An ambitious effort to save fish in the Russian River watershed took another step forward this week with ground-breaking of a habitat restoration project along Dry Creek.

The work just below Warm Springs Dam on the Russian Rivet tributary is intended to provide refuge for endangered Coho salmon and threatened Steelhead, native fish that require pockets of slow-moving water to survive.

"We hope to keep the species from extinction," said Michael Dillabough, U.S. Army Corps acting park manager at Lake Sonoma.

Army Corps Lt. Colonel John Baker described the $1.8 million project along 1,600 feet of Dry Creek as a milestone in the ongoing collaborative effort to restore the fish population.

He said it will be a pilot for the eventual habitat enhancement of six miles of Dry Creek, a project that is estimated to cost from $36 million to $48 million by the time it is completed in 2020.

"It should get us well on the way to recovering this species," said Dick Butler, a supervisor in the National Marine Fisheries Service.

The environmental work is intended to offset the loss of fish habitat created by the construction of Warm Springs Dam three decades ago. The dam helps with flood control and also provides the bulk of water for 600,000 Sonoma County Water Agency customers in Sonoma and parts of Marin counties.

A significant portion of the habitat restoration funding will come from an ongoing tax assessment levied on property owners in Sonoma County that paid for the dam.

Representatives from federal, state, county and Dry Creek Rancheria tribal officials gathered Wednesday to laud the environmental work.

The Army Corps portion involves building a secondary side channel for fish spawning and rearing to mitigate the wide range of flow releases from the dam.

More than 70 logs, 250 large boulders and 320 cubic yards of spawning gravel and cobble will be installed in the side channel to help create the desirable fish refuge.

A similar amount of spawning gravel will be strategically placed in the main Dry Creek channel.

Coho and steelhead thrive in cooler, slow moving water where they can spend a year or two before migrating to the ocean. The project helps create shade, as well as places for fish to hide from birds of prey.

"Dry Creek is ground zero for species recovery within the Russian River watershed," said county Supervisor Mike McGuire, who was also present at the ground-breaking ceremony.

He said the work will also involve bank stabilization and the removal of invasive species, replacing them with native plants.

The environmental restoration is within Dry Creek Pomo ancestral lands, and close to a cultural and ceremonial center the tribe is planning near the base of the dam.

It is also the site of the some of the sedge used in native basket-making. Officials are working in tandem with the tribe to preserve the unique vegetation.

"What's accomplished here today, you can't put a price tag on. The loss of a species is a tragedy," said Gus Pina, Dry Creek tribal administrator. "The fact this community has learned the value of a species of fish speaks volumes."

Biologists say there are thousands of threatened Chinook salmon and even tens of thousands of Steelhead in a good year in the Russian River watershed. But only about 380 adult Cohos returned last year.

The habitat enhancement resulted from a 2008 requirement by the National Marine Fisheries Service, which also mandated reduced flows in the Russian River in the summertime and enhancement of the Jenner estuary.

The in-stream improvements are seen as a way to help the fish without having to reduce the flow of Dry Creek, or as a last resort build an additional pipeline to Lake Sonoma that could cost $141 million.

Meanwhile, several miles downstream from the dam, the Sonoma County Water Agency is putting finishing touches on a similar restoration project it launched last month.

It includes a fish-friendly passage constructed under a West Dry Creek Road bridge, near Quivira Winery.

Instead of having to negotiate a cement slab with shallow water during low flows, fish will have a series of pools and weirs with deeper water, said David Manning, a Water Agency environmental specialist.

So far, the results have been encouraging. Last month after placing rocks and logs in a side stream area, biologists discovered a wild young Coho salmon taking refuge among a newly placed "root wad."

"It was very exciting," said Manning.

He said there are small numbers of Coho along the 14-mile length of Dry Creek.

"It gives us hope as we create habitat those numbers will increase," he said.