San Diego Hydrogeology

This data set is a complete digital hydrologic unit boundary layer to the Subwatershed (12-digit) 6th level for the coterminous United States. This data set consists of geo-referenced digital data and associated attributes created in accordance with the "FGDC Proposal, Version 1.0 - Federal Standards For Delineation of Hydrologic Unit Boundaries 3/01/02"(http://www.ftw.nrcs.usda.gov/huc_data.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. Arcs are attributed with the highest hydrologic unit code for each watershed, linesource and a metadata reference file.

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 40,000 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.

• Watershed basins in the study area (PDF)
• Download shapefile - WBDHU8.zip, WBDHU10.zip, WBDHU12.zip
• Metadata - 19139 XML
• WBD data download viewer (National Map website)

Note: Users are recommended to obtain the latest Watershed Boundary Dataset (WBD) from the National Hydrography website (https://www.usgs.gov/national-hydrography/watershed-boundary-dataset).

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