PORT ANGELES — For nearly 100 years, the Elwha Dam has proven to be a worthy adversary for spawning salmon.
Its impenetrable 108-foot wall has left 80 miles of mostly pristine habitat in the Elwha River out of reach since it was constructed in 1913.
And as the three-year process to remove the structure and its even larger cousin upstream, the 210-foot Glines Canyon Dam, nears, spawning salmon are coming across another large, though benign, man-made obstacle.
A 200-foot-long temporary fish weir — the largest on the west coast outside of Alaska, according to state Fish & Wildlife biologist Kent Mayer — stretches the entire width of the river a few miles upstream from the Strait of Juan de Fuca.
Made up mostly of PVC pipe, the floating structure corrals spawning salmon into traps where a small team of scientists are working briskly to take scale and DNA samples.
The purpose: to learn as much as possible about the stream’s depleted salmon populations before the river changes forever as the result of a $325 million federal restoration effort.
That way, scientists have comparison data as the ecosystem recovers.
Much like the spawning salmon, the scientists find themselves in a race against the clock. Dam removal begins Sept. 15.
“The truth is, this is all work that no one has” done before on the river, Mayer said as he prepared to pull a lively pink salmon from one of the traps.
But Mayer and the two other scientists manning the weir — Northwest Fisheries Science Center biologist George Pess and state Fish &Wildlife researcher Andrew Simmons — are not alone.
A slew of researchers from state, federal and tribal agencies have been studying the river’s watershed over the past decade in the hopes of learning as much as they can from this large living laboratory.
The dam removal project is considered to be the largest in the nation’s history, if not the world, and the prospect of reopening an unprecedented amount of untouched habitat to spawning fish has given researchers like Jeff Duda of the U.S. Geological Survey plenty to be excited about.
“It’s a once-in-a-lifetime project,” said Duda, a research ecologist.
“One thing about the Elwha that is so unique is you are opening up pristine habitat protected as wild in Olympic National Park,” he added.
“I don’t think there’s an equal anywhere in the world.”
And their efforts go beyond the study of salmon.
From the mouth of the Elwha to the Olympic Mountains, scientists have been mapping, sampling — and, yes, even snorkeling — the watershed to understand how the dams have affected the entire ecosystem.
One of the biggest issues is sediment.
Between 21 million and 28 million cubic yards of it sits behind the two dams, starving the last five miles of the river of much-needed silt.
That’s enough to cover football fields stacked 11 times the height of the Empire State Building, Duda said.
Of that, between 25 percent and 33 percent is expected to wash downstream, he said.
The effects of this loss of sediment are fairly clear. Fish lose spawning habitat, and Port Angeles’ Ediz Hook and beaches near the river’s mouth face increased erosion.
But how the release of the sediment over time will impact the ecosystem remains a bit murky, scientists said.
“We’ll just have to see,” said Jon Warrick, a USGS research geologist.
“One of the exciting things about doing this is it’s never been done before. We are going to learn a lot along the way.”
One of the concerns is that the sediment will actually destroy large portions of the already-threatened salmon runs.
Pess said he is hopeful that the river’s side channels will provide the fish with a safe refuge.
“These systems are very resilient,” he said.
Still, the tribe and state are taking precautions by stepping up their hatchery programs for the river.
But some hatchery fish will be planted to hasten repopulation.
Salmon populations are expected to increase to pre-dam levels of 400,000 spawning annually by 2039. The current estimated population is 3,000.
Not all of the river’s fish that are being protected are native to the ecosystem.
The Chambers Creek steelhead, raised by the tribe and by the state before that, will still be hatched after dam removal.
The purpose is to maintain the steelhead fishery since the native run is endangered, said Robert Elofson, tribal Elwha River restoration program director.
The use of the steelhead from the Tacoma creek, and hatchery fish in general, to repopulate the river has prompted criticism from the scientific community.
“If we leave these things alone, they will do a better job of repairing and fixing the systems than if we engineer a repair,” said James Karr, a University of Washington fisheries professor who will speak at the upcoming Elwha River science symposium.
Karr said he is concerned that the Chambers Creek steelhead will introduce genetic variations to the ecosystem and compete too much with the native populations.
“I think the real trick will be whether . . . the deficiencies in that plan will be accepted and accounted for as the project continues,” he said.
Elofson said there has been no evidence of interbreeding between the native and Chambers Creek steelhead and noted that their spawning periods are for the most part separate.
No matter how successful the restoration effort turns out to be, Duda said, he and other scientists are looking forward to telling the story of the Elwha.
“That’s really our challenge and our goal,” he said.
But they hope for the best.
“When I kind of fantasize about the next couple years, one of the highlights for me is being up in the upper Elwha somewhere and snorkeling and seeing the first pioneers of recovering salmon back in those areas,” Duda said.
“That to me would be a personal highlight in my life.
“I think I’m going to see that, and I look forward to the day that it happens.”
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Reporter Tom Callis can be reached at 360-417-3532 or at tom.callis@peninsuladailynews.com.
