Potomac River Pilot Topobathymetric Digital Elevation Model, 1979 to 2025

The U.S. Geological Survey (USGS) 3D Elevation Program (3DEP) has developed an integrated 1-meter topobathymetric digital elevation model (TBDEM) for the Potomac River extending from tidal Washington, D.C. to upstream of Hancock, Maryland. This is the third 3DEP pilot inland TBDEM, developed to produce a 3-dimensional surface elevation model that integrates topographic bare-earth elevation surfaces with river channel bed topobathymetry and estuarine bathymetry. Integration of inland bathymetry and bare-earth elevation data into seamless topobathymetric models advances the USGS 3D National Topography Model (3DNTM) goal to integrate elevation and hydrography data from the next generation of the 3DEP and the 3D Hydrography Program. The pilot project area of interest includes reaches of the Potomac River, Anacostia River, Shenandoah River, Tidal Basin, and Pentagon Lagoon hydrographic features. The integrated TBDEM will provide a fundamental geospatial baseline to support enhanced 2D/3D hydrologic modeling, fisheries habitat restoration, and hazardous spill / drinking water supply modeling, and other key science applications such as flood plain analyses and fluvial geomorphic feature mapping. This pilot inland topobathy product supports the Interstate Commission on the Potomac River Basin (ICPRB) work to improve flow modeling for resource management and hazardous spill modeling to help protect drinking water supplies and quality in the District of Columbia. The Potomac River TBDEM renders spatial integration of 19 different geospatial elevation data sources. Topographic lidar data are from USGS 3DEP, Maryland Geographic Information Office, Federal Emergency Management Agency (FEMA) VAWVMD- Region 3, and Washinton D.C. Office of the Chief Technology Officer (OCTO). Acoustic bathymetry data for the Potomac and Anacostia Rivers are from District of Columbia Department of Energy and Environment (DOEE) and the U.S. Army Corps of Engineers. Nearshore to offshore bathymetry data are from the National Oceanic and Atmospheric Administration (NOAA), National Centers for Environmental Information (NCEI) and USGS Coastal National Elevation Database (CoNED). Topobathymetric lidar for Potomac River is from USGS 3DEP and collaborative partners. The bank-to-bank bathymetry coverage from the 2019/2021 USGS topobathymetic lidar acquisitions yielded an 85.5% mapping of the submerged topography. Acoustic doppler current profiler bathymetry for reservoirs behind lowhead dams #4/#5 on the Potomac River was provided by the USGS Maryland/Delaware/DC and Virginia / West Virginia Water Science Centers. Geospatial data for the TBDEM were integrated where the best available topography, topobathymetry, and bathymetry elevation data are sorted and prioritized based on survey date, accuracy, spatial distribution, and point density. The output TBDEM is horizontally referenced to UTM Zone 18 N, NAD83 2011 and vertically referenced to the North American Vertical Datum of 1988 (NAVD88) Geoid18. The spatial resolution is 1 meter with general elevations ranging from 630 meters on land to -31.48 meters (submerged). The overall temporal range of the input topography, topobathymetry, and bathymetry is 1979 to 2025. The project is funded by the USGS National Geospatial Program.