file with a summary of earthquake origin times, hypocenters, magnitudes, phase arrival times, location quality statistics, daily station usage statistics, and all files used to determine the earthquake locations in 2008.

Alaska↗
USGS1998

National geochemical data base; PLUTO geochemical data base for the United States

The PLUTO CD-ROM data base contains inorganic geothermal data obtained by the analytical laboratories of the Geologic Division of the U.S. Geological Survey (USGS) for the United States, including Hawaii and Alaska, in support of USGS program activities requiring chemical data. This CD-ROM was produced in accordance with the ISO 9660 standard and can be accessed by any computer system that has the appropriate software to read the ISO 9660 discs; however, the disc is intended for use in a DOS environment.

Data Series↗
USGS2009

Summary of Seepage Investigations in the Yakima River Basin, Washington

Discharge data collected by the U.S. Geological Survey, Washington State Department of Ecology, and Yakama Nation for seepage investigations in the Yakima River basin are made available as downloadable Microsoft Excel files. These data were collected for more than a century at various times for several different studies and are now available in one location to facilitate future analysis by interested parties.

Data Series↗
USGS2010

Groundwater-quality data in the Colorado River study unit, 2007: Results from the California GAMA Program

Groundwater quality in the 188-square-mile Colorado River Study unit (COLOR) was investigated October through December 2007 as part of the Priority Basin Project of the California State Water Resources Control Board (SWRCB) Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Project was developed in response to the Groundwater Quality Monitoring Act of 2001, and the U.S. Geological Survey (USGS) is the technical project lead. The Colorado River study was designed to provide a spatially unbiased assessment of the quality of raw groundwater used for public water supplies within COLOR, and to facilitate statistically consistent comparisons of groundwater quality throughout California. Samples were collected from 28 wells in three study areas in San Bernardino, Riverside, and Imperial Counties. Twenty wells were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the Study unit; these wells are termed ‘grid wells’. Eight additional wells were selected to evaluate specific water-quality issues in the study area; these wells are termed ‘understanding wells.’ The groundwater samples were analyzed for organic constituents (volatile organic compounds [VOC], gasoline oxygenates and degradates, pesticides and pesticide degradates, pharmaceutical compounds), constituents of special interest (perchlorate, 1,4-dioxane, and 1,2,3-trichlorpropane [1,2,3-TCP]), naturally occurring inorganic constituents (nutrients, major and minor ions, and trace elements), and radioactive constituents. Concentrations of naturally occurring isotopes (tritium, carbon-14, and stable isotopes of hydrogen and oxygen in water), and dissolved noble gases also were measured to help identify the sources and ages of the sampled groundwater. In total, approximately 220 constituents and water-quality indicators were investigated. Quality-control samples (blanks, replicates, and matrix spikes) were collected at approximately 30 percent of the wells, and the results were used to evaluate the quality of the data obtained from the groundwater samples. Field blanks rarely contained detectable concentrations of any constituent, suggesting that contamination was not a significant source of bias in the data. Differences between replicate samples were within acceptable ranges and matrix-spike recoveries were within acceptable ranges for most compounds. This study did not attempt to evaluate the quality of water delivered to consumers; after withdrawal from the ground, raw groundwater typically is treated, disinfected, or blended with other waters to maintain acceptable water quality. Regulatory thresholds apply to water that is served to the consumer, not to raw groundwater. However, to provide some context for the results, concentrations of constituents measured in the raw groundwater were compared to regulatory and nonregulatory health-based thresholds established by the U.S. Environmental Protection Agency (USEPA) and the California Department of Public Health (CDPH) and to thresholds established for aesthetic concerns by CDPH. Comparisons between data collected for this study and drinking-water thresholds are for illustrative purposes only and do not indicate compliance or noncompliance with those thresholds. The concentrations of most constituents detected in groundwater samples were below drinking-water thresholds. Volatile organic compounds (VOC) were detected in approximately 35 percent of grid well samples; all concentrations were below health-based thresholds. Pesticides and pesticide degradates were detected in about 20 percent of all samples; detections were below health-based thresholds. No concentrations of constituents of special interest or nutrients were detected above health-based thresholds. Most of the major and minor ion constituents sampled do not have health-based thresholds; the exception is chloride. Concentrations of chloride, sulfate, and total dissolved solids detected in some of the well samples were above the nonenforceable thresholds for aesthetic concerns. Concentrations of fluoride were detected in 5 samples (from 4 grid wells and 1 understanding well) above the maximum contaminant level for California (MCL-CA). Concentrations of most of the trace elements in samples from the COLOR study were below health-based thresholds; exceptions included arsenic above the MCL-US, boron above the notification level for California (NL-CA), iron and manganese above the secondary maximum contaminant level for California (SMCL-CA), and molybdenum and strontium above the lifetime health advisory level (HAL-US) threshold. Most detections of radioactive constituents were below health-based thresholds; exceptions were alpha, uranium, and radon radioactivity. Alpha radioactivity with 72 hour count detections occurred in four grid wells and one understanding well, and 30-day count detections in two grid wells above the MCL-US. Uranium was detected twice in grid wells above the MCL-US threshold. Also, radon-222 was detected at concentrations above the proposed MCL-US in 19 samples (14 grid and 5 understanding wells). No radon-222 was detected above the proposed MCL-US upper threshold.

California↗
USGS2009

Bathymetry and Near-River Topography of the Naches and Yakima Rivers at Union Gap and Selah Gap, Yakima County, Washington, August 2008

Yakima County is collaborating with the Bureau of Reclamation on a study of the hydraulics and sediment-transport in the lower Naches River and in the Yakima River between Union Gap and Selah Gap in Washington. River bathymetry and topographic data of the river channels are needed for the study to construct hydraulic models. River survey data were available for most of the study area, but river bathymetry and near-river topography were not available for Selah Gap, near the confluence of the Naches and Yakima Rivers, and for Union Gap. In August 2008, the U.S. Geological Survey surveyed the areas where data were not available. If possible, the surveys were made with a boat-mounted, single-beam echo sounder attached to a survey-grade Real-Time Kinematic (RTK) global positioning system (GPS). An RTK GPS rover was used on a walking survey of the river banks, shallow river areas, and river bed areas that were impenetrable to the echo sounder because of high densities of macrophytes. After the data were edited, 95,654 bathymetric points from the boat survey with the echo sounder and 1,069 points from the walking survey with the GPS rover were used in the study. The points covered 4.6 kilometers on the Yakima River and 0.6 kilometers on the Naches River. GPS-surveyed points checked within 0.014 to 0.047 meters in the horizontal direction and -0.036 to 0.078 meters in the vertical direction compared to previously established survey control points

Data Series↗
USGS2010

Cartographic Production for the FLaSH Map Study: Generation of Rugosity Grids, 2008

Project Summary This series of raster data is a U.S. Geological Survey (USGS) Data Series release from the Florida Shelf Habitat Project (FLaSH). This disc contains two raster images in Environmental Systems Research Institute, Inc. (ESRI) raster grid format, jpeg image format, and Geo-referenced Tagged Image File Format (GeoTIFF). Data is also provided in non-image ASCII format. Rugosity grids at two resolutions (250 m and 1000 m) were generated for West Florida shelf waters to 250 m using a custom algorithm that follows the methods of Valentine and others (2004). The Methods portion of this document describes the specific steps used to generate the raster images. Rugosity, also referred to as roughness, ruggedness, or the surface-area ratio (Riley and others, 1999; Wilson and others, 2007), is a visual and quantitative measurement of terrain complexity, a common variable in ecological habitat studies. The rugosity of an area can affect biota by influencing habitat, providing shelter from elements, determining the quantity and type of living space, influencing the type and quantity of flora, affecting predator-prey relationships by providing cover and concealment, and, as an expression of vertical relief, can influence local environmental conditions such as temperature and moisture. In the marine environment rugosity can furthermore influence current flow rate and direction, increase the residence time of water in an area through eddying and current deflection, influence local water conditions such as chemistry, turbidity, and temperature, and influence the rate and nature of sedimentary deposition. State-of-the-art computer-mapping techniques and data-processing tools were used to develop shelf-wide raster and vector data layers. Florida Shelf Habitat (FLaSH) Mapping Project (http://coastal.er.usgs.gov/flash) endeavors to locate available data, identify data gaps, synthesize existing information, and expand our understanding of geologic processes in our dynamic coastal and marine systems.

Data Series↗
USGS2009

EAARL Coastal Topography-Western Florida, Post-Hurricane Charley, 2004: First Surface

This DVD contains lidar-derived first-surface (FS) topography GIS datasets of a portion of the western Florida coastline beachface, acquired post-Hurricane Charley on August 16 and 18, 2004. Click on a tile number (1 - 68) to view the corresponding 1-meter-resolution images and links to each data directory. Click on the red tile in the index map to view the 3-meter-resolution mosaic and link to the corresponding directory.

Data Series↗
USGS2009

Groundwater-quality data in the Antelope Valley study unit, 2008: Results from the California GAMA Program

Groundwater quality in the approximately 1,600 square-mile Antelope Valley study unit (ANT) was investigated from January to April 2008 as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Project was developed in response to the Groundwater Quality Monitoring Act of 2001, and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). The study was designed to provide a spatially unbiased assessment of the quality of raw groundwater used for public water supplies within ANT, and to facilitate statistically consistent comparisons of groundwater quality throughout California. Samples were collected from 57 wells in Kern, Los Angeles, and San Bernardino Counties. Fifty-six of the wells were selected using a spatially distributed, randomized, grid-based method to provide statistical representation of the study area (grid wells), and one additional well was selected to aid in evaluation of specific water-quality issues (understanding well). The groundwater samples were analyzed for a large number of organic constituents (volatile organic compounds [VOCs], gasoline additives and degradates, pesticides and pesticide degradates, fumigants, and pharmaceutical compounds), constituents of special interest (perchlorate, N-nitrosodimethylamine [NDMA], and 1,2,3-trichloropropane [1,2,3-TCP]), naturally occurring inorganic constituents (nutrients, major and minor ions, and trace elements), and radioactive constituents (gross alpha and gross beta radioactivity, radium isotopes, and radon-222). Naturally occurring isotopes (strontium, tritium, and carbon-14, and stable isotopes of hydrogen and oxygen in water), and dissolved noble gases also were measured to help identify the sources and ages of the sampled groundwater. In total, 239 constituents and water-quality indicators (field parameters) were investigated. Quality-control samples (blanks, replicates, and samples for matrix spikes) were collected at 12 percent of the wells, and the results for these samples were used to evaluate the quality of the data for the groundwater samples. Field blanks rarely contained detectable concentrations of any constituent, suggesting that contamination was not a noticeable source of bias in the data for the groundwater samples. Differences between replicate samples generally were within acceptable ranges, indicating acceptably low variability. Matrix spike recoveries were within acceptable ranges for most compoundsThis study did not evaluate the quality of water delivered to consumers; after withdrawal from the ground, water typically is treated, disinfected, or blended with other waters to maintain water quality. Regulatory thresholds apply to water that is served to the consumer, not to raw groundwater. However, to provide some context for the results, concentrations of constituents measured in the raw groundwater were compared with regulatory and non-regulatory health-based thresholds established by the U.S. Environmental Protection Agency (USEPA) and California Department of Public Health (CDPH) and thresholds established for aesthetic concerns (secondary maximum contaminant levels, SMCL-CA) by CDPH. Comparisons between data collected for this study and drinking-water thresholds are for illustrative purposes only, and are not indicative of compliance or non-compliance with drinking water standards. Most constituents that were detected in groundwater samples were found at concentrations below drinking-water thresholds. Volatile organic compounds (VOCs) were detected in about one-half of the samples and pesticides detected in about one-third of the samples; all detections of these constituents were below health-based thresholds. Most detections of trace elements and nutrients in samples from ANT wells were below health-based thresholds. Exceptions include: one detection of nitrite plus nitrate as nitrogen (NO 2 +NO 3 ) above the USEPA maximum contaminant level (MCL-US: 10 mg/L), five detections of arsenic above the MCL-US (6 μg/L), one detection of boron above the CDPH notification level (NL-CA: 1,000 μg/L), and two detections of vanadium above the NL-CA (50 μg/L). Most detections of radioactive constituents were below health-based thresholds. Exceptions include two detections of gross alpha radioactivity (72-hour and 30-day counts) above the MCL-US (15 pCi/L). Also, radon-222 was detected above the proposed MCL-US (300 pCi/L) in 14 grid wells and the understanding well, but no wells had detections above the proposed alternative MCL-US (4,000 pCi/L). Most of the samples from ANT wells had concentrations of major elements, total dissolved solids (TDS), and trace elements below the non-enforceable thresholds set for aesthetic concerns. Three samples contained sulfate and four samples contained total dissolved solids at concentrations above the SMCL-CA thresholds (250 mg/L and 500 mg/L, respectively). Two of the total dissolved solids detections were above the upper SMCL-CA (1,000 mg/L). Samples from four wells had field pH values above the SMCL-US (>pH 8.5). Field-measured specific conductance values were above the SMCL-CA (900 μS/cm at 25°C) at eight wells with four of these measurements above the upper SMCL-CA threshold (1,600 μS/cm at 25°C).

California↗
USGS2010

A Compilation of Spatial Datasets to Support a Preliminary Assessment of Pesticides and Pesticide Use on Tribal Lands in Oklahoma

This CD-ROM contains spatial datasets that describe natural and anthropogenic features and county-level estimates of agricultural pesticide use and pesticide data for surface-water, groundwater, and biological specimens in the state of Oklahoma. County-level estimates of pesticide use were compiled from the Pesticide National Synthesis Project of the U.S. Geological Survey, National Water-Quality Assessment Program. Pesticide data for surface water, groundwater, and biological specimens were compiled from U.S. Geological Survey National Water Information System database. These spatial datasets that describe natural and manmade features were compiled from several agencies and contain information collected by the U.S. Geological Survey. The U.S. Geological Survey datasets were not collected specifically for this compilation, but were previously collected for projects with various objectives. The spatial datasets were created by different agencies from sources with varied quality. As a result, features common to multiple layers may not overlay exactly. Users should check the metadata to determine proper use of these spatial datasets. These data were not checked for accuracy or completeness. If a question of accuracy or completeness arise, the user should contact the originator cited in the metadata.

Data Series↗
USGS2010

EAARL Coastal Topography and Imagery-Naval Live Oaks Area, Gulf Islands National Seashore, Florida, 2007

These remotely sensed, geographically referenced color-infrared (CIR) imagery and elevation measurements of lidar-derived bare-earth (BE) topography, first-surface (FS) topography, and canopy-height (CH) datasets were produced collaboratively by the U.S. Geological Survey (USGS), St. Petersburg Science Center, St. Petersburg, FL; the National Park Service (NPS), Gulf Coast Network, Lafayette, LA; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the Naval Live Oaks Area in Florida's Gulf Islands National Seashore, acquired June 30, 2007. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative airborne lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multispectral CIR camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for sub-meter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of lidar data in an interactive or batch mode. Modules for presurvey flight-line definition, flight-path plotting, lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or sub-aerial topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations. For more information about similar projects, please visit the Decision Support for Coastal Science and Management website.

Data Series↗
USGS2009

Continuous and discrete water-quality data collected at five sites on Lake Houston near Houston, Texas, 2006-08

Lake Houston, a reservoir impounded in 1954 by the City of Houston, Texas, is a primary source of drinking water for Houston and surrounding areas. The U.S. Geological Survey, in cooperation with the City of Houston, developed a continuous water-quality monitoring network to track daily changes in water quality in the southwestern quadrant of Lake Houston beginning in 2006. Continuous water-quality data (the physiochemical properties water temperature, specific conductance, pH, dissolved oxygen concentration, and turbidity) were collected from Lake Houston to characterize the in-lake processes that affect water quality. Continuous data were collected hourly from mobile, multi-depth monitoring stations developed and constructed by the U.S. Geological Survey. Multi-depth monitoring stations were installed at five sites in three general locations in the southwestern quadrant of the lake. Discrete water-quality data (samples) were collected routinely (once or twice each month) at all sites to characterize the chemical and biological (phytoplankton and bacteria) response to changes in the continuous water-quality properties. Physiochemical properties (the five continuously monitored plus transparency) were measured in the field when samples were collected. In addition to the routine samples, discrete water-quality samples were collected synoptically (one or two times during the study period) at all sites to determine the presence and levels of selected constituents not analyzed in routine samples. Routine samples were measured or analyzed for acid neutralizing capacity; selected major ions and trace elements (calcium, silica, and manganese); nutrients (filtered and total ammonia nitrogen, filtered nitrate plus nitrite nitrogen, total nitrate nitrogen, filtered and total nitrite nitrogen, filtered and total orthophosphate phosphorus, total phosphorus, total nitrogen, total organic carbon); fecal indicator bacteria (total coliform and Escherichia coli); sediment (suspended-sediment concentration and loss-on-ignition); actinomycetes bacteria; taste-and-odor-causing compounds (2-methylisoborneol and geosmin); cyanobacterial toxins (total microcystins); and phytoplankton abundance, biovolume, and community composition (taxonomic identification to genus). Synoptic samples were analyzed for major ions, trace elements, wastewater indicators, pesticides, volatile organic compounds, and carbon. The analytical data are presented in tables by type (continuous, discrete routine, discrete synoptic) and listed by station number. Continuously monitored properties (except pH) also are displayed graphically.

Texas↗
USGS2010

High-Frequency, Crosswell Radar Data Collected in a Laboratory Tank

Crosswell radar data were collected among three wells in a laboratory tank filled with dry sand. Embedded within the sand was a long plastic box, which was the target for the data collection. Two datasets were collected between each pair of wells, making a total of six datasets. The frequencies in the data ranged from 0.5 to 1.5 gigahertz, and the peak frequency was 0.9 gigahertz. The data are well suited for evaluating various processing algorithms, and the data linearly scale to typical field conditions.

Data Series↗