There are three reservoirs on the river, the largest of which is Lake Cachuma, with a capacity of . Bradbury Dam, which forms the lake, was built by the U.S. Bureau of Reclamation. Water from Lake Cachuma is diverted into the Tecolote Tunnel, which passes south under the Santa Ynez Mountains. The tunnel supplies water to the city of Santa Barbara (which uses it for drinking water), the Goleta Water District, the Carpinteria Valley Water District, and the Montecito Water District. Water from Lake Cachuma is released into the Santa Ynez River below Bradbury Dam in order to satisfy downstream water rights.