WA Bathymetry CoNED MLLW [Washington (State)]
WaTech Geospatial Program Office · 2025 Full Details
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Full Details
- Title
- WA Bathymetry CoNED MLLW [Washington (State)]
- Description
- For the purposes of research and monitoring in marine environments, elevation data is typically most useful when it is expressed relative to tidal rather than orthometric vertical datums. For example, the potential habitat depth of submerged aquatic vegetation is often expressed as a range relative to mean lower low water (MLLW), representing the specific light requirements of each species. This MLLW bathymetric model (elevation values in meters) of the southern Salish Sea is based on the USGS CoNED topobathymetric digital elevation models of Puget Sound (OCM Partners, 2022a) and the Strait of Juan de Fuca (OCM Partners, 2022b), converted from NAVD88 to MLLW using NOAA's VDatum 4.6.1 transformation grids (Office of Coast Survey, 2023), and projected onto NAD 1983 HARN StatePlane Washington South FIPS 4602. For more information, contact Tyler Cowdrey, WA DNR, Nearshore Habitat Program at: tyler.cowdrey@dnr.wa.gov or nearshore@dnr.wa.gov. Suggested citation: Cowdrey, T. (2024). Washington State USGS CoNED MLLW Bathymetric DEM [Data Set]. Washington State Department of Natural Resources, Nearshore Habitat Program. [https://gis.dnr.wa.gov/image/rest/services/Aquatics/WA_bathymetry_CoNED_MLLW/ImageServer]. The values of MLLW in this model were generated using source and intermediate data products with significant interpolation and are intended for informational and research purposes only. This product has not been reviewed by a licensed surveyor and should not be used in place of professional surveys for the assessment of tideland parcel boundaries. This product should not be used for navigation. WA DNR makes no warranties about the accuracy of this product. Rough processing workflow: CoNED tiles were bulk downloaded in GeoTIFF format from NOAA Digital Coast (https://coast.noaa.gov/htdata/raster2/elevation/). VDatum 4.6.1 was used to generate NAVD88 to MLLW transformation grids at a resolution of ~0.0002 degrees in ITRF14, which were were then combined and projected onto NAD 1983 (2011) UTM 10N and resampled at 1 meter resolution (snapped to CoNED) using bilinear interpolation. The combined grid was then used to batch transform CoNED tiles from NAVD88 to MLLW using ArcPy maintaining extent, PCS, cell size and snap raster. The new CoNED MLLW tiles were mosaicked and projected onto NAD 1983 HARN StatePlane Washington South FIPS 4602 (SPWAS) as a continuous raster to prevent tile discontinuities. Finally, the continuous CoNED MLLW SPWAS raster was re-tiled, tiles were named by row and column, and pixel values above 10 meters of elevation were removed to improve the reliability of the final product for marine applications. References: OCM Partners. 2022a. 1887 - 2017 USGS CoNED Topobathy DEM (Compiled 2020): Puget Sound, WA. NOAA National Centers for Environmental Information. https://www.fisheries.noaa.gov/inport/item/59971 . OCM Partners. 2022b. 1891 - 2016 USGS CoNED Topobathy DEM (Compiled 2021): Strait of Juan de Fuca, WA. NOAA National Centers for Environmental Information. https://www.fisheries.noaa.gov/inport/item/65169 . Office of Coast Survey, N.O.A.A., U.S. Department of Commerce. 2023. Vertical Datum Transformation (VDatum 4.6.1). https://vdatum.noaa.gov/download.php .
- Creator
- Washington State Department of Natural Resources
- Publisher
- WaTech Geospatial Program Office
- Temporal Coverage
- Last Modified: 2025-10-06
- Date Issued
- 2025-10-06
- Rights
- The Washington State Department of Natural Resources (DNR) provides these geographic data "as is." DNR makes no guarantee or warranty concerning the accuracy of information contained in the geographic data. DNR further makes no warranties, either expressed or implied as to any other matter whatsoever, including, without limitation, the condition of the product, or its fitness for any particular purpose. The burden for determining fitness for use lies entirely with the user. Although these data have been processed successfully on computers of DNR, no warranty, expressed or implied, is made by DNR regarding the use of these data on any other system, nor does the fact of distribution constitute or imply any such warranty. In no event shall the DNR have any liability whatsoever for payment of any consequential, incidental, indirect, special, or tort damages of any kind, including, but not limited to, any loss of profits arising out of use of or reliance on the geographic data or arising out of the delivery, installation, operation, or support by DNR.
- Access Rights
- Public
- Format
- ArcGIS ImageMapLayer
- Language
- English
- Date Added
- October 06, 2025
- Provenance Statement
- The metadata for this resource was last retrieved from State of Washington Geospatial Open Data Portal on 2025-11-04.
Resource Class
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Cite and Reference
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Citation
Washington State Department of Natural Resources (2025). WA Bathymetry CoNED MLLW [Washington (State)]. WaTech Geospatial Program Office. https://geo.wa.gov/datasets/wadnr::wa-bathymetry-coned-mllw (web service) -
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