Bathymetry and seafloor acoustic backscatter of mobile subaqueous sand dunes in the lower Columbia River, Washington and Oregon, 2021

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What does this data set describe?

Title:
Bathymetry and seafloor acoustic backscatter of mobile subaqueous sand dunes in the lower Columbia River, Washington and Oregon, 2021
Abstract:
Bathymetry and seafloor acoustic backscatter data were collected at four sites (SKM, SLG, LDB, WLW) using a SWATHPlus interferometric sonar (234 kHz) pole mounted to the R/V Parke Snavely during a June 2021 survey of the lower Columbia River, Washington and Oregon. Each site was surveyed repeatedly between June 5 and June 9, 2021 to quantify bathymetric changes resulting from migration of subaqueous sand dunes. The bathymetry and seafloor acoustic backscatter data from each site are provided as GeoTIFF images.
Supplemental_Information:
Additional information about the field activity from which these data were derived is available online at:
https://cmgds.marine.usgs.gov/fan_info.php?fan=2021-621-FA
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Although this Federal Geographic Data Committee-compliant metadata file is intended to document the data set in nonproprietary form, as well as in Esri format, this metadata file may include some Esri-specific terminology.
  1. How might this data set be cited?
    Dartnell, Peter, Stevens, Andrew W., Hatcher, Gerald A., and Ferro, Peter Dal, 20230808, Bathymetry and seafloor acoustic backscatter of mobile subaqueous sand dunes in the lower Columbia River, Washington and Oregon, 2021: data release DOI:10.5066/P92U1KPY, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

    This is part of the following larger work.

    Stevens, Andrew W., Hatcher, Gerald A., Ferro, Peter Dal, Dartnell, Peter, Warrick, Jonathan A., Cohn, Nicholas, and Moritz, Hans R., 2023, Digital seafloor images, sediment grain size, bathymetry, and water velocity data from the lower Columbia River, Washington and Oregon, 2021: data release DOI:10.5066/P92U1KPY, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

    Online Links:

    Other_Citation_Details:
    Suggested Citation: Suggested Citation: Stevens, A.W., Hatcher, G.A., Dal Ferro, P., Warrick, J.A., Cohn, N., and Moritz, H.R., 2023, Digital seafloor images, sediment grain size, bathymetry, and water velocity data from the lower Columbia River, Washington and Oregon, 2021: U.S. Geological Survey data release, https://doi.org/10.5066/P92U1KPY.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -123.443290
    East_Bounding_Coordinate: -122.761974
    North_Bounding_Coordinate: 46.250887
    South_Bounding_Coordinate: 45.712158
  3. What does it look like?
    dgs_swath_results.png (PNG)
    Image showing maps of bathymetric data collected at each site, color-coded by elevation
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 05-Jun-2021
    Ending_Date: 09-Jun-2021
    Currentness_Reference:
    ground condition at time data were collected.
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: GeoTIFF
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Raster data set.
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 10
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -123.00000
      Latitude_of_Projection_Origin: 0.00000
      False_Easting: 500000.0
      False_Northing: 0.00
      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.5
      Ordinates (y-coordinates) are specified to the nearest 0.5
      Planar coordinates are specified in Meters
      The horizontal datum used is North American Datum of 1983, 2011 realization (NAD83(2011)).
      The ellipsoid used is GRS80.
      The semi-major axis of the ellipsoid used is 6378137.00.
      The flattening of the ellipsoid used is 1/298.257222101.
      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: North America Vertical Datum 1988
      Altitude_Resolution: 0.1
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method:
      Explicit elevation coordinate included with horizontal coordinates
  7. How does the data set describe geographic features?
    GeoTiff
    elevation in meters relative to NAVD88 (Source: Producer defined)
    N/A
    Elevation relative to the North American vertical datum of 1988 (NAVD88). Grid cells containing no information were assigned a fill value of -3.40282e+30. (Source: Producer defined)
    Range of values
    Minimum:-20.9
    Maximum:2.4
    Units:meters
    N/A
    Relative seafloor backscatter intensity. NaN = not a number because no backscatter data are available at this location in the raster grid. (Source: Producer defined)
    Range of values
    Minimum:0
    Maximum:1
    Entity_and_Attribute_Overview:
    Bathymetric and seafloor backscatter intensity data in raster format.
    Entity_and_Attribute_Detail_Citation: U.S. Geological Survey field activity 2021-621-FA

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Peter Dartnell
    • Andrew W. Stevens
    • Gerald A. Hatcher
    • Peter Dal Ferro
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    Attn: PCMSC Science Data Coordinator
    2885 Mission Street
    Santa Cruz, CA

    831-427-4747 (voice)
    pcmsc_data@usgs.gov

Why was the data set created?

Growth of subaqueous sand dunes commonly causes shoaling in engineered river channels that necessitates costly dredging to maintain adequate depths for navigation. The factors that result in sand wave growth are theoretically understood from laboratory experiments, but the capacity to predict sand wave geometries in field settings is limited due to temporal and spatial variability in hydrodynamics and sediment grain size. Detailed measurements of sand wave geometries, hydrodynamics, and grain size are therefore needed to test and improve numerical models and inform efficient management strategies in navigation channels. This data release presents surface sediment grain size distributions, bathymetry and seafloor acoustic backscatter, and water velocity data acquired at four sites with subaqueous sand dunes in the lower Columbia River, Washington and Oregon, between June 4 and June 9, 2021. The four sites were located between 65 km and 127 km upstream from the ocean inlet along a gradient of relative tidal and fluvial influence. The survey was performed during peak annual river discharge when sediment transport processes were likely active. High resolution digital images were collected at each site with an underwater camera system that was repeatedly lowered to the seabed along a series of 1 km-long transects oriented along the main navigation channel and spaced about 60 m apart. The grain size distributions of the seabed images were estimated using an automated image processing technique and tested with observed grain size distributions derived from manual measurements on a subset of 16 images. Swath bathymetry and seafloor acoustic backscatter data were collected repeatedly at each site using a 234.5 kHz phase-differencing sidescan sonar to characterize sand wave geometry and bathymetric change resulting from sand wave migration. Current velocity data were collected from an underway survey vessel equipped with a downward looking 600 kHz ADCP along transects oriented both along- and across the main navigation channel. Combined, these data provide a comprehensive characterization of mobile subaqueous sand dunes that can be used to improve predictions of dune growth in complicated field settings and inform efficient sediment management practices in the lower Columbia River.

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
    Date: 2023 (process 1 of 1)
    The data were collected with a SWATHplus-M 234-kHz interferometric side-scan sonar system pole-mounted on the U.S. Geological Survey (USGS) R/V Parke Snavely. During the mapping mission, an Applanix POS-MV (Position and Orientation System for Marine Vessels) was used to position the vessel during data collection, and it also accounted for vessel motion such as heave, pitch, and roll. The POS-MV also recorded position and vessel motion parameters for later post-processing. Sound-velocity profiles were collected throughout the survey days with a Castaway sound velocimeter. Post-processed POS-MV Smoothed Best Estimate of Trajectory (SBET) files were merged with the survey line files using BathySwath software and then the line files were imported into SonarWiz software. Soundings were cleaned for obvious errors and data from each site were gridded into continuous surfaces with resolutions of 0.5 and 1 m for the bathymetric and seafloor acoustic backscatter data, respectively. The base surface was exported as a GeoTiff file in UTM Zone 10, NAD83 (2011) coordinates vertically referenced to the North American Vertical Datum of 1988 (NAVD88) based on National Geodetic Survey Geoid18 offsets.
  3. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    The SWATHPlus sonar systems depth accuracy reduces with horizontal range. The system has an estimated vertical depth uncertainty ranging from about 0.05 m to 0.34 m over a horizontal range of 0 to 90 m (http://www.bathyswath.com/sites/default/files/documents/ETD_2002_Bathyswath%20information_EN.pdf). Accuracies of final products may be lower due to total propagated uncertainties of the mapping systems, which include sonar system, position and motion compensation system, and navigation, as well as data processing that includes sounding cleaning, gridding, and datum transformations.
  2. How accurate are the geographic locations?
    The Applanix POS-MV post-processed horizontal positional accuracy is about 0.1 m with roll and pitch accuracies of about 0.02 degrees (https://www.applanix.com/downloads/products/specs/posmv/POS-MV-WaveMaster-II.pdf). The SWATHPlus sonar system with 234 kHz transducer has an across track resolution of about 5 cm (http://www.bathyswath.com/sites/default/files/documents/ETD_2002_Bathyswath%20information_EN.pdf). Accuracies of final products may be lower due to total propagated uncertainties of the mapping systems, which include sonar system, position and motion compensation system, and navigation, as well as data processing that includes sounding cleaning, gridding, and datum transformations. A standard deviation grid calculated from the bathymetry data is included in the data release.
  3. How accurate are the heights or depths?
    The Applanix POS-MV post-processed vertical positional accuracy is about 0.2 m (https://www.applanix.com/downloads/products/specs/posmv/POS-MV-WaveMaster-II.pdf). The SWATHPlus sonar system with 234 kHz transducer has a measurement resolution limit of about 0.6 cm and a resolution detection limit of about 3 mm (http://www.bathyswath.com/sites/default/files/documents/ETD_2002_Bathyswath%20information_EN.pdf). Accuracies of final products may be lower due to total propagated uncertainties of the mapping systems, which include sonar system, position and motion compensation system, and navigation, as well as data processing that includes sounding cleaning, gridding, and datum transformations.
  4. Where are the gaps in the data? What is missing?
    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.
  5. How consistent are the relationships among the observations, including topology?
    No formal logical accuracy tests were conducted

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints None
Use_Constraints 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 originators of the dataset and in products derived from these data. This information is not intended for navigation purposes.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey - CMGDS
    2885 Mission Street
    Santa Cruz, CA

    831-427-4747 (voice)
    pcmsc_data@usgs.gov
  2. What's the catalog number I need to order this data set? Downloadable data in GeoTiff format and compressed into zipped archives. Files were grouped by data type; bathymetry- lcr21_bathy.zip, and seafloor acoustic backscatter- lcr21_backscatter.zip. Individual files within the ZIP archives were named according to the following convention: XXX_YYYYMMDD_Thhmmss_datatype.tif, where XXX denotes the site surveyed; SKM- Skamokawa, SLG - Slaughters Bar, LDB - Lower Dobelbower, WLW - Willow Bar, YYYYMMDD provides the start date of the survey, hhmmss, denotes the start time of the survey, and datatype is either bathy (for bathymetry data) or backscatter (for seafloor acoustic backscatter data). Additional details about the files contained in each zip archive and start and end times of each survey are provided in the Support File, swath_survey_dates_times.csv.
  3. What legal disclaimers am I supposed to read?
    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.
  4. How can I download or order the data?
    • Availability in digital form:
      Data format: Downloadable zip file contains the TIFF (.tif) version of the seafloor acoustic backscatter data. in format GeoTIFF (version ArcMap (version 10.3.1)) Size: 10.5
      Network links: https://doi.org/10.5066/P92U1KPY
      Data format: Downloadable zip file contains the TIFF (.tif) version of the bathymetric data. in format GeoTIFF (version ArcMap (version 10.3.1)) Size: 43.4
      Network links: https://doi.org/10.5066/P92U1KPY
    • Cost to order the data: None.

  5. What hardware or software do I need in order to use the data set?
    The downloadable data file has been compressed with the "zip" command and can be unzipped with Winzip (or other tool) on Windows systems. To utilize these data, the user must have software capable of uncompressing the WinZip file and importing and viewing a GeoTIFF file.

Who wrote the metadata?

Dates:
Last modified: 08-Aug-2023
Metadata author:
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Attn: PCMSC Science Data Coordinator
2885 Mission Street
Santa Cruz, CA

831-427-4747 (voice)
pcmsc_data@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/pcmsc/DataReleases/CMGDS_DR_tool/DR_P92U1KPY/lcr21_bathy_backscatter_metadata.faq.html>
Generated by mp version 2.9.51 on Fri Aug 18 09:04:49 2023