Eelgrass distributions and bathymetry of the Nisqually River delta, Washington, 2014
Dates
Start Date
2014-02-22
End Date
2014-02-25
Publication Date
2020-07-21
Citation
Stevens, A.W., Takesue, R.K., and Grossman, E.E., 2020, Eelgrass distributions and bathymetry of the Nisqually River delta, Washington: U.S. Geological Survey data release, https://doi.org/10.5066/P9N9K2I1.
Summary
This USGS data release presents data collected during surveys of eelgrass distributions and bathymetry on the Nisqually River delta, Washington. Survey operations were conducted between February 22 and February 25, 2014 (USGS Field Activity Number D-01-14-PS) by a team of scientists from the U.S. Geological Survey Pacific Coastal and Marine Science Center and Washington State Department of Ecology. The distributions of eelgrass and bathymetry data were collected using a single-beam echosounder and survey-grade global navigation satellite system (GNSS) receiver. Positions of the survey platform were referenced to a GNSS base station placed on a nearby benchmark with known horizontal and vertical coordinates. Depths from the echosounder [...]
Summary
This USGS data release presents data collected during surveys of eelgrass distributions and bathymetry on the Nisqually River delta, Washington. Survey operations were conducted between February 22 and February 25, 2014 (USGS Field Activity Number D-01-14-PS) by a team of scientists from the U.S. Geological Survey Pacific Coastal and Marine Science Center and Washington State Department of Ecology.
The distributions of eelgrass and bathymetry data were collected using a single-beam echosounder and survey-grade global navigation satellite system (GNSS) receiver. Positions of the survey platform were referenced to a GNSS base station placed on a nearby benchmark with known horizontal and vertical coordinates. Depths from the echosounder were computed using sound velocity profiles measured with a conductivity-temperature-depth (CTD) sensor during the survey. The raw acoustic data were classifed using a supervised signal processing technique to determine the presence of eelgrass along the survey tracklines. A towed underwater video camera was used to ground truth the acoustically derived eelgrass distribution maps. Figure 1 shows the locations of acoustic- and underwater video survey lines, sound velocity profile measurements, and GNSS base station used for geodetic control during the survey.
Digital files containing the eelgrass and bathymetry point data from acoustic and underwater video surveys are available for download from the Child Items section below.
Figure 1. Map showing the locations of acoustic- and underwater video-survey lines, sound velocity profile measurements, and benchmarks used for geodetic control during the 2014 survey of eelgrass distributions and bathymetry on the Nisqually River delta, Washington.
Click on title to download individual files attached to this item.
nq14_coverage_map.png “Map showing survey lines for the Nisqually River delta, 2014”
2.54 MB
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Purpose
Data were obtained to document interannual changes in eelgrass distributions and coastal morphology following the removal of a dike that restored tidal processes to over 300 ha of former freshwater wetlands on the Nisqually River delta in 2009. 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 the distributions of eelgrass and shallow-water bathymetric features.
Preview Image
Map showing survey lines for the Nisqually River delta, 2014