Basin Boundary Area
The Santa Cruz Mid-County Basin (Basin) covers approximately 57 square miles and extends from the Santa Cruz Mountains (east of Highway 17) from the Zayante fault (below Summit Road) to the Monterey Bay from Twin Lakes on the west to La Selva Beach on the east. The Basin includes a portion of the City of Santa Cruz, the City of Capitola, Santa Cruz County census designated places of Twin Lakes, Live Oak, Pleasure Point, Soquel, Seacliff, Aptos, and Rio Del Mar. The Basin also includes portions of Santa Cruz County unincorporated census designated places of Day Valley, Corralitos, Aptos Hills-Larkin Valley, and La Selva Beach.
Basin Map
Geology and Aquifers
The Basin includes three primary groundwater aquifers from shallowest in the east to deepest in the west: the Tu Unit, the Purisima Formation and the Aromas Red Sands. Underlying these aquifers is a solid quartz diorite that represents the bottom of the basin.