The Santa Clara River Watershed, named for the largest river in the system, drains an extensive and biologically rich region at the junction of 5 of California’s 10 identified bioregions, and contains a particularly strong representation of the biodiversity in the South and Central Coast bioregions. The river is the last major coastal system in southern California that retains much of its natural hydrology and still provides the ecosystem functions necessary to sustain more than 17 federally listed species. The river system provides critical habitat and landscape linkages between these bioregions, including the Sierra Madre and Santa Felicia Mountains to the north, and Santa Susana-Simi Hills and Santa Monica Mountains to the south. The river basin also supports some of the most valuable agricultural resources in the world, as well as water resources for surrounding urban populations. Although the Santa Clara River contains extensive natural areas, it was identified as a critically endangered river by American Rivers in 2005 because of urban development and other threats in the region. Invasion by giant reed (Arundo donax) is also one of the most pressing conservation issues in the Watershed.
The Santa Clara River is the largest river in the Watershed. The headwaters are located in the San Gabriel Mountains, and runs 84 miles to Ventura Harbor, where it drains to the Pacific Ocean. The Santa Clara River is the second largest river in the state of California.
Piru Creek, Castaic Creek, and Sespe Creek are the primary tributaries of the Santa Clara River.
Pyramid Lake, Lake Piru, Castaic Lake, and Bouquet Reservoir are the major waterbodies located in the Watershed.
The Santa Clara River Watershed is located in both Ventura and Los Angeles Counties. The northern border is defined by the Santa Ynez Mountains, Sespe Mountains, San Cayetano Mountains, and Tehachapi Mountains. The eastern border is flanked by the San Gabriel Mountains. The lower Santa Susana Mountains define the southern border. See a map of it here!
The area of the Watershed is approximately 1,600-square-miles.
The Santa Clara River Watershed drains to the Pacific Ocean near Ventura Harbor.
For an interactive map of the watershed, click here.