Uvas/Llagas Watersheds

The Uvas/Llagas Watershed originates from both the Santa Cruz Mountains and the Diablo Range and drains to Monterey Bay. This is a largely rural landscape supporting farming communities and cattle ranches, and growing crops like garlic, artichokes, red bell peppers, and mushrooms. It also includes significant open space and natural areas.

The Pajaro River marks the southern boundary of Santa Clara County, as it abuts San Benito County. Within the geographical boundaries of Santa Clara County, major tributaries include Uvas Creek, Llagas Creek, and Pacheco Creek. South county businesses, residents, and farmers are primarily reliant on groundwater for their water supply, and the District actively recharges the Llagas Groundwater Subbasin by percolating local and imported water through a series of streams, channels, and percolation ponds.

The Uvas Creek and Llagas Creek subwatersheds cover a 104-square-mile region of the larger Pajaro River Watershed.Uvas Reservoir on Uvas Creek and Chesbro Reservoir on Llagas Creek are operated by the District and are important components in the recharge of groundwater.

Downstream of the reservoirs, several miles of both Uvas and Llagas creeks are located on the unconfined portion of the Llagas Groundwater Subbasin, which is the “recharge zone” where the creeks generally lose water via percolation into the aquifer.

The District operates a water transfer pipeline, the Uvas/ Llagas Transfer Pipeline, to transport excess water from Uvas Reservoir east to Llagas Creek in order to supplement percolation in Llagas Creek and the downstream Church Avenue off-stream Recharge Ponds. The Pacheco Pass Water District owns and operates Pacheco Reservoir located on North Fork Pacheco Creek, in the Pacheco Creek Watershed.