Legend (pg_wbd/pg_huc_reference_prod)

2-digit HU (Region) (1) 4-digit HU (Subregion) (2) 6-digit HU (Basin) (3) 8-digit HU (Subbasin) (4) 10-digit HU (Watershed) (5) 12-digit HU (Subwatershed) (6) 14-digit HU (7) 16-digit HU (8)