Note: The 12-digit Watershed Boundary Dataset (WBD) replaces the 14-digit layer. It is a revised and enhanced 14-digit dataset. Changes occurring between the 14 and 12-digit versions include the following:
Numeric coding in the new version added 2 digits to specify each smaller (finer) watershed delineation, rather than 3 digits. e.g. 8-digit subbasins were subdivided into 10-digit watersheds and 10-digit watersheds were subdivided into 12-digit subwatersheds rather than the former 8, 11 and 14-digit sequence.
To provide more consistency in size of subwatershed, some 14-digit subwatersheds were aggregated for the 12-digit layer. (No change in size or boundary occurred changing between the 11-digit and 10-digit portions of the WBD.)
The coding scheme was revised to provide more consistency across state boundaries.
Boundary delineations found to be in error were corrected.