Ben White, a U.S. Army Corps of Engineers fisheries biologist, on Tuesday releases nine-month-old Coho salmon fingerlings into Willow Creek, near Bridgehaven. The creek is a major tributary to the Russian River estuary near Jenner.

Published: Tuesday, October 18, 2011 at 7:00 p.m.

Wearing waders and what looked like small kegs strapped to their backs, a team of government biologists slogged through Willow Creek near Jenner Tuesday searching for good places to let their precious cargos go.

Dipping nets into the aerated containers, the biologists released juvenile Coho salmon into the creek a couple at a time, allowing the silvery fish to dart away beneath a canopy of Redwood trees.

Tuesday's release of 11,000 Coho into Willow Creek marked a new phase in what has been a major and time-consuming effort to restore the endangered fish to the waterway, which is the largest of the tributaries flowing into the Jenner estuary.

A decade of planning that has involved numerous government agencies and non-profit organizations has so far gone into the restoration effort, which also has included spending more than $1 million to upgrade a bridge that was considered a main barrier to salmon thriving in the creek.

Observing Tuesday's fish release, Michele Luna, executive director of Stewards of the Coast and Redwoods, reminisced about the first planning meeting 10 years ago.

“We got a bunch of people in a room and said, ‘What do we need to do in order to do some restoration work on Willow Creek?'” she said.

The answer, as it turned out, was a lot.

Willow Creek, which flows nearly nine miles from Coleman Valley to the Jenner estuary, was once prime habitat for salmon. But run-off from logging and agricultural activities, coupled with the discontinuation of dredging efforts that were aimed at preventing roadway flooding, had turned the once pristine waterway into a clogged and meandering mess.

The watershed is mostly within Sonoma Coast State Park. It also flows in an area of privately-held ranches and land owned by the Mendocino Redwood Company.

A network of culverts that had been accumulating sediment after state parks purchased the property in 1987 and discontinued dredging were identified as significant impediments to Coho salmon being able to travel up and down the creek.

The stewards group proposed replacing the culverts with a 43-foot bridge that is nearing completion and that will re-establish connectivity through 1,000 feet of wetlands. The work, totaling more than $1 million, is being paid for with a combination of government grants.

Several of the agencies involved in the project had representatives on hand Tuesday, including from the U.S. Army Corps of Engineers, the National Oceanic and Atmospheric Administration, the California Department of Fish and Game, state parks and the Sonoma County Water Agency.

Joe Pecharich with NOAA said the federal agency is making the Willow Creek restoration effort a high priority — contributing $400,000 through the agency's Open Rivers Initiative — because it potentially buys “seven miles of additional habitat for endangered Coho salmon.”

Fish and Game put in $352,000 and Trout Unlimited secured $100,000 from the county water agency.

“It's really an exciting multi-agency collaboration that has been sustained for a number of years,” said David Manning, the supervisory biologist for the water agency.

The fish released Tuesday were raised at the Warm Springs National Hatchery, which is leading an effort to restore salmon populations in waterways across Northern California, including the release of 170,000 fish into 22 Sonoma County streams this fall.

As many as 50 percent of the salmon fingerlings released into Willow Creek Tuesday are expected to survive, according to Ben White, a fisheries biologist for the Corps. He said all of the fish have tiny wire tags implanted in their snouts, and that a smaller number carry transponders for more advanced tracking.

White said if all goes well, the fish will venture downstream in the spring and spend the next two years maturing in the ocean, before returning to the creek to spawn.

Bill Bambrick, president of the Stewards' board of directors, said the water tests that he and other volunteers have been conducting at Willow Creek since 2003 have revealed ideal conditions for Coho, including an average water temperature between 50 and 55 degrees.

“If they could get up here, they'd love it,” Bambrick said.