Filters: Tags: Sediment (X)751 results (37ms)
Characterization of seafloor photographs near the mouth of the Elwha River during the first two years of dam removal (2011-2013)
We characterized seafloor sediment conditions near the mouth of the Elwha River from underwater photographs taken every four hours from September 2011 to December 2013. A digital camera was affixed to a tripod that was deployed in approximately 10 meters of water (Tripod location from September 2011 to April 2013: 48.15333, -123.55931; tripod location from April 2013 to December 2013: 48.15407, -123.55444). Each photograph was qualitatively characterized as one of six categories: (1) base, or no sediment; (2) low sediment; (3) medium sediment; (4) high sediment; (5) turbid; or (6) kelp. For base conditions, no sediment was present on the seafloor. Low sediment conditions were characterized by a light dusting of...
Water-quality and streamflow datasets used in the Weighted Regressions on Time, Discharge, and Season (WRTDS) models to determine trends in the Nation’s rivers and streams, 1972-2012(output)
In 1991, the U.S. Geological Survey (USGS) began a study of more than 50 major river basins across the Nation as part of the National Water-Quality Assessment (NAWQA) project of the National Water-Quality Program. One of the major goals of the NAWQA project is to determine how water-quality conditions change over time. To support that goal, long-term consistent and comparable monitoring has been conducted on streams and rivers throughout the Nation. Outside of the NAWQA project, the USGS and other Federal, State, and local agencies also have collected long-term water-quality data to support their own assessments of changing water-quality conditions. Data from these multiple sources have been combined to support...
This dataset depicts relative erosion rate derived for all land draining above the Mesoamerican reef. It is a function of slope, land cover type, precipitation and soil type. The indicators developed by the Reefs at Risk in the Caribbean project enable detailed comparative analyses of threats on many scales. The Reefs at Risk indicators are a simplification of human activities and complex natural processes. This data set was derived at the World Resources Institute for input to the sedimentation and pollution from watershed based sources threat analysis. Agriculture, though important to economic development and food security, is a source of increased sediment, nutrient, and pesticide runoff. Threats from sedimentation...
Using basins derived from a hydrologically-corrected 30m resolution DEM as a unit for summary statistics, we provide a series of indicators focused on land-based sources of threat within the US Virgin Islands and Puerto Rico. This includes indicators of a) the relative vulnerability of the land to erosion (based on slope, precipitation and soil erodibility); b) the relative erosion potential (REP) of the land, based on the relative vulnerability of the land, coupled with the current land cover type; c) the sediment delivery rate for each basin (percentage of eroded which reaches the river mouth); d) estimated sediment delivery for the basin, given current land use;
Geochemical reanalysis of historical U.S. Geological Survey sediment samples from the Tonsina area, Valdez Quadrangle, Alaska
The State of Alaska's Strategic and Critical Minerals (SCM) Assessment project, a State-funded Capital Improvement Project (CIP), is designed to evaluate Alaska's statewide potential for SCM resources. The SCM Assessment is being implemented by the Alaska Division of Geological & Geophysical Surveys (DGGS), and involves obtaining new airborne-geophysical, geological, and geochemical data. For the geochemical part of the SCM Assessment, thousands of historical geochemical samples from DGGS, U.S. Geological Survey (USGS), and U.S. Bureau of Mines archives are being reanalyzed by DGGS using modern, quantitative, geochemical-analytical methods. The objective is to update the statewide geochemical database to more clearly...
This metadata record documents 11 comma delimited tables representing the amount of reported best management practice (BMP) implementation for the years from 1985 to 2014 at three geographic scales: county or land-river modeling segment, River Input Monitoring (RIM) station drainage areas, and the entire Chesapeake Bay Watershed (CBWS). Data originated from the Chesapeake Bay Watershed jurisdictions including Maryland, Pennsylvania, Virginia, Delaware, New York, West Virginia, and the District of Columbia. Data were reported to the Chesapeake Bay Program for an annual review of progress toward meeting nitrogen, phosphorus, and sediment reduction goals.
This project assessed the potential effects of climate change on tidal marsh habitats and bird populations, identified priority sites for tidal marsh conservation and restoration, and developed a web-based mapping tool for managers to interactively display and query results. Project results can be found at PRBO’s San Francisco Bay Sea-Level Rise Website
SILVIES CANYON WATERSHED RESTORATION PROJECT, BURNS AND BEAR VALLEY RANGER DISTRICTS, MALHEUR NATIONAL FOREST, GRANT AND HARNEY COUNTIES, OREGON (DRAFT SUPPLEMENT TO THE DRAFT ENVIRONMETNAL IMPACT STATEMENT OF FEBRUARY 2001)
IMPLEMENTATION AGREEMENT, INADVERTENT OVERRUN AND PAYBACK POLICY, AND RELATED ACTIONS, LOWER COLORADO RIVER AND THE STATES OF ARIZONA, CALIFORNIA, AND NEVADA.
Estuarine macrobenthic community structure in the Hawkesbury River, Australia: Relationships with sediment physicochemical and anthropogenic parameters
Anthropogenic organic contaminants in the effluent of a combined sewer overflow: impact on Boston Harbor