TACOMA - A $12 million restoration effort in the Nisqually National Wildlife Refuge begins Monday as crews work to re-establish more than 21 miles of sloughs and channels in the delta between Tacoma and Olympia.

The U.S. Fish & Wildlife Service and Puget Sound watershed groups have pooled salmon recovery and restoration money for the project, which includes replacements for some dikes and restoration of tidal flow across more than 750 acres of former farmland. Nearly $4.5 million is needed to complete the project.

Washington State Department of Ecology

Nisqually Delta

The effort is intended to more than double the salt marshland and to double the survival of naturally spawned Chinook salmon.

Absence of a natural estuary has hampered salmon survival, said Curtis Tanner, a federal biologist who helped draft the restoration plan.

The restored estuary should provide a haven for young Chinook, and tribal consultants say it eventually could support returns of as many as 15,000 naturally spawned salmon.

Native Nisqually River Chinook have been extinct for more than 30 years, but over time the fish originating from other river systems are expected to adapt and produce self-sustaining runs.

"I can't underestimate its significance in terms of our ability to recover salmon, but it's not just a salmon project. It has huge ecosystem benefits throughout southern Puget Sound," said Jeanette Dorner, the Nisqually Tribe's salmon recovery program manager.

This year crews plan to build a new dike and a 246-acre freshwater wetland at the refuge, which was established in 1974.

Next year, they expect to remove an existing dike, leaving a new 9,700-foot barrier to hold back the tides, and to complete a 3-mile trail and boardwalk that would provide seasonal access for visitors to tidelands near McAllister Park.

The project has been in the works for nearly 10 years and comes two years after an effort by the Nisqually Tribe, which gave 140 acres of cattle ranchland back to the waters.

Together, the two projects total more than 900 acres of marsh.