Savannah River, GA/SC (S120) Bathymetric Digital ElevationModel (30 meter resolution) Derived From Source Hydrographic SurveySoundings Collected by NOAA

Bathymetry for the Savannah River was derived from nine surveys containing34,353 soundings. Two older, overlapping, less accurate surveys wereomitted before tinning the data. The average separation between soundingswas 59 meters. Seven of the nine surveys used dated from 1934. Theremaining two surveys, located in the southeast, dated from 1971 and 1974.The total range of sounding data was 1.2 meters to -15.9 meters at mean lowwater. Mean high water values between 1.9 and 2.5 meters were assigned to theshoreline. Three points were found that were not consistent with the surroundingdata. These were removed prior to tinning. DEM grid values outside theshoreline (on land) were assigned null values (-32676).The Savannah River has seven 7.5 minute DEMs and two one degree DEMs.The 1 degree DEMs were generated from the higher resolution 7.5minute DEMs which covered the estuary. A Digital Elevation Model(DEM) contains a series of elevations ordered from south to northwith the order of the columns from west to east. The DEM isformatted as one ASCII header record (A- record), followed by aseries of profile records (B- records) each of which include a shortB-record header followed by a series of ASCII integer elevations(typically in units of 1 centimeter) per each profile. The lastphysical record of the DEM is an accuracy record (C-record).The 7.5-minute DEM (30- by 30-m data spacing) is cast on theUniversal Transverse Mercator (UTM) projection. It provides coveragein 7.5- by 7.5-minute blocks. Each product provides the samecoverage as a standard USGS 7.5-minute quadrangle but the DEMcontains over edge data. Coverage is available for many estuaries ofthe contiguous United States but is not complete.