California Hydrologic Regions GIS Map
Hydrologic regions are a part of a larger hierarchical system of classification adopted by the United States Geological Survey. In this method, hydrologic regions are geographic areas that contain the drainage area of a major river or series of rivers. This information is traditionally mapped upon various types of boundaries including at a national, state, and county level. However, to an individual trying to understand this data with relation to their immediate community, it is often hard to contextualize such large geographic areas. Therefore, we have attempted to map the hydrologic regions of California by ZCTA* boundaries.
*ZIP Code Tabulation Areas (ZCTAs) are geographic regions produced by the U.S. Census Bureau that reflect the most frequently-occurring ZIP code in a region determined by Census blocks. In comparison, ZIP codes, which are often mistaken to be geographical entitities, are simply identifications for the U.S. Postal Service and are not restricted to any traditional boundaries such as state, county, census tract, census block, etc.
Using this Map Data
This map is available for free for non-profit use, if cited properly.
Required minimum citation includes the source name, map name, year published, and links back to project page (or displays url). Example: "Source: UC Berkeley RAEL CoolClimate Division Hydrologic Regions Map (2012)"
File Download
Download Microsoft Excel Spreadsheet (.xls) Version
