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Estuarine Bathymetric Digital Elevation Models

The National Ocean Service (NOS) Estuarine Bathymetric Digital Elevation Models are gridded bathymetry datasets interpolated from 150 years’ worth of hydrographic survey data collected by the former NOS Special Projects Office. The initiative produced datasets for 70 estuaries in the conterminous United States with sufficient data coverage to support detailed bathymetric processing.

Hydrographic survey sample

Specifications and File Structure

Estuarine bathymetric data are available as gridded products with 30 meter spatial resolution. The extent shapefile, visualization files, and density images are packaged together, while the DEM is available as a stand-alone download.

Note: Do not use bathymetric data for navigation. Refer to NOAA nautical charts, and NOS source data to navigate in U.S. coastal waters.

Estuarine Bathymetric Digital Elevation Models
Name / Location Bathymetric DEM Data Metadata
Albemarle Sound Access NetCDF (.nc) XML
Altamaha River Access NetCDF (.nc) XML
Apalachicola Bay Access NetCDF (.nc) XML
Aransas Bay Access NetCDF (.nc) XML
Atchafalaya Bay Access NetCDF (.nc) XML
Baffin Bay Access NetCDF (.nc) XML
Bar Harbor Access NetCDF (.nc) XML
Barataria Bay Access NetCDF (.nc) XML
Barnegat Bay Access NetCDF (.nc) XML
Biscayne Bay Access NetCDF (.nc) XML
Bogue Sound Access NetCDF (.nc) XML
Broad River Access NetCDF (.nc) XML
Buzzards Bay Access NetCDF (.nc) XML
Calcasieu Lake Access NetCDF (.nc) XML
Cape Cod Bay Access NetCDF (.nc) XML
Cape Fear River Access NetCDF (.nc) XML
Casco Bay Access NetCDF (.nc) XML
Charleston Harbor Access NetCDF (.nc) XML
Charlotte Harbor Access NetCDF (.nc) XML
Chesapeake Bay Access NetCDF (.nc) XML
Choctawhatchee Bay Access NetCDF (.nc) XML
Columbia River Access NetCDF (.nc) XML
Corpus Christi Bay Access NetCDF (.nc) XML
Delaware Bay Access NetCDF (.nc) XML
Galveston Bay Access NetCDF (.nc) XML
Gardiners Bay Access NetCDF (.nc) XML
Grays Harbor Access NetCDF (.nc) XML
Great Bay Access NetCDF (.nc) XML
Great South Bay Access NetCDF (.nc) XML
Hudson River Access NetCDF (.nc) XML
Indian River Access NetCDF (.nc) XML
Long Island Sound Access NetCDF (.nc) XML
Massachusetts Bay Access NetCDF (.nc) XML
Matagorda Bay Access NetCDF (.nc) XML
Mississippi Sound Access NetCDF (.nc) XML
Mobile Bay Access NetCDF (.nc) XML
Monterey Bay Access NetCDF (.nc) XML
Muscongus Bay Access NetCDF (.nc) XML
Narragansett Bay Access NetCDF (.nc) XML
New Jersey Inland Bays Access NetCDF (.nc) XML
Ossabaw Sound Access NetCDF (.nc) XML
Pamlico Sound Access NetCDF (.nc) XML
Penobscot Bay Access NetCDF (.nc) XML
Pensacola Bay Access NetCDF (.nc) XML
Perdido Bay Access NetCDF (.nc) XML
Puget Sound Access NetCDF (.nc) XML
Raritan Bay Access NetCDF (.nc) XML
Saco Bay Access NetCDF (.nc) XML
San Antonio Bay Access NetCDF (.nc) XML
San Diego Bay Access NetCDF (.nc) XML
San Francisco Bay Access NetCDF (.nc) XML
San Pedro Bay Access NetCDF (.nc) XML
Santa Monica Bay Access NetCDF (.nc) XML
Santee River Access NetCDF (.nc) XML
Sarasota Bay Access NetCDF (.nc) XML
Savannah River Access NetCDF (.nc) XML
Sheepscot Bay Access NetCDF (.nc) XML
Southern Florida Access NetCDF (.nc) XML
St. Andrew Bay Access NetCDF (.nc) XML
St. Andrew/St. Simons Sound Access NetCDF (.nc) XML
St. Catherines/Sapelo Sound Access NetCDF (.nc) XML
St. Helena Sound Access NetCDF (.nc) XML
St. Johns River Access NetCDF (.nc) XML
St. Marys River/Cumberland Sound Access NetCDF (.nc) XML
Tampa Bay Access NetCDF (.nc) XML
Terrebonne/Timbalier Bay Access NetCDF (.nc) XML
Tomales Bay Access NetCDF (.nc) XML
Umpqua River Access NetCDF (.nc) XML
Willapa Bay Access NetCDF (.nc) XML
Winyah Bay Access NetCDF (.nc) XML
Yaquina Bay Access NetCDF (.nc) XML

Contact

dem.info@noaa.gov

Use Cases

Bathymetric data adds another dimension to geographic mapping and modeling, and can be used as either a background layer or 3D surface for draping thematic maps such as benthic or marine organism habitats and geologic data. It also delineates the lower boundary of the water column in hydrodynamic models used to monitor and predict the movement of oil and hazardous materials, temperature and salinity distributions, animal migration patterns, and model storm surge and tsunami effects.

Data Characteristics

The perimeter of each bathymetry aligns with estuarine drainage area water boundaries determined by the NOS Coastal Assessment Framework. Elevations do not extend beyond the high water line. Bathymetric depths are vertically referenced to the local tidal datum, typically Mean Lowest Low Water (MLLW) averaged over a 19 year tidal epoch. There are no plans to produce bathymetries for other estuaries, but some existing bathymetries are updated as part of Coastal Digital Elevation Models, which can accessed through the Bathymetric Data Viewer application.

Frequently Asked Questions

What is the source data for the bathymetry?
Consult the metadata for each estuary to view source data.
How do you view data in GIS applications?
NetCDF data can be opened in a variety of GIS software packages, including ESRI ArcGIS. Alternatively, users can convert from netCDF to other common raster formats using Geospatial Data Abstraction Library utilities to facilitate use in a GIS environment.
Why do sections of some estuaries appear ramped or have a constant slope?
The constant slope may be real or an artifact of sampling density. Very few estuaries have a constant sounding density over the entire area of the estuary. Some estuaries have larger gaps in data than others, and the density of the original soundings often change from one section of the estuary to another. A triangulation process is used to produce the gridded data. Areas with dense concentrations of soundings will produce more accurate grid values than areas where the soundings are sparse. Some areas have gaps of many hundreds of meters. These areas will show interpolation across large distances which will appear evenly spaced. In order to determine where these areas are, the user can download the Sounding Coverage Images, which are included in the supplemental information zipfile for each DEM. These images allow the user to get a general idea of the distance between the original soundings data so that they may assess for themselves whether or not the original point coverages meet their project's resolution needs.