LAKE MILLS, Clallam County — Ever so gently, Dick Goin let four big chinooks go into Lake Mills above Glines Canyon Dam, some of the first of their kind to swim in those waters in a century.

Goin, 80, an Olympic National Park volunteer, was one of a select few to help release 10 big kings in all above Glines Canyon last week, on the eve of the start of the largest dam-removal project ever in U.S. history. "They were genuine Elwhas," Goin said of the four fish he let go, sounding a bit awe-struck.

All 10 fish were fitted with radio tags before the release, so scientists can track them at receiving stations and by airplane as the fish swim in the upper watershed.

That will enable scientists to learn how the fish travel in and use waters where they have not been since construction started on Elwha Dam in 1910. Removal of both dams on the Elwha is now under way and is expected to take up to three years.

Goin's family moved to the lower river when he was just 6, and he would become one of the first to push for taking the dams out of the river before it became a popular cause. "Oh heavens, this is something I have been waiting for," Goin said after letting the big fish go. "I literally am having trouble believing it's actually happening."

Seven male and three female chinooks were released, ranging in length from 27 to 34 inches. All were between 3 and 4 years old, according to the Washington Department of Fish and Wildlife.

The first reconnaissance flights by the National Park Service to track these fish may be as soon as Tuesday, and biologists expect to glean a lot of data. "We'll have very detailed movements on individual fish," said Sam Brenkman, head fish biologist for the Olympic National Park and leader of the tracking project.

The project is a cooperative effort among the park, the Lower Elwha Klallam Tribe, the National Oceanic and Atmospheric Administration Fisheries Department and state Fish and Wildlife.

Recolonization is expected to be a two-way street once the dams are out. Adult salmon will move from the saltwater into the river to spawn in some 70 miles of habitat. And there will be a reawakening of anadromy — oceangoing migration — in landlocked rainbow trout, headed downriver once more to sea as steelhead, when they have access to the saltwater Strait of Juan de Fuca.

Brenkman also led a comprehensive snorkel survey and mapping effort of the Elwha in 2007 and 2008, deploying 20 divers from the headwaters of the Elwha all the way to its mouth.

Scientists worked in teams of four, with two biologists counting fish in the water, and two on land mapping habitat, including glides, pools, riffles and logjams. The information was recorded with GPS to create detailed maps as the researchers covered about four miles of terrain a day. It took six pack mules to carry the 1,800 pounds of gear needed for their work in the backcountry.

Brenkman said he hopes tracking data from the radio-tagged fish, along with the mapping effort, will help scientists get a picture of how the habitat and utilization of the river change as the dams come out.

The 10 fish released last week were big, powerful and lively, thrashing in black cases that looked like gym bags carried by the biologists, who rushed them at a run from the hatchery truck to the release site. Snapping their jaws, the fish swam away like a shot once freed. Some briefly showed themselves as they investigated the surface of Lake Mills, then were seen no more.

Goin said he feels a debt to the big fish that helped keep his family fed during the Depression. "And I've had endless pleasure in the decades of fishing for them," he said.

At his age, Goin said, he doesn't know how much of the river's recovery he'll see. "But I hope I can make it to see a big king salmon go by."

Salmon populations today in the Elwha River are estimated at 1 percent of their pre-dam numbers. Four fish species in the river — bull trout, steelhead, eulachon and chinook — are listed as threatened under the U.S. Endangered Species Act.

Raymond Moses, a member of the Nez Percé Tribe who works for the fisheries department of the Lower Elwha Klallam Tribe, said that as he released one of the big kings, he felt "a sigh of relief.

"Like they were meant to be up here. In a part of the watershed they have missed for 100 years."

Lynda V. Mapes: 206-464-2736 or lmapes@seattletimes.com