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Filters: Tags: Global Positioning System (GPS) observations (X) > Date Range: {"choice":"year"} (X)

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This portion of the USGS data release presents bathymetry data collected during surveys performed in the Columbia River littoral cell, Washington and Oregon in 2018 (USGS Field Activity Number 2018-652-FA). Bathymetry data were collected using four personal watercraft (PWCs) equipped with single-beam sonar systems and global navigation satellite system (GNSS) receivers. The sonar systems consisted of an Odom Echotrac CV-100 single-beam echosounder and 200 kHz transducer with a 9 degree beam angle. Raw acoustic backscatter returns were digitized by the echosounder with a vertical resolution of 1.25 cm. Depths from the echosounders were computed using sound velocity profiles measured using a YSI CastAway CTD during...
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This portion of the USGS data release presents digital elevation models (DEMs) derived from bathymetric and topographic surveys conducted on the Elwha River delta in August 2022 (USGS Field Activity Number 2022-638-FA). Nearshore bathymetry data were collected using two personal watercraft (PWCs) and a kayak equipped with single-beam echosounders and survey-grade global navigation satellite systems (GNSS) receivers. Topographic data were collected on foot with survey-grade GNSS receivers mounted on backpacks. Positions of the survey platforms were referenced to a GNSS base station placed on a benchmark with known horizontal and vertical coordinates relative to the North American Datum of 1983 (CORS96 realization)...
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Two dams on the Elwha River, Washington State, USA trapped over 20 million m3 of sediment, reducing downstream sediment fluxes and contributing to erosion of the river's coastal delta. The removal of the Elwha and Glines Canyon dams between 2011 and 2014 induced massive increases in river sediment supply and provided an unprecedented opportunity to examine the response of a delta system to changes in sediment supply. The U.S. Geological Survey (USGS) developed an integrated research program aimed at understanding the ecosystem responses following dam removal. The research program included repeated surveys of beach topography, nearshore bathymetry, and surface sediment grain size to quantify changes in delta morphology...
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This portion of the USGS data release presents sediment grain-size data from samples collected on the Elwha River delta, Washington, in August 2012 (USGS Field Activity Number W-05-12-PS). Surface sediment was sampled using a small ponar, or 'grab', sampler between August 28 and August 30, 2012 from the R/V Frontier at a total of 57 locations in water depths between about 1 and 9 m around the delta. A handheld global satellite navigation system (GNSS) receiver was used to determine the locations of sediment samples. Grab samples that yielded less than 50 g of sediment were omitted from analysis and are classified as "no sample". The grain-size distributions of samples that yielded more than 50 g of sediment were...
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This portion of the USGS data release presents sediment grain-size data from samples collected on the Elwha River delta, Washington, in March 2013 (USGS Field Activity Number W-01-13-PS). Surface sediment was sampled using a small ponar, or 'grab', sampler on March 4, 2013 from the R/V Frontier at a total of 48 locations in water depths between about 1 and 12 m around the delta. An additional 7 sediment samples were collected between March 6 and March 7, 2013 at low tide from intertidal locations on the delta. A handheld global satellite navigation system (GNSS) receiver was used to determine the locations of sediment samples. Grab samples that yielded less than 50 g of sediment were omitted from analysis and are...
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This portion of the USGS data release presents sediment grain-size data from samples collected on the Elwha River delta, Washington, in May 2014 (USGS Field Activity Number 2014-620-FA). Surface sediment was collected on May 12, 2014, at a total of 43 locations using a small ponar, or 'grab', sampler from a small boat in water depths between approximately 1 and 12 m around the delta. A hand-held global satellite navigation system (GNSS) receiver was used to determine the locations of sediment samples. The grain-size distributions of samples were determined in the USGS Pacific Coastal and Marine Science Center sediment lab. Approximately 20 g of sediment was sub-sampled and 10 mL of 35 percent hydrogen peroxide...
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This data release presents nearshore bathymetry data collected at the mouth of the Unalakleet River in Alaska, near the city of Unalakleet. The data were collected in August 2019 by the U.S. Geological Survey, Pacific Coastal and Marine Science Center. Nearshore bathymetry was measured along survey lines from the shore to a depth of approximately -7.4 m NAVD88 and in a portion of the estuary closest to the mouth. Bathymetry data were collected using small boat equipped with a single-beam sonar system and global navigation satellite system (GNSS) receiver. The sonar system consisted of an Odom Echotrac CV-100 single-beam echosounder and 200 kHz transducer with a 9 degree beam. Depths from the seafloor to the echosounder...
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This portion of the USGS data release presents bathymetry data collected during surveys performed in the Columbia River littoral cell, Washington and Oregon in 2021 (USGS Field Activity Number 2021-632-FA). Bathymetry data were collected using four personal watercraft (PWCs) equipped with single-beam sonar systems and global navigation satellite system (GNSS) receivers. The sonar systems consisted of an Odom Echotrac CV-100 single-beam echosounder and 200 kHz transducer with a 9-degree beam angle. Raw acoustic backscatter returns were digitized by the echosounder with a vertical resolution of 1.25 cm. Depths from the echosounders were computed using sound velocity profiles measured using a YSI CastAway CTD during...
map background search result map search result map Surface-sediment grain-size distributions from the Elwha River delta, Washington, May 2014 Surface-sediment grain-size distributions from the Elwha River delta, Washington, March 2013 Surface-sediment grain-size distributions from the Elwha River delta, Washington, August 2012 Bathymetry, topography, and sediment grain-size data from the Elwha River delta, Washington Nearshore bathymetry of the Columbia River littoral cell, Washington and Oregon, 2018 Nearshore bathymetry data from the Unalakleet River mouth, Alaska, 2019 Nearshore bathymetry of the Columbia River littoral cell, Washington and Oregon, 2021 Digital elevation models (DEMs) of the Elwha River delta, Washington, August 2022 Surface-sediment grain-size distributions from the Elwha River delta, Washington, May 2014 Surface-sediment grain-size distributions from the Elwha River delta, Washington, March 2013 Surface-sediment grain-size distributions from the Elwha River delta, Washington, August 2012 Digital elevation models (DEMs) of the Elwha River delta, Washington, August 2022 Nearshore bathymetry data from the Unalakleet River mouth, Alaska, 2019 Nearshore bathymetry of the Columbia River littoral cell, Washington and Oregon, 2018 Nearshore bathymetry of the Columbia River littoral cell, Washington and Oregon, 2021