Lake Cachuma: Our Largest Water Supply Source

The majority of the District water supply is from the Cachuma Project, which the United States Bureau of Reclamation constructed on the Santa Ynez River in the early 1950s.  Lake Cachuma provides about 85 percent of the water for the 250,000 residents and 12,000 acres of agriculture along the South Coast of Santa Barbara County.  Supplies from Cachuma are also released for downstream water rights and federal fish protection requirements.  The District is entitled to 36 percent, or 9,322 AFY, of the Lake yield, which provides for approximately two-thirds of District customer demand in normal years.  

Cachuma supplies are delivered to the Goleta Valley through the Tecolote Tunnel and the South Coast Conduit and treated at the District Corona Del Mar Water Treatment Plant.  Using Cachuma supplies to meet the majority of District demand keeps customer costs low as Cachuma is the most inexpensive source of water available to the District.

Cachuma Project Facilities

The Cachuma Project consists of Bradbury Dam, Tecolote Tunnel, South Coast Conduit, and various water conveyance facilities.

  • Bradbury Dam: Bradbury Dam is a earthfill structure, containing 6,695,00 cubic yards of material, and standing 279 feet high.  The dam impounds up to 205,000 acre feet of water along the Santa Ynez River, approximately 45 miles from the river outlet at the ocean.
  • Tecolote Tunnel: Water is diverted from Lake Cachuma to the South Coast through the Tecolote Tunnel, which was bored approximately 6.4 miles through the Santa Ynez Mountains to the head works of the South Coast Conduit at Glen Annie Reservoir.
  • South Coast Conduit Pipeline and Reservoirs: The South Coast Conduit extends for a distance of approximately 24 miles along the South Coast from Goleta to Carpinteria, and includes four regulating reservoirs. The South Coast Conduit delivers Cachuma Project raw water to the District at the Corona del Mar Treatment Plant.  The Conduit also delivers water to the other South Coast Cachuma Member Units: City of Santa Barbara, Montecito Water District, and Carpinteria Valley Water District.