Classified polygons covering the Columbia River estuary were derived from the U.S. Coast & Geodetic Survey historic topographic survey maps (T-sheets) from 1868 to 1901. Hydrographic sheets (H-sheets) provided bathymetric depth values which were converted into a DEM. These products are provided in an ArcGIS personal geodatabase.
Download T-sheets (classified landcover)
Download T-sheets (georeferenced images)
Comparison of the historic bathymetry of the Columbia River estuary (derived from hydrographic sheets) to the current bathymetry. This comparison demonstrates the effect of navigational dredging of the mainstem channel, which has produced a much more uniform, connected thalweg throughout the entire estuary.