Procedures_Used: This coverage contains the 8 digit hydrologic unit boundaries for Alaska. The coverage was downloaded by Iowa State University from USGS (<http://water.usgs.gov/lookup/getspatial?huc250k>). NRCS clipped the coverage to a shoreline created by the National Center for Resource Innovations (NCRI). NCRI derived the shoreline from 1:2,000,000 scale USGS Digital Line Graph (DLG) files
Revisions: This coverage was last updated in 2000.
Reviews_Applied_to_Data: This coverage has received no formal review, although it has been widely used by NRCS since 2000 and any serious errors would have been obvious.
Related_Spatial_and_Tabular_Data_Sets: Other State of the Land basemap coverages include counties and Federal lands, derived from USGS coverages, and a Major Land Resource Areas (MLRA) coverage derived from the MLRA map in Agricultural Handbook 296. These are intended to have the same shoreline and outer boundaries, although this has not been thoroughly verified.
References_Cited: NRCS National Headquarters Resource Assessment Division.
for metadata for entire HUC process see <http://water.usgs.gov/GIS/metadata/usgswrd/huc250k.html>