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California Hydrologic Units

State of California
  • Added 05 Sep 2018

Abstract: This data set is a complete digital hydrologic unit boundary layer to the Subwatershed (12-digit) 6th level for California. 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"( 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.

Purpose: 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 250,000 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 consistent geospatial database as other states complete their portion of the watershed boundary dataset.

Use_Constraints: The distributor shall not be held liable for improper or incorrect use of this data, based on the description of appropriate/inappropriate uses described in this metadata document. It is strongly recommended that this data is directly acquired from the distributor and not indirectly through other sources which may have changed the data in some way. These data should not be used at scales greater than 1:24,000 for the purpose of identifying hydrographic watershed boundary feature locations in the U.S.A. The NRCS should be acknowledged as the data source in products derived from these data. The Watershed Boundary Dataset is public information and may be interpreted by all organizations, agencies, units of government, or others based on needs; however, they are responsible for the appropriate application of the data. Federal, State, or local regulatory bodies are not to reassign to the Natural Resources Conservation Service any authority for the decisions they make. The Natural Resources Conservation Service will not perform any evaluations of these maps or purposes related solely to State or local regulatory programs. Photographic or digital enlargement of these maps to scales greater than that at which they were originally delineated can result in misrepresentation of the data. If enlarged, the maps will not include the fine detail that would be appropriate for mapping at the small scale. Digital data files are periodically updated. Files are dated, and users are responsible for obtaining the latest version of the data from the source distributor.

© Natural Resources Conservation Service (NRCS) USDA


Copyright Copyright may apply. Please check the source for more information.

Technical Details

Layer ID 96058
Data type Vector multipolygon
Feature count 4499
Attributes HUC12, States, NonContributingSqKm, Name, AreaSqKm, TNMID, GNIS_ID, SourceOriginator, SourceDataDesc, NonContributingAcres, LoadDate, HUType, HUMod, Shape_Length, SourceFeatureID, ToHUC, MetaSourceID, AreaAcres
Services Vector Query API

Added 5 Sep 2018 ago
Last checked 4 Mar 2021 ago
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