Upper Santa Ana Valley – San Timoteo

Upper Santa Ana Valley – San Timoteo



Located in California’s hydrologic region, the Upper Santa Ana Valley – San Timoteo is 158,534.44 acres in size. This Very Low priority basin is home to an estimated 50,453 people (2010 value), which have been at a rate of 60.73.

Upper Santa Ana Valley – San Timoteo is a(n) basin with approximately 390 wells, of which approximately 38 are water supply wells. Groundwater accounts for approximately 98 percent of the basin’s water supply.

Basin Notes

2004: Bulletin 118 basin description

Incomplete basin boundary modification request pending with DWR

Santa Ana Watershed Project Authority

21.40% adjudicated 

2019: Basin boundary modification. Per DWR: It “removes areas of low permeability, well- consolidated bedrock from the basin. The revised basin boundary follows geologic contacts of alluvium and bedrock using a qualified geologic map.” Phase 2 draft priority: very low.


GSA Information

Author: Admin Think

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