Description: The Watershed Boundary Dataset (WBD) is a comprehensive aggregated collection of hydrologic unit data consistent with the national criteria for delineation and resolution. It defines the areal extent of surface water drainage to a point except in coastal or lake front areas where there could be multiple outlets as stated by the "Federal Standards and Procedures for the National Watershed Boundary Dataset (WBD)" “Standard” (http://pubs.usgs.gov/tm/11/a3/). Watershed boundaries are determined solely upon science-based hydrologic principles, not favoring any administrative boundaries or special projects, nor particular program or agency. This dataset represents the hydrologic unit boundaries to the 12-digit (6th level) for the entire United States. Some areas may also include additional subdivisions representing the 14- and 16-digit hydrologic unit (HU). At a minimum, the HUs are delineated at 1:24,000-scale in the conterminous United States, 1:25,000-scale in Hawaii, Pacific basin and the Caribbean, and 1:63,360-scale in Alaska, meeting the National Map Accuracy Standards (NMAS). Higher resolution boundaries are being developed where partners and data exist and will be incorporated back into the WBD. WBD data are delivered as a dataset of polygons and corresponding lines that define the boundary of the polygon. WBD polygon attributes include hydrologic unit codes (HUC), size (in the form of acres and square kilometers), name, downstream hydrologic unit code, type of watershed, non-contributing areas, and flow modifications. The HUC describes where the unit is in the country and the level of the unit. WBD line attributes contain the highest level of hydrologic unit for each boundary, line source information and flow modifications.
Service Item Id: f57460da15de4834b9a67212f00fa366
Copyright Text: Funding for the Watershed Boundary Dataset (WBD) was provided by the USDA-NRCS, USGS and EPA along with other federal, state and local agenciesies. Representatives from many agencies contributed a substantial amount of time and salary towards quality review and updating of the dataset in order to meet the WBD Standards. Acknowledgment of the originating agencies would be appreciated in products derived from these data. See dataset specific metadata for further information
Description: This layer represents streams, rivers, and similar linear features that have been defined by the ADEC via qualitative and quantitative data. These features are noted in the 2014/2016 Integrated Report and currently being actively monitored or have institutional controls (TMDLs) in place, and are classified as Category 4a, 4b, or Category 5 under Section 303(d) of the Clean Water Act (1987). These 2014/2016 Impaired Waters should be used for regulatory purposes.
Copyright Text: Alaska Department of Environmental Conservation – Standards, Assessment, and Restoration
Description: This layer represents lakes, harbors and similar polygon features that have been defined by the ADEC via qualitative and quantitative data. These features are noted in the 2014/2016 Integrated Report and currently being actively monitored or have institutional controls (TMDLs) in place, and are classified as Category 4a, 4b, or Category 5 under Section 303(d) of the Clean Water Act (1987). These 2014/2016 Impaired Waters should be used for regulatory purposes.
Copyright Text: Alaska Department of Environmental Conservation – Standards, Assessment, and Restoration