Revisions: This is version one. Reviews_Applied_to_Data: Data reviewed by Chester Novak, Kirk Appleman (Salem BLM); Barb Ellis-Sugai (USFS-SNF); Mary D'Aversa (Eugene BLM); Dan Carpenter, Lance Finnegan (Coos Bay BLM); Rick Momsen, Lowell Duell (Roseburg BLM); and Sharon Clarke, Alissa Moses (OSU),
References: USGS GIS Weasel (<http://wwwbrr.cr.usgs.gov/weasel/>) 10m Drainage Enforced Digital Elevation Models (DE-DEM) (<http://www.reo.gov/dem/ore>) (<http://www.averstar.com/news/dedem.html>) Coastal Landscape Analysis and Modeling Study (CLAMS) (<http://www.fsl.orst.edu/clams/>) Fifth field HUC (<http://www.sscgis.state.or.us/data/themes.html>) Digital Raster Graphics (DRG) (<http://mcmcweb.er.usgs.gov/drg/>) 1:24,000 Hydrology Digital Line Graphs (DLG) (<http://edcwww.cr.usgs.gov/doc/edchome/ndcdb/ndcdb.html>) USFS Interagency Guideline on Delineation of Watershed and Subwatershed Hydrologic Unit Boundaries (<http://wwwga.usgs.gov/gis/iag.html>) Mapping and Digitizing Watershed and Subwatershed Hydrologic Unit Boundaries (<http://www.nhq.nrcs.usda.gov/hu/ni170304.html>)
Each 7th code HU was coded with a 6th code HU number to identify which adjacent 7th code HUs to combine. To do this, the BLM and SNF contributed paper maps, concept lines, or 7th codes HUs coverage attributed with a 6th code HU number. On occasion a sixth code was small and further subdivision was inappropriate. So the 7th code polyon is the same as the 6th code polygon. A 6th code coverage can be created from the 7th code coverage by merging adjacent polygons with the same 6th code number using the Arc/Info command dissolve. Each polygon was attributed with 4th and 5th code HU name, complete 5th code HU number, 6th code number, 7th code number and watershed type-true/composite/frontal for both the 6th and 7th code HUs.