Lake Marie Flows to Provide Improved Fish Habitat


A settlement agreement ending litigation between the California Department of State Hospitals and Water Audit California that was announced today will improve conditions for fish in Camille Creek while allowing Skyline Park visitors to continue to enjoy Lake Marie as a hiking destination. This resolution is representative of two principles: we can manage what we measure, and we can always do better.

Clear, cold water from the headwaters of Camille Creek flows into Lake Marie year-round. Below the Lake Marie dam, the creek passes through Skyline Park and residential neighborhoods. The mouth of the creek is at the Napa River near the Napa County Animal Shelter.

Lake Marie was built around 1880 and upgraded in 1908. The fourth jurisdictional dam built in the state, it is one of the oldest in California. Its history reflects Napa’s development from the earliest days of ranching. Lake Marie supplied water for Napa State Hospital for most of a century and supported hundreds of acres of farming and ranching activities until after World War II. Water is now supplied to the hospital from other sources, and in place of agriculture is the Skyline Park. With 1,020-acres of wildland crisscrossed by trails, the park is the nearest destination for hiking and mountain biking for many Napa residents.

California Fish and Game Code section 5937, adopted in 1915, requires dam owners to bypass enough flow to allow fishes living downstream to thrive. Like most dam owners, the Department of State Hospitals never operated their dam in accordance with the rule, and, for more than a century, no water has been bypassed for fish. This creates artificially dry conditions downstream and makes it harder for fishes to survive. An alternative to bypassing flows would have been removing the dam to allow water to flow freely, but as Lake Marie is a destination with abundant recreational benefits, removing the dam was not seen as a preferable option by either party.

A habitat assessment by R2 Consultants estimates that providing even small early summer flows will provide substantial benefits to Napa fishes. It was learned that young out-migrating anadromous fish, spawned upstream in the Napa River, use the waters below Lake Marie as their last opportunity to feed and mature before going to the ocean. More and cooler water to swim in and increased food availability in the early summer months will support additional fish growth, and therefore higher survival and return rates.

At this time, between 60 and 120 steelhead reared in Camille Creek are estimated to return from the sea to spawn annually. The projected ten-times survival rates means that Camille Creek could produce 600 to 1,200 adult steelhead in average and good water years.

This settlement is the next step in Water Audit’s Napa Valley remediation program that has so far included securing dam bypasses from Kimball, Rector, Bell Canyon dams, and the removal of obstructions to spawning in Garnet and York Creeks.

Water Audit California is a California public-benefit corporation
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