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Example of groundwater basin/subbasin
map and description available in IWRIS
Groundwater Basin Maps and Descriptions
Out of 431 delineated groundwater basins, 24 basins are subdivided to create an additional 108 subbasins. These 515 distinct groundwater systems underlie about 40 percent of the surface area of the State.
Many of the subbasin boundaries were developed or modified with public input, but little physical data. Because they should not be considered precise boundaries, a detailed local study should determine whether any specific area lies within a groundwater basin boundary.
Basin descriptions are based on the best available information. In basins where many studies have been completed and the basin has been operated for a number of years, the basin response is fairly understood and the boundaries are well defined. Even in these basins, however, there are many unknowns and the boundaries may change as more information is collected and evaluated.
To view groundwater basin and subbasin descriptions, go to DWR's Integrated Water Resources Information System (IWRIS) web site.
IWRIS is a GIS-based web application that allows the user to access, query, integrate, and visualize different sets of data.