Central Valley aquifer

Science Center Objects

Central Valley is virtually one large, sediment-filled valley in California between the Coast Ranges and the Sierra Nevada. The aquifer system is divided into three subregions on the basis of surface-water basins.

WAUSP Central Valley Aquifer photo 18

A huge volume of sediments of deep marine, shallow marine, deltaic, and continental origin fill Central Valley. Most of the freshwater, however, is contained in the upper part of the sediments consisting of post-Eocene continental rocks and deposits, with thicknesses ranging from 1,000 to 3,000 feet. The continental sediments consist mostly of basin-fill or lake deposits of sand and gravel interbedded and mixed with clay and silt. Depending on location, deposits of fine-grained materials-mostly clay and silt-compose as much as 50 percent of the thickness of the valley-fill sediments. Although a number of stratigraphic units have been identified (Tuscan, Tehama, Tulare, and San Joaquin formations), their spatial character and extent is poorly known. For the Central Valley Hydrologic Model, continental deposits were divided into 10 vertical layers and characterized using sediment textures (percent coarse-grained sediments).

The data files listed below are supplemental to Groundwater Availability of the Central Valley aquifer, California (USGS Professional Paper 1766). The report includes a description of methods used to derive the data.


Click on the links below to download files for this aquifer. For information about the available file types, see Aquifer data: Explanation of spatial data formats.

Borehole Data:

Extent of Central Valley Aquifer:  Metadata (19KB XML)    Shapefile (271KB ZIP)

Hydrologic Model Layer Surfaces:  Metadata (31KB XML)    Shapefile (all layers) (2.8MB ZIP)    Text file (1MB ZIP)