Subbasin Boundaries, California (8-digit HUC), 2012

Description:

This polygon shapefile contains the 4th level, 8-digit hydrologic unit code (HUC) sub-basin boundaries for California. A hydrologic unit is a drainage area delineated to nest in a multi-level, hierarchical drainage system. Its boundaries are defined by hydrographic and topographic criteria that delineate an area of land upstream from a specific point on a river, stream or similar surface waters. A hydrologic unit can accept surface water directly from upstream drainage areas, and indirectly from associated surface areas such as remnant, non-contributing, and diversions to form a drainage area with single or multiple outlet points. Hydrologic units are only synonymous with classic watersheds when their boundaries include all the source area contributing surface water to a single defined outlet point. The National Cartography and Geospatial Center (NRCS) modified the National WBD dataset with the intention of creating a seamless dataset for the entire country by all 6 levels. The data is delivered by sub-basin and includes data for HUC-8, HUC-10, and HUC-12. The deliverable includes attributes for hydrologic unit codes, hydrologic unit name, downstream hydrologic unit, man-made modifications to overland flow that alter the location of the HU boundary, and HU type for each hydrologic unit level 1-6. An acres field already exists for each subwatershed.This layer consists of georeferenced digital data and associated attributes created in accordance with the "USGS National Map Accuracy Standards and the NRCS Federal Standards for Delineation of Hydrologic Unit Boundaries, 10/01/04." These data were developed by digitizing watershed and subwatershed boundary lines using 1:24,000-scale digital raster graphics (DRG), high-resolution digital watershed datasets, a high-resolution National Hydrography Dataset (NHD) at 1:24,000-scale, and 1:250,000-scale draft hydrologic boundary lines. A 30-meter National Elevation Dataset (NED) was used to produce the 1:250,000-scale preliminary draft boundaries, as well as a hillshade layer for additional reference. Some draft catchments (watersheds/subwatersheds) were also created with Watershed Boundary Dataset tools (ArcHydro Tools, Version 9), using the NED for terrain analysis and the NHD for determining stream flow direction. Polygons are attributed with the following: hydrologic unit codes for 6th level subwatersheds; HU sizes (in acres); states containing the HUs; non-contributing areas; and downsteam hydrologic units. The watershed and subwatershed hydrologic unit boundaries provide a uniquely identified and uniform method of subdividing large drainage areas. This dataset 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. Wyoming Geographic Information Sciences Center. (2013). Subbasin Boundaries, California (8-digit HUC), 2012. Wyoming Geographic Information Sciences Center. Available at: http://purl.stanford.edu/sr396hp9621. The definition for a hydrologic unit according to the FGDC Proposal, Version 1.0 - Federal Standards For Delineation of
Hydrologic Unit Boundaries 3/01/02 states “A hydrologic unit is a drainage area delineated to nest in a multi-level,
hierarchical drainage system. Its boundaries are defined by hydrographic and topographic criteria that delineate an
area of land upstream from a specific point on a river, stream or similar surface waters. A hydrologic unit can accept
surface water directly from upstream drainage areas, and indirectly from associated surface areas such as remnant,
non-contributing, and diversions to form a drainage area with single or multiple outlet points. Hydrologic units are
only synonymous with classic watersheds when their boundaries include all the source area contributing surface water to a
single defined outlet point. “ This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.

Resource Link:

https://purl.stanford.edu/sr396hp9621

Identifier:

https://purl.stanford.edu/sr396hp9621

Language:

English

Creator:

Wyoming Geographic Information Sciences Center

Publisher:

Wyoming Geographic Information Sciences Center

Provider:

Stanford

Resource Class:

Datasets

Subject:

Hydrology, Watersheds, Inland Waters, and Planning and Cadastral

Temporal Coverage:

2012

Date Issued:

2013

Spatial Coverage:

California

Access Rights:

Public

Format:

Shapefile