Abstract: This file contains Hydrologic Unit (HU) polygon boundaries for the United States, Puerto Rico, and the U.S. Virgin Islands. The data is a seamless National...
The purpose of the Wyoming Headwaters Project is to refine existing USGS Hydrologic Unit Boundaries (HUBs) published in the mid 1970's on a national level (level 4 HUBs). 5th a
Water Framework Directive (WFD) legislation requires the definition of both surface and groundwaters as a coherent set of hydrological units which could be monitored and managed. Certain parcels of...
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 250,00
