Datasets

Access Details:

The epa.gov access link goes to Access National Hydrography Products where the WBD NHDPlus V2 WBD snapshot (a component of NHDPlus V2) can be accessed under the heading National Hydrography Dataset (NHD).

Description:

NHDPlus V2 WBD Snapshot
Several snapshots of the WBD were used in the production of the NHDPlus V2 data as the process took multiple years to complete. For the conterminous United States, nine different WBD snapshots were used, dated from August 2010-February 2012. Between 2012 and 2016, NHDPlus data was developed for the state of Hawaii and U.S. territories including Puerto Rico, the Virgin Islands, Guam, Saipan, and America Samoa, using WBD snapshots dated from February 2012- February 2016. NHDPlus V2 data is not available for Alaska.
Two key components of the WBD were used in the development of NHDPlus V2. The 4-digit hydrologic units were used as the vector processing units, or outer extent, for production of the data while the 12-digit hydrologic units were used in the pre-processing of the raster datasets as built-in walls forcing the flow across the landscape to be contained within the hydrologic units where appropriate.
What is the Watershed Boundary Dataset (WBD)
The Watershed Boundary Dataset (WBD) is a seamless, national, hydrologic unit dataset that provides a standardized base for water-resources organizations to locate, store, retrieve, and exchange hydrologic data; to index and inventory hydrologic data and information; to catalog water-data acquisition activities; and to use in a variety of other applications. Hydrologic unit boundaries in the WBD are determined based on topographic, hydrologic, and other relevant landscape characteristics without regard for administrative, political, or jurisdictional boundaries.
The hydrologic units (HU) in the WBD are arranged in a nested, hierarchical system with each HU in the system identified using a unique hydrologic unit code (HUC). Each HU within a nested level is assigned a two-digit suffix that’s appended to the HUC of the HU in the next coarsest nesting level. Because there are eight nesting levels within WBD, the set of HUCs consists of ranges from two to sixteen digits based on the eight levels of classification in the WBD. The dataset is complete for the United States to the 12-digit hydrologic unit. The 14- and 16-digit hydrologic units have only been published for a subset of the nation. https://www.usgs.gov/media/images/watershed-boundary-dataset-structure-visualization

Additional Information: