Wyoming Hydrologic Unit Boundaries to the 6th Level at 1:24,000-scale

The Watershed and Subwatershed hydrologic unit boundaries provide a
uniquely identified and uniform method of subdividing large drainage
areas. The smaller sized 6th level sub-watersheds (up to 250,000
acres) are useful for numerous application programs supported by a
variety of local, State, and Federal Agencies. This data set is
intended to be used as a tool for water-resource management and
planning activities, particularly for site-specific and localized
studies requiring a level of detail provided by large-scale map
information. The dataset will be appended to a larger seamless
nationally consistant geospatial database as other states complete
their portion of the watershed boundary dataset. 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.

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.sdvc.uwyo.edu/. 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.