Watershed Boundary Dataset; 12-Digit Watersheds Dissolved to 8-Digit Watersheds

This dataset is the digital hydrologic unit boundary layer for the 8-digit subwatershed boundaries
for the conterminous United States. This dataset is intended to be used with the following two
tabular dBase files: https://water.usgs.gov/lookup/getspatial?ds573_tillage_lu92e and
https://water.usgs.gov/lookup/getspatial?ds573_tillage_lu01. The two tabular datasets contain
the Tillage Practices in the Conterminous United States, 1989-2004---Datasets Aggregated by
Watershed. This dataset and the two tabular datasets can be linked using the common attribute
HUC8_N. Information about how the tabular data and geospatial data can be related are given
in the data series report: https://pubs.usgs.gov/ds/ds573/ .The original dataset is the 12-digit
Subwatershed boundaries (WBD_archive_17nov2009_9.2_file). The 12-digit boundaries were
dissolved to 8-digit boundaries to be used with the two tabular .dbase data files containing the
tillage practice data for the United States.

ORIGINAL METADATA:
This data set is a complete digital hydrologic unit boundary layer to the Subwatershed (12-digit)
6th level for the entire United States. This data set consists of geo-referenced digital data and
associated attributes created in accordance with the "Federal Guidelines, Requirements, and
Procedures for the National Watershed Boundary Dataset; Chapter 3 of Section A, Federal
Standards, Book 11, Collection and Delineation of Spatial Data; Techniques and Methods
11-A3" (04/01/2009). http://www.ncgc.nrcs.usda.gov/products/datasets/watershed/index.html .
Polygons are attributed with hydrologic unit codes for 4th level sub-basins, 5th level watersheds,
6th level subwatersheds, name, size, downstream hydrologic unit, type of watershed,
non-contributing areas and flow modification.