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When Dams Fell, Salmon Returned by Eric Barker Lewiston Tribune, December 12, 2021

In western Washington's Elwha River, the removal of two dams led to a
resurgence of fish runs; could a similar scenario play out on the Snake River?

PORT ANGELES, Wash. -- Mel Elofson thought of his ancestors when he spotted a chinook salmon swimming past the old Glines Canyon Dam site on the Elwha River here.

"It was not even 20 feet away," he said. "A nice, big, fat silver female."

For decades, members of the Lower Elwha Klallam Tribe called for the removal of two dams blocking the river and preventing several species of salmon and steelhead from reaching spawning grounds and they worked to make that vision a reality.

In 2012, the Elwha Dam came down. Two years later, Glines Canyon Dam was gone and the intrepid chinook spotted by Elofson pushed upstream just a day and a half later.

"We were high-fiving. It was pretty awesome to see. It was something my grandmothers and grandfathers and aunts and uncles wanted to see. I got to be their eyes, I guess."

Members of the Nez Perce Tribe share a similar vision. They have led a decadeslong fight to breach the four lower Snake River dams and free the lower Snake River so its salmon, steelhead and lamprey can thrive.

The Snake and Elwha rivers and their dams are very different. The Elwha is a short coastal stream surrounded by a temperate rainforest. It begins in Olympic National Park and gains speed and size as it races 45 miles north to meet the Salish Sea at the Strait of San Juan de Fuca.

"So a lot of it was never altered," said George Pess, a scientist with the National Oceanic and Atmospheric Administration at Seattle. "There wasn't road construction and timber harvest and all of that other kind of stuff that you have a lot of times in all of our watersheds."

But the dams, built to power mills at nearby Port Angeles, lacked fish ladders and blocked salmon and steelhead from progressing more than a few miles upstream.

The Snake River is long. It starts in Grand Teton National Park in Wyoming, covers about 1,000 miles as it courses across the width and length of Idaho and traverses southeastern Washington before joining the Columbia River near the Tri-Cities. Much of the land it slithers through is arid, but its tributaries reach high into the forested mountains and snowy peaks of central Idaho and northeastern Oregon, where wild salmon and steelhead still spawn in cool-running streams.

The four Snake River dams in eastern Washington have fish ladders for upstream-bound adults and elaborate systems to pass juvenile fish downstream. Nonetheless, the dams are a hindrance to the fish, and wild runs of spring, summer and fall chinook; sockeye salmon; and steelhead have needed Endangered Species Act protection for the past 30 years.

The tribe, Oregon and several fishing and environmental groups, backed by strong science, say breaching the dams will unleash the productivity of higher-elevation Snake River tributaries -- including the Salmon River and its middle and south forks, as well as the Imnaha, Grande Ronde, Clearwater, Selway and Lochsa rivers -- to save the fish from extinction.

To prove it, they point downstream to yet another river, the undammed John Day in Oregon. It joins the Columbia River about 100 miles downstream from the mouth of the Snake River after flowing north out of the Strawberry, Elkhorn and Blue mountains.

The Snake and John Day are closer than they might appear. Some of their headwaters share the same mountains in northeastern Oregon. They are both long (though the Snake is much longer) and both support wild runs of chinook and steelhead.

But they differ in the number of dams fish must negotiate between the ocean and spawning grounds and in the quality of spawning and rearing habitat used by those fish.

John Day River salmon and steelhead must negotiate three dams -- Bonneville, The Dalles and John Day -- on the Columbia during their migrations to and from the ocean. Snake River fish must get past eight dams -- four on the Columbia and four on the Snake.

The John Day, despite flowing through a sparsely populated region, has been significantly altered.

"In general, it's been heavily impacted by humans in most of the area," said Ian Tattam, a biologist with the Oregon Department of Fish and Wildlife at La Grande. "There is widespread agriculture and timber and grazing, and the roads and the water diversions and associated paraphernalia that go along with those activities."

As a result, the fish habitat is largely in much poorer shape compared to the habitat found in pristine Snake River tributaries like the Middle Fork of the Salmon River, Imnaha and Selway rivers. Yet its salmon and steelhead are doing considerably better than those in the Snake River basin.

Today the Tribune looks at the Elwha River and what has happened there since the dams were removed. Key topics include how the river dealt with the sudden animation of sediment trapped behind the dams and how salmon and steelhead and the river itself are responding.

Next week we will visit the John Day River, take a look at its habitat, and how its fish have fared.

Elwha

It's been less than a decade since the Elwha and Glines Canyon dams came down. As hinted at by that first chinook spotted by Elofson, a member of the Lower Elwha Tribe and an employee of its fisheries department, dam removal has allowed salmon to occupy habitat that was inaccessible for more than a century.

Fish numbers, while subject to normal ups and downs shaped by ocean and weather conditions, have generally responded positively to the regained access.

"We went from the first couple of years and having 100,000, 125,000, 130,000 (spring chinook) smolts go out ... to having 550,000 in one year. And we went from that to 1 million the next year," said Robert Elofson, Mel's brother and a fisheries department employee who served as a liaison with the National Park Service during the dam-removal process and lobbied Congress while legislation authorizing the project was up for consideration.

Coho and winter steelhead are holding their own and summer steelhead stormed back, surprising everyone. Pink and chum salmon have yet to make significant gains but fisheries managers are hopeful for a turnaround.

John McMillan, a fisheries scientist with Trout Unlimited's Wild Steelhead Project, marvels at the way summer steelhead recolonized the river. The run went from just a few fish, to nearly 1,000. McMillan said it is likely the largest summer steelhead run on the coast of Washington.

"What has been really exciting has not only been the increase in abundance we have seen in a lot of species, but we are starting to see new life histories arise that we didn't see before the dams were out," he said. "For example, summer steelhead have come back really strong, the bull trout have resumed migration back to the ocean and the king salmon are starting to produce remarkable numbers of naturally produced offspring."

Muck and moonscapes

Despite the success so far, there were significant uncertainties. About 26 million cubic yards of mostly sand and silt were trapped behind the dams, three-quarters of which was above Glines Canyon. That changed the way the river and its floodplain interacted during the life of the dams and posed a problem for dam removal -- where would it all go once the river was free?

"Sediment was the big question mark," Pess said.

It's a question many people have about the Snake River and the estimated 178 million cubic yards of sediment stored behind its dams.

Would the Elwha be so clogged with silt, sand and gravel that it would kill nearly everything? Would the emerald green and aqua blue pools fill with muck? Or would the sediment feed the floodplain during highwater pulses and allow the river to meander across the valley, splitting into side channels and create better habitat for fish? Would the sediment build up and create high banks? Or would it flush through the system and create a delta at the river's mouth?

"The answer to all of this is yes," Pess said. "It wasn't any one thing. All of these things happened to some extent."

The flow of sediment increased when the lower dam was removed. But the big pulses came after the removal of Glines Canyon and the movement of both fine sediments and larger bedload material. The effect on aquatic life, particularly the bugs that live between and under the rocks that make up the riverbed, was dramatic.

"That is where most of the productivity is happening in a stream system," said Sarah Morley, another NOAA scientist, who studies these creatures.

In 2012, when the sediment started to accumulate in the lower river, Morley and her team recorded a 95 percent drop in aquatic insects.

"I didn't expect it to be that extreme," she said.

"In the lower river we saw virtually all invertebrates wiped out. But by 2015, once the sediment was mainly through the river, there was a very rapid rebound."

Two years later, in 2017, everything, including numbers of invertebrates and the species composition, was back to normal.

During high-sediment periods, Morley said some fish seemed able to find alternative food, perhaps by feeding more on terrestrial insects that fell into the river.

"Even though there was so much less aquatic invertebrates available, they were still getting the same amount of energy in their diets."

Within four or five years, the sediment levels returned to normal.

"So even though we had a lot of sediment in a short period of time, the river was able to integrate that sediment and do what a river does with sediment, and that is move it or store it or do whatever it needs to," Pess said.

Some of it was deposited on the floodplain or stored in islands between braided channels and in sandbars. But the vast majority flushed through the system.

"Most of it just ended up in the Strait of Juan de Fuca," Pess said.

And in that body of water, it created a delta and estuarine habitat for juvenile fish.

"If you and I were standing (at the mouth) in 2006 and we closed our eyes, we would hear the surf and the surf would be like BAM, BAM because it would be big boulders and cobbles," Pess said. "If we were standing there in 2015 or even today, you would hear this swishing sound because it's all finer sediment.

"Before fish were coming out straight into the Strait of Juan de Fuca, the near shore was pretty minimal in terms of kelp forests or eel grass, but now we have a sandy beach with blind tidal channels."

The Army Corps of Engineers predicts the lower Snake River would go through a similar process of significant negative short-term effects from sediment movement, followed by long-term benefits for fish.

Nature's Band-Aids

McMillan, the Trout Unlimited scientist, snakes his way through a maze of willows and young cottonwood trees that reach high above his head. The 10-year-old vegetation is thick and tall -- maybe 15 to 20 feet. But a decade early, McMillan would have been underwater at the same spot.

"This was all lake bed, which is pretty amazing to think, and now it's all overgrown," he said.

The area that sat behind the old Elwha Dam is lined with river rocks and gravel. The river, braided into multiple channels, rushes past. It's a spot favored by chinook for spawning.

Further downstream, Mel Elofson stands on a bedrock cliff that was the anchor to the old Elwha Dam. In a downstream pool, a keen eye can see the dark shadows of adult chinook lurking as they stage before moving upstream.

He remembers what it looked like when the dam came down.

"It was like a moonscape once they drained all the water out. Not a single plant there. Now it's totally revegetated."

The scene is similar at the former site of Glines Canyon Dam and Lake Mills. What was once a reservoir is now a flowing river, with multiple channels. Alder trees, which Elofson calls nature's Band-Aids, have repopulated the former lake bed.

Snake River

Although proposals to breach the four lower Snake River dams hinge almost entirely on reducing the direct and indirect mortality juvenile fish suffer during their downstream migration, McMillan sees an important secondary benefit. He believes breaching will restore the lower Snake River floodplain and create critical resting and rearing habitat for the fish.

Just like the scenario that played out on the Elwha, McMillan thinks a free-flowing lower Snake River will emerge with increased complexity. What is now a flat, canal-like body of water would evolve into a river with islands, side channels, riffles, pools and rapids. He said gravel bars connected to groundwater will create cold-water oases.

"What this should do is provide basically a pit stop, like a resting stop for these fish to park and have some food, experience a little bit cooler water if that is what they need, and then resume their migration downstream."

Mel Elofson is a believer in the power of rivers and their salmon and steelhead to rebound if given the chance.

"It proves it works. It proves salmon can return and be resilient. They were totally resilient, just surviving that long, that many decades without being able to use their habitat."

His brother Robert also believes in the commitment of Native Americans and their allies to affect long-term change.

"We weren't going anywhere. We aren't going anywhere, and neither are the Nez Perce for that matter."