Temecula Basin

Temecula Basin is a sedimentary basin, which along with the Aguanga Basin, is part of the Elsinore Fault Zone, in southwestern Riverside County, California. The Temecula Basin is a basin of down faulted Mesozoic basement rock, overlain by late Cenozoic continental sediments.

The Temecula Basin is also a local ground water basin and aquifer in southwestern Riverside County. It is the largest groundwater basin in the San Diego water region. This aquifer is recharged by precipitation in the valley, underflow and by surface flow from the creeks draining the surrounding mountains and the southern Perris Block in the watershed of Murrieta Creek and Temecula Creek, tributaries of the Santa Margarita River.

In 1919, a USGS Water Supply Paper described the Temecula Basin:

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