Bathymetry, topography, and sediment grain-size data from the Elwha River delta, Washington, July 2016
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. Survey operations were conducted between July 17 and July 20, 2016 (USGS Field Activity Number 2016-653-FA)
by a team of 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 National Park Service (table 1). <br> <br> Nearshore bathymetry
data were collected using two personal watercraft (PWCs) and a kayak, each equipped with single-beam echosounders and survey-grade
global navigation satellite systems (GNSS). Topography data were collected on foot with GNSS 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 182 km of nearshore bathymetric survey lines and 191 km of topographic survey
lines were collected during the 4 days of survey operations. Environmental conditions were favorable resulting in excellent
coverage of the beach and nearshore region. Surface sediment was sampled using a small ponar, or 'grab', sampler on July 20,
2016 from the R/V Frontier at a total of 67 locations in water depths between about 1 and 17 m around the delta. An additional
38 sediment samples were collected between July 18 and July 19, 2016 at low tide from intertidal locations on the delta.
A handheld GNSS receiver was used to determine the locations of sediment samples. 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>Jonathan
Warrick </td> <td>Research Geologist</td> <td>USGS PCMSC</td> </tr> <tr> <td>Tim Elfers</td> <td>Engineering 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>Michelle
Gostic</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>Andy Ritchie</td> <td>Geomorphologist</td> <td>National Park Service</td> </tr>
</tbody> </table> <br> <img alt="" src="https://www.sciencebase.gov/catalog/file/get/582f34abe4b04d580bd48b77?f=__disk__63%2F01%2F76%2F6301763380bdd5c4a3642333d69f7e62f7f0c0b0"
style="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 July 2016 survey of the Elwha River delta, Washington.
Bottom: Zoomed in detail of top map showing bathymetric- and topographic-survey lines color-coded by elevation.<br>
Citation
Title Bathymetry, topography, and sediment grain-size data from the Elwha River delta, Washington, July 2016
other Citation Details
Cinergi keyword enhanced.File generated at Wed Jun 27 04:55:55 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.