Skip to main content
U.S. flag

An official website of the United States government

Topobathymetric Model of the Coastal Carolinas, 1851 to 2020

March 17, 2022

To support Hurricane Florence impact modeling of storm-induced flooding and sediment transport, the U.S. Geological Survey (USGS) Coastal National Elevation Database (CoNED) Applications Project has created an integrated 1-meter topobathymetric digital elevation model (TBDEM) for coastal North Carolina, and South Carolina. High-resolution coastal topobathymetric data are required to characterize flooding, storms, and sea-level rise inundation hazard zones and other earth science applications, such as the development of sediment transport and storm surge models. This TBDEM consists of the best available multi-source topographic and bathymetric elevation data for the Coastal Carolinas including neighboring bays, estuaries, waterways, inlets, and islands. The Coastal Carolinas TBDEM integrates 28 different data sources including topographic and bathymetric data, such as lidar point clouds and multi-beam acoustic surveys obtained from USGS, the National Oceanic and Atmospheric Administration, the U.S. Army Corps of Engineers, South Carolina Lidar Consortium, and the South Carolina Department of Natural Resources. The topographic and bathymetric surveys were sorted and prioritized based on survey date, accuracy, spatial distribution, and point density to develop a model based on the best available elevation and bathymetric data. Because bathymetric data are typically referenced to tidal datums, such as Mean High Water or Mean Low Water, all tidally referenced heights were transformed into orthometric heights based on the GEOID12B geoid, which is normally used for mapping elevation on land using the North American Vertical Datum of 1988. The spatial horizontal resolution is 1-meter with the general location ranging from the Virginia/North Carolina border to the South Carolina/Georgia border in the south and extending offshore past Cape Hatteras. The overall temporal range of the input topography and bathymetry is 1851 to 2020 with a maximum depth extending to 66 meters. The topography surveys are from 1999-2020. The bathymetry surveys were acquired between 1851 and 2020.This data release was funded by the Additional Supplemental Appropriations for Disaster Relief Act of 2019 (H.R. 2157) for North Carolina and South Carolina.