Andrew W. Stevens
Guy Gelfenbaum
Jonathan A. Warrick
Ian M. Miller
Heather M. Weiner
2017
Digital elevation models (DEMs) of the Elwha River delta, Washington, May 2012
Esri ARC/INFO ASCII GRID
data release
DOI:10.5066/F78G8HWT
Santa Cruz, CA
U.S. Geological Survey
https://doi.org/10.5066/F78G8HWT
Andrew W. Stevens
Guy Gelfenbaum
Jonathan A. Warrick
Ian M. Miller
Heather M. Weiner
2017
Bathymetry and topography data from the Elwha River delta, Washington, May 2012
data release
DOI:10.5066/F78G8HWT
Santa Cruz, CA
U.S. Geological Survey
https://doi.org/10.5066/F78G8HWT
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 May 2012. 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 W-03-12-PS). 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.
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.
Additional information about the field activities from which these data were derived are available online at:
https://cmgds.marine.usgs.gov/fan_info.php?fan=W0312PS
20120518
20120520
ground condition at time data were collected
Not planned
-123.586310
-123.532513
48.157568
48.137172
USGS Metadata Identifier
USGS:58531380e4b0e2663625f195
USGS Thesaurus
bathymetry
bathymetry measurement
topography
GPS measurement
digital elevation models
Data Categories for Marine Planning
Bathymetry and Elevation
Marine Realms Information Bank (MRIB) keywords
single-beam echo sounder
topographic mapping
Global Positioning System (GPS) observations
ISO 19115 Topic Category
elevation
Global Change Master Directory (GCMD)
Water Depth
GPS (Global Positioning System)
Echo Sounders
none
USGS-authored or produced data and information are in the public domain from the U.S. Government and are freely redistributable with proper metadata and source attribution. Please recognize and acknowledge the U.S. Geological Survey as the originator(s) of the dataset and in products derived from these data. This information is not intended for navigational purposes.
Andrew W. Stevens
U.S. Geological Survey, Pacific Coastal and Marine Science Center
mailing and physical
2885 Mission St.
Santa Cruz
CA
95060
USA
831-460-7424
astevens@usgs.gov
https://www.sciencebase.gov/catalog/file/get/58531380e4b0e2663625f195?name=ew12_may_dem_5m.png&allowOpen=true
image map showing 5-m resolution digital elevation model (DEM) of Elwha River delta, color-coded to show elevation
PNG
https://www.sciencebase.gov/catalog/file/get/58531380e4b0e2663625f195?name=ew12_may_dem_1m.png&allowOpen=true
image map showing 1-m resolution digital elevation model (DEM) of Elwha River mouth, color-coded to show elevation
PNG
Matlab version 9.0.0.341360 running on Microsoft Windows 7
International Hydrographic Organization (IHO)
2008
IHO standards for hydrographic surveys (5th ed.)
comma-delimited ascii
Monaco
International Hydrographic Bureau Special Publication 44, 28p.
https://www.iho.int/iho_pubs/standard/S-44_5E.pdf
Repeatability tests were conducted across different survey platforms, but no comparisons to "true" values were conducted.
All data fall within expected ranges.
Dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details.
Digital elevation models (DEMs) are created by interpolating between elevation measurements as much as 50 meters apart, for this reason we cannot evaluate the accuracy of each point in a DEM, only the original data from which it is generated. The horizontal accuracy of the individual points was assessed based on the combined uncertainty of GNSS base stations and kinematic (rover) data points. Manufacturer-reported accuracy for the differentially corrected horizontal positions for the Trimble R7, R8 and R10 receivers used to collect the topographic and bathymetric measurements is 0.8 cm + 0.5 ppm. Baselines from the GNSS base station were typically less than 5 km, suggesting a horizontal accuracy of survey-vessel positions to be 0.825 cm relative to the base station. The combined horizontal uncertainty from the base station coordinate solutions and rover trajectories is between 1.5 cm and 7 cm, with a mean horizontal uncertainty of 3 cm. Uncertainty in the horizontal positions associated with pitch and roll of the survey vessels and variable surveyor posture during the backpack surveys is unknown.
Digital elevation models (DEMs) are created by interpolating between elevation measurements as much as 50 meters apart, for this reason we cannot evaluate the accuracy of each point in a DEM, only the original data from which it is generated. An estimated vertical accuracy of 5 cm for the topographic GNSS backpack survey platforms was estimated by combining uncertainty in the base station coordinates and the manufacturer reported vertical accuracy of 1.5 cm + 1 ppm for differential corrected kinematic data. Additional uncertainty in the final computed elevations in the bathymetry data is related to unmeasured variability in the speed of sound used to compute depths from bathymetric soundings and, thus, are depth dependent. Based on analysis of all available sound velocity casts, we estimate the uncertainty in the final elevations to be 0.6 percent of water depth. The total vertical uncertainty is calculated using the standard equation sigmat=sqrt(a^2+(b×d)^2), where sigmat is the total vertical uncertainty, a is the uncertainty of the GNSS vertical position, b is the depth-dependent uncertainty factor (0.006), and d is water depth (International Hydrographic Organization, 2008). Maximum water depths surveyed by the personal watercraft are approximately 18 m, yielding a maximum total vertical uncertainty of 12 cm.
Andrew W. Stevens
Guy Gelfenbaum
Jonathan A. Warrick
Ian M. Miller
Heather M. Weiner
2017
Nearshore bathymetry data from the Elwha River delta, Washington, May 2012
comma-delimited text
online
U.S. Geological Survey, Pacific Coastal and Marine Science Center
https://www.sciencebase.gov/catalog/file/get/58531397e4b0e2663625f199
digital dataset
20120518
20120520
ground condition at time data were collected
bathymetry data
Bathymetry data were combined with topography data, and then interpolated into a gridded surface
Andrew W. Stevens
Guy Gelfenbaum
Jonathan A. Warrick
Ian M. Miller
Heather M. Weiner
2017
Topography data from the Elwha River delta, Washington, May 2012
comma-delimited text
online
U.S. Geological Survey, Pacific Coastal and Marine Science Center
https://www.sciencebase.gov/catalog/file/get/585313b0e4b0e2663625f19b
digital dataset
20120518
20120520
ground condition at time data were collected
topography data
Topography data were combined with bathymetry data, and then interpolated into a gridded surface
Quality control was applied to raw topography and bathymetry data. Comparisons were performed to ensure internal consistency between the survey platforms. DEMs were produced by linear interpolation of all available elevation point data with the computer program MATLAB. Data were exported in Esri ARC/INFO ASCII GRID format for distribution.
all sources cited were used
20120525
Edited metadata to add keywords section with USGS persistent identifier as theme keyword. No data were changed.
20201019
U.S. Geological Survey
VeeAnn A. Cross
Marine Geologist
Mailing and Physical
384 Woods Hole Road
Woods Hole
MA
02543-1598
508-548-8700 x2251
508-457-2310
vatnipp@usgs.gov
Performed minor edits to the metadata to correct typos. No data were changed
20211014
U.S. Geological Survey
Susan A. Cochran
Geologist
Mailing and Physical
2885 Mission Street
Santa Cruz
CA
95060
831-460-7545
scochran@usgs.gov
Raster
Lambert Conformal Conic
47.5
48.73333333333333
-120.8333333333333
47.0
500000.0
0.0
coordinate pair
0.01
0.01
METERS
NAD83 (CORS96)
GRS_1980
6378137.0
298.257222101
North American Vertical Datum of 1988
0.01
meters
Explicit elevation coordinate included with horizontal coordinates
Attribute Table
Table containing attribute information associated with the dataset
Producer defined
Elevation
Elevation relative to the North American Vertical Datum of 1988 at the base station (-20.11 m above the reference ellipsoid).
Producer Defined
-18.03
5.69
meters
U.S. Geological Survey - Science Base
U.S. Geological Survey
mailing and physical
Denver Federal Center, Building 810, Mail Stop 302
Denver
CO
80225
USA
1-888-275-8747
sciencebase@usgs.gov
DEM grids are available in Esri ARC/INFO ASCII GRID format (ew12_may_dem_5m.asc; ew12_may_dem_1m.asc), along with low-resolution browse graphics of each DEM in png format (ew12_may_dem_5m.png; ew12_may_dem_1m.png) and associated metadata (ew12_may_dem.xml).
Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.
ASCII
ArcGIS 10.1
Esri ARC/INFO ASCII GRID
Esri ASCII raster file containing 5-m resolution digital elevation model of the Elwha River delta
none
2.6
https://www.sciencebase.gov/catalog/file/get/58531380e4b0e2663625f195/?name=ew12_may_dem_5m.asc
Data can be downloaded via the Internet
png
Matlab 9.0.0.341360
PNG Image
PNG image showing 5-m resolution digital elevation model of the Elwha River delta
none
0.7
https://www.sciencebase.gov/catalog/file/get/58531380e4b0e2663625f195/?name=ew12_may_dem_5m.png
Data can be downloaded via the Internet
ASCII
ArcGIS 10.1
Esri ARC/INFO ASCII GRID
Esri ASCII raster file containing 1-m resolution digital elevation model of the Elwha River mouth
none
14.6
https://www.sciencebase.gov/catalog/file/get/58531380e4b0e2663625f195/?name=ew12_may_dem_1m.asc
Data can be downloaded via the Internet
png
Matlab 9.0.0.341360
PNG Image
PNG image showing 1-m resolution digital elevation model of the Elwha River mouth
none
1.0
https://www.sciencebase.gov/catalog/file/get/58531380e4b0e2663625f195/?name=ew12_may_dem_1m.png
Data can be downloaded via the Internet
None
20211014
U.S. Geological Survey, Pacific Coastal and Marine Science Center
PCMSC Science Data Coordinator
mailing and physical
2885 Mission Street
Santa Cruz
CA
95060-5792
US
831-427-4747
pcmsc_data@usgs.gov
Content Standard for Digital Geospatial Metadata
FGDC-STD-001-1998