| Digital elevation models (DEMs) of the Elwha River delta, Washington, April 2014 |
Trimble R7 GPS (AS) |
This part of the data release presents a digital elevation model (DEM) derived from bathymetry and topography data of the Elwha River delta collected in April 2014. 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 developed an integrated research program aimed at understanding the ecosystem responses following dam removal that included regular monitoring of coastal and nearshore bathymetry and topography. As part of this monitoring program, the USGS conducted a bathymetric and topographic survey in the Strait of Juan de Fuca on the Elwha River delta, Washington (USGS Field Activity Number 2014-620-FA). Bathymetry data were collected using two personal watercraft (PWCs), each equipped with single-beam echosounders and survey-grade global navigation satellite system (GNSS) receivers. Topography data were collected on foot with GNSS receivers mounted on backpacks. DEM surfaces were produced from all available elevation data using linear interpolation. |
Andrew Stevens |
| Topography data from the Elwha River delta, Washington, April 2014 |
Trimble R7 GPS (AS) |
This part of the data release presents topography data from the Elwha River delta collected in April 2014. Topography data were collected on foot with global navigation satellite system (GNSS) receivers mounted on backpacks. |
Andrew Stevens |
| Surface-sediment grain-size distributions from the Elwha River delta, Washington, May 2014 |
Ponar grab sampler |
This portion of the data release presents sediment grain-size data from samples collected on the Elwha River delta, Washington, in May 2014 (USGS Field Activity 2014-620-FA). Surface sediment was collected from 43 locations using a small ponar, or 'grab', sampler from a small boat on May 12, 2014 in depths between about 1 and 12 m around the delta. The locations of grab samples were determined with a hand-held global navigation satellite system (GNSS). The grain-size distributions of samples were determined using standard techniques developed by the USGS Pacific Coastal and Marine Science Center sediment lab. Grab samples that yielded less than 50 g of sediment were omitted from analysis and are classified as "no sample". The grain-size data are provided in a comma-delimited spreadsheet (.csv). |
Andrew Stevens |
| Nearshore bathymetry data from the Elwha River delta, Washington, April 2014, collected from personal watercraft |
waverunners |
This part of the data release presents bathymetry data from the Elwha River delta collected in April 2014 using two personal watercraft (PWCs). The PWCs were equipped with single-beam echosounders and survey-grade global navigation satellite system (GNSS) receivers. |
Andrew Stevens |
