This data set is a complete digital hydrologic unit boundary layer to the Subwatershed (12-digit) 6th level for the State of Wyoming.This data set consists of geo-referenced digital data and associated attributes created in accordance with the "Federal Standards For Delineation of Hydrologic Unit Boundaries 12/06/01" (http://www.ftw.nrcs.usda.gov/huc_data.html). The data set was developed by digitizing watershed boundary lines using 1:24,000 Enhanced Digital Raster Graphics (DRG-E) geo-referenced topographic image base maps and 1:100,000-scale draft boundary lines. The National Elevation Dataset (NED) was used to produce the 1:100,000-scale preliminary draft boundaries. Polygons are attributed with hydrologic unit codes for 4th level sub-basins, 5th level watersheds, 6th level subwatersheds, name, size, downsteam hydrologic unit, type of watershed, non-contributing areas and flow modification. Arcs are attributed with the highest hydrologic unit code for each watershed, linesource and a metadata reference file. Two separate shapefiles were created for downloading purposes. One with arcs (wy_hu12arc.shp) and one with polygons (wy_hu12poly.shp). The same metadata is used for both shapefiles. Only the arc attributes will be found in the wy_hu12arc shapefile. Similarly, only the poly attributes will be found in the wy_hu12poly shapefile.
