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Filters: Tags: Global Positioning System (GPS) observations (X) > Types: OGC WMS Layer (X)

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This portion of the USGS data release presents eelgrass distribution and bathymetry data derived from acoustic surveys of the Nisqually River delta, Washington in 2014 (USGS Field Activity Number D-01-14-PS). Eelgrass and bathymetry data were collected from the R/V George Davidson equipped with a single-beam sonar system and global navigation satellite system (GNSS) receiver. The sonar system consisted of a Biosonics DT-X single-beam echosounder and 420 kHz transducer with a 6-degree beam angle. Depths from the echosounder were computed using sound velocity data measured using a YSI CastAway CTD during the survey. Positioning of the survey vessel was determined at 5 to 10 Hz using a Trimble R7 GNSS receiver and...
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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 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...
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This portion of the USGS data release presents topography data collected during surveys performed on the Elwha River delta, Washington, in July 2015 (USGS Field Activity Number 2015-648-FA). Topography data were collected on foot with global navigation satellite systems (GNSS) equipment mounted on backpacks operating primarily in Real-Time Kinematic (RTK) mode. A total of 5 GNSS backpacks, each equipped with a dual-frequency GNSS receiver and handheld data collector, were used during the survey. Differential corrections were transmitted at 1-Hz intervals by a VHF radio to the backpack GNSS receivers from a GNSS base station placed on a benchmark with known horizontal and vertical coordinates relative to the North...
map background search result map search result map Topography data from the Elwha River delta, Washington, July 2015 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 Eelgrass distributions and bathymetry derived from an acoustic survey of the Nisqually River delta, Washington, 2014 Nearshore bathymetry of the Columbia River littoral cell, Washington and Oregon, 2021 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 Eelgrass distributions and bathymetry derived from an acoustic survey of the Nisqually River delta, Washington, 2014 Topography data from the Elwha River delta, Washington, July 2015 Nearshore bathymetry of the Columbia River littoral cell, Washington and Oregon, 2021