Utom, also called the Santa Clara River, is the wild heart of Southern California. Its watershed — the largest in the area to remain in a fairly untamed state — is also one of the region’s best, last wild places. Flowing for about 116 miles from its headwaters in the Angeles National Forest to the Pacific Ocean between Oxnard and Ventura, it’s now Southern California’s only publicly accessible, free-flowing river. In a region that has lost 97% of its historic river woodlands, the river is a rare riparian oasis sustained by its many tributaries, including Santa Paula Creek, Sespe Creek, Piru Creek, Bouquet Canyon, Mint Canyon, San Francisquito Canyon and Placerita Canyon.

The Utom watershed is home to 15 sensitive habitats and a vast diversity of plants and animals, including more than 110 special-status species. In arid Southern California, water-dependent ecosystems host unique plants, plant communities and animals. Utom itself supports highly localized fish species like the unarmored threespine stickleback, which is mainly limited to slow-water areas of the Santa Clara tributaries and mid-mainstem, and the unique and important Southern California steelhead trout, whose historic run the Center is working to reestablish.

Critically endangered California red-legged frogs, arroyo toads and other amphibians need the river and its tributaries to breed, while rare migratory birds like southwestern willow flycatchers, least Bell’s vireos and secretive yellow-billed cuckoos nest in its riparian zones. And California condors soar on thermals above the watershed from the Sespe Condor Sanctuary, which provides a safe haven for their rebound from extinction.

Our Campaign

We’re working to protect Utom through litigation, policy advocacy and educational outreach. In 2021 we secured a victory against a destructive development that would have destroyed an entire tributary of Utom known as Grasshopper Creek.  A few months later, federal officials released an updated status review for the critically endangered unarmored threespine stickleback after we filed a lawsuit challenging their failure to protect the fish. In 2020 we and our allies at Wishtoyo Foundation won an appeals court ruling that a water district must implement a long-term steelhead passage solution for Vern Freeman Dam and release enough water downstream for steelhead to migrate.

Our goal is to keep Utom wild and ecologically functional — to preserve a priceless part of Southern California and the myriad plants and animals that call this watershed home.


Utom photo by J.P. Rose/Center for Biological Diversity.