Gerald A. Hatcher Andrew W. Stevens Peter Dal Ferro 20230808 comma-delimited text data release DOI:10.5066/10.5066/P92U1KPY Pacific Coastal and Marine Science Center, Santa Cruz, California U.S. Geological Survey https://doi.org/10.5066/P92U1KPY Andrew W. Stevens Gerald A. Hatcher Peter Dal Ferro Peter Dartnell Jonathan A. Warrick Nicholas Cohn Hans R. Moritz 2023 data release DOI:10.5066/P92U1KPY Pacific Coastal and Marine Science Center, Santa Cruz, CA U.S. Geological Survey 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. https://doi.org/10.5066/P92U1KPY In situ seafloor images were acquired at four sites (SKM, SLG, LDB, WLW) in the lower Columbia River, Washington and Oregon, with an underwater camera system between June 5 and June 8, 2021. Between 248 and 427 digital images of the sediment surface 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 camera consisted of a FLIR Blackfly BFS-PGE-50S5 camera and 50 mm lens in a waterproof housing that resulted in a field of view of approximately 17 mm and a resolution of 0.00657 mm per pixel when the housing window was flush with the sediment surface. The imagery is provided in .tif format and compressed into .zip archives for each site. Images used for calibration of the automated processing algorithm to determine sediment grain size distributions were different than those used to validate the technique and were provided in separate .zip archives. 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. Additional information about the field activity or activities 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. 20210605 20210608 ground condition at time data were collected Complete None planned -123.442574 -122.762951 46.250242 45.712673 USGS Metadata Identifier USGS:683b0b15-bdf4-45a1-88b1-82af467d8672 ISO 19115 Topic Category geoscientificInformation Data Categories for Marine Planning Substrate USGS Thesaurus ocean processes sediment transport grain-size analysis Marine Realms Information Bank (MRIB) keywords sediment Global Positioning System (GPS) observations None U.S. Geological Survey USGS Coastal and Marine Hazards and Resources Program CMHRP Pacific Coastal and Marine Science Center PCMSC Geographic Names Information System (GNIS) Columbia River State of Washington State of Oregon 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. U.S. Geological Survey, Pacific Coastal and Marine Science Center PCMSC Science Data Coordinator mailing and physical

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Santa Cruz CA 95060 831-427-4747 pcmsc_data@usgs.gov eyeball_field_data.png Photographs showing equipment used to acquire seafloor images and example images collected with the camera system PNG MATLAB Version: 9.13.0.2080170 (R2022b) Update 1 Information about the acquisition times and positions is recorded to the image metadata (EXIF) header for each image. The positions of the images were determined using an Applanix POSMV Wavemaster operating in DGNSS mode. A shipboard computer running a custom software was used to view and record images from the camera and record the positions from the POSMV resulting in a log file that contained the image file name, acquisition time, and position of the survey vessel at the time of image acquisition. The positions and times in the log file were later written to the EXIF header of each image using the command-line 'exiftool' software. The positions stored in the EXIF are in the WGS84 (G1150) coordinate reference system and times are all in Coordinated Universal Time (UTC). No formal logical accuracy tests were conducted. 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. The locations of each seafloor image collected were determined using an Applanix POSMV Wavemaster operating in DGNSS mode. Manufacturer reported accuracy of the horizontal positions while operating in DGNSS mode is between 0.5 and 2 m depending on the quality of the DGNSS corrections received (https://www.applanix.com/downloads/products/specs/posmv/POS-MV-WaveMaster-II.pdf). Additional uncertainty in the horizontal positions of the images due to instrument layback, or non-vertical wire angle between surface vessel and camera at the seafloor, is unknown but assumed to be minimal because of the weight of the camera and slow speed of the vessel relative to the ambient currents during image acquisition. High resolution spatial surveys were performed between June 5 and 8, 2021 to quantify surface sediment grain size distributions of mobile subaqueous dunes at four sites in the lower Columbia River, Washington and Oregon. At each site, digital images of the sediment surface were collected 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 camera consisted of a FLIR Blackfly BFS-PGE-50S5 camera and 50 mm lens in a waterproof housing that resulted in a field of view of approximately 17 mm and a resolution of 0.00657 mm per pixel when the housing window was flush with the sediment surface. An ethernet cable between the survey vessel and camera provided power to the camera and allowed for real-time viewing of the seafloor imagery on a computer during acquisition. The locations of each seafloor image were determined using an Applanix POSMV Wavemaster global navigation satellite system receiver operating in DGNSS mode. 20210608 Imagery were inspected to remove images that were not suitable for analysis, including blurry images and replicate images. Clear images of the seabed were subjectively classified into three groups including those that were suitable for automated grain size analysis, those that were too coarse (too few grains in the image), and those that were too fine (individual grains not visible) for analysis. The images that were too coarse or too fine for detailed quantitative analysis were retained for the qualitative information contained. 20221213 Images were organized by site zipped for distribution. The sites include Skamokawa (dgs_images_slg.zip), Slaughters Bar (dgs_images_skm.zip), Lower Dobelbower (dgs_images_ldb.zip), and Willow Bar (dgs_images_wlw.zip). Additional zip files are provided that include the images used for calibration (dgs_images_calibration.zip) and validation (dgs_images_validation.zip) of the automated image processing techniques to quantify grain size distributions in the imagery. 20230315 Raster Pixel 2048 2448 0.000001 0.000001 Decimal degrees WGS_1984 WGS_1984 6378137.0 298.257223563 There are no additional attributes besides the tags described in data quality section associated with these images. USGS Field Activity 2021-621-FA U.S. Geological Survey - CMGDS mailing and physical

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Santa Cruz CA 95060 1-831-427-4747 pcmsc_data@usgs.gov The seafloor images from four sites conducted during the survey are available in TIFF format. The images from each site (SKM, SLG, LDB, WLW) as well as images used for calibration and validation of the automated processing technique used to determine the sediment grain size distributions of each image are combined into a zip file with the site identifier in the file name. 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. TIFF MATLAB Version: 9.13.0.2080170 (R2022b) Zipped files contain geotagged seafloor images collected for calibration of the image processing technique. WinZip, 7zip, Peazip or pkUnzip 198.3 https://doi.org/10.5066/P92U1KPY Data and metadata can be downloaded using the Network_Resource_Name link and scrolling down to the Other Imagery section. TIFF MATLAB Version: 9.13.0.2080170 (R2022b) Zipped files contain geotagged seafloor images collected from the Lower Dobelbower (LDB) site. WinZip, 7zip, Peazip or pkUnzip 4400.0 https://doi.org/10.5066/P92U1KPY Data and metadata can be downloaded using the Network_Resource_Name link and scrolling down to the Other Imagery section. TIFF MATLAB Version: 9.13.0.2080170 (R2022b) Zipped files contain geotagged seafloor images collected from the Skamokawa (SKM) site. WinZip, 7zip, Peazip or pkUnzip 4600.0 https://doi.org/10.5066/P92U1KPY Data and metadata can be downloaded using the Network_Resource_Name link and scrolling down to the Other Imagery section. TIFF MATLAB Version: 9.13.0.2080170 (R2022b) Zipped files contain geotagged seafloor images collected from the Slaughters Bar (SLG) site. WinZip, 7zip, Peazip or pkUnzip 3200.0 https://doi.org/10.5066/P92U1KPY Data and metadata can be downloaded using the Network_Resource_Name link and scrolling down to the Other Imagery section. TIFF MATLAB Version: 9.13.0.2080170 (R2022b) Zipped files contain geotagged seafloor images collected for validation of the image processing technique. WinZip, 7zip, Peazip or pkUnzip 199.0 https://doi.org/10.5066/P92U1KPY Data and metadata can be downloaded using the Network_Resource_Name link and scrolling down to the Other Imagery section. TIFF MATLAB Version: 9.13.0.2080170 (R2022b) Zipped files contain geotagged seafloor images collected from the Willow Bar (WLW) site. WinZip, 7zip, Peazip or pkUnzip 5400.0 https://doi.org/10.5066/P92U1KPY Data and metadata can be downloaded using the Network_Resource_Name link and scrolling down to the Other Imagery section. None. 20230808 U.S. Geological Survey, Pacific Coastal and Marine Science Center PCMSC Science Data Coordinator mailing and physical

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Santa Cruz CA 95060 831-427-4747 pcmsc_data@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998