California Instream Flow Resources

Along much of California’s coast, lack of streamflow – often caused by the diversion of water for human use – is a major impediment to recovery of salmon and steelhead. Trout Unlimited works with a diverse collection of partners on projects that improve dry season streamflow for the benefit of native coho and steelhead. 

Our work is based on a simple principle: the same projects help both fish and people.

Case studies:

Pescadero Creek is one of the last, best wild steelhead strongholds on California’s Central Coast and is likely the best chance for recovering coho south of San Francisco. TU and conservation partners have worked for years to improve streamflows and habitat conditions in this watershed. TU’s work has focused on collaborative projects with willing agricultural landowners in the lower watershed that will improve water security for farming and boost streamflows in the dry season when steelhead need it most. The BJ Burns/Bianchi Flowers farm project illustrated here is a fine example of how this kind of partnership can benefit both fish and people.

Little Arthur Creek provides the best remaining habitat for steelhead in the upper Pajaro River watershed. Trout Unlimited, CHEER, and CEMAR are working with residents along Little Arthur Creek to stop diverting water during the dry season by relying on stored water instead.

In Grape Creek, the Russian River Coho Partnership and Martorana Family Winery worked together to enable the family to use a fan instead of a water diversion to protect its vineyard from frost, leaving more water instream for coho and steelhead. The Partnership formed in 2009 to develop a systematic approach to improving streamflow and water supply reliability in five Russian River tributaries: Dutch Bill Creek, Green Valley Creek, Mark West Creek, Mill Creek, and Grape Creek. The Partnership is generously funded by the National Fish and Wildlife Foundation with additional support from the Sonoma County Water Agency. For more information, go to

The Mattole River is one of the most renowned steelhead fisheries in California but suffers from low flows due to increasing residential and agricultural demands. TU, Sanctuary Forest, and CEMAR developed a cooperative project with Whitethorn Elementary School to reduce the school’s diversion of water from the river during the dry season, while providing a stable source of water for the school year-round. The school now leverages the project as a learning opportunity for its students, who put their own delightful “spin” on issues of water, fish and nature in this short film.

Project fact sheets for download: