Bathymetry, topography, and sediment grain-size data from the Elwha River delta, Washington, April and May 2014
Dataset Identification:
Resource Abstract:
Two dams on the Elwha River, Washington State, USA trapped over 20 million m<sup>3</sup> 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 and texture
following the dam removals. For more information on the USGS role in the Elwha River Restoration Project, please visit <a
href="http://walrus.wr.usgs.gov/elwha/">http://walrus.wr.usgs.gov/elwha/</a>. <br> <br> This USGS data release presents
data collected during surveys of nearshore bathymetry, beach topography, and surface sediment grain size from the Elwha River
delta, Washington. Bathymetry and topography data were collected between April 26 and April 29, 2014, and surface sediment
samples were collected on May 12, 2014 (USGS Field Activity Number 2014-620-FA). The survey team included scientists from
the U.S. Geological Survey Pacific Coastal and Marine Science Center (PCMSC), Washington State Department of Ecology (WA DOE),
Washington Sea Grant, and University of Washington (table 1). <br> <br> Nearshore 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. Positions of the survey
platforms were referenced to a GNSS base station placed on a nearby benchmark with known horizontal and vertical coordinates.
Depths from the echosounders were computed using sound velocity profiles measured with a conductivity-temperature-depth (CTD)
sensor during the survey. A total of 150 km of nearshore bathymetric survey lines and 130 km of topographic survey lines
were collected during the 4 days of survey operations. Swift currents resulting from high river discharge during the survey
limited access to portions of the river mouth that have normally been sampled by topographic surveyors on foot. Despite the
challenge of high river flow, good coverage of the beach and nearshore region was achieved using the combination of methods
described above. Surface sediment was sampled using a small ponar, or 'grab', sampler on May 12, 2014 from a small boat
at a total of 43 locations in water depths between about 1 and 12 m around the delta. Figure 1 (top) shows the locations of
bathymetric- and topographic-survey lines, sediment samples, CTD samples, and GNSS base stations. A continuous DEM surface
of the primary survey area was produced from all available bathymetry and topography data using linear interpolation and a
grid-spacing of 5 m. Figure 1 (bottom) shows the bathymetry and topography data for areas adjacent to the river mouth color-coded
by elevation. An additional DEM with 1-m resolution grid-spacing was produced using linear interpolation for this smaller
region.<br> <br> Digital files containing the nearshore bathymetry data, beach topography data, derived DEMs, and grain-size
data from this survey are available for download from the child item pages listed below.<br> <table border="1" cellpadding="1"
cellspacing="1" style="width:500px"> <caption>Table 1. List of survey personnel</caption> <tbody> <tr> <td>Person</td> <td>Title</td>
<td>Affiliation</td> </tr> <tr> <td>Guy Gelfenbaum</td> <td>Research Oceanographer</td> <td>USGS PCMSC</td> </tr> <tr> <td>Jackson
Currie</td> <td>Physical Science Technician</td> <td>USGS PCMSC</td> </tr> <tr> <td>Andrew Stevens</td> <td>Oceanographer</td>
<td>USGS PCMSC</td> </tr> <tr> <td>Heather Weiner</td> <td>Coastal Geomatics Specialist</td> <td>WA DOE</td> </tr> <tr> <td>Diana
McCandless</td> <td>Environmental Specialist</td> <td>WA DOE</td> </tr> <tr> <td>Amanda Hacking</td> <td>Environmental Specialist</td>
<td>WA DOE</td> </tr> <tr> <td>Kasey Bowles</td> <td>Field Technician</td> <td>WA DOE</td> </tr> <tr> <td>Ian Miller </td>
<td>Coastal Hazards Specialist</td> <td>Washington Sea Grant</td> </tr> <tr> <td>Julia Dolan</td> <td>Undergraduate Student</td>
<td>University of Washington</td> </tr> <tr> <td>Sarra Tekola</td> <td>Undergraduate Student</td> <td>University of Washington</td>
</tr> </tbody> </table> <br> <img alt="" src="https://www.sciencebase.gov/catalog/file/get/584994d5e4b06d80b7b09558?f=__disk__52%2Ffe%2F6b%2F52fe6b3f8a8554b6572e4ca87cdb9a3d03aaa38e"
style="height:513px; width:500px"><br> <strong>Figure 1.</strong> Top: Map showing locations of bathymetric- and topographic-survey
lines, sediment samples, CTD casts, and GNSS base stations from the April and May 2014 survey of the Elwha River delta, Washington.
Bottom: Zoomed in detail of top map showing bathymetric- and topographic-survey lines color-coded by elevation.
Citation
Title Bathymetry, topography, and sediment grain-size data from the Elwha River delta, Washington, April and May 2014
other Citation Details
Cinergi keyword enhanced.File generated at Wed Jun 27 05:13:54 UTC 2018
purpose:
Data were obtained to assess the coastal geomorphic response following the removal of two dams on the Elwha River. These data
are intended for science researchers, students, policy makers, and the general public. These data can be used with geographic
information systems or other software to identify topographic and shallow-water bathymetric features.