RICHLAND – Ninety years ago, it took a juvenile Chinook salmon less than five days to swim the winding, 325-mile stretch of rivers from the Idaho Panhandle to the Pacific Ocean. Today it can take as long as one month, scientists say.

Chinook and steelhead populations must now traverse hundreds of barriers as they navigate the waterways of the Columbia Basin, including four dams on the Lower Snake River east of its confluence with the Columbia River in southwest Washington.

Those four Lower Snake River dams have been at the hull of a decadeslong push by local Indigenous and environmental leaders, calling for the federal government to breach the dams and restore the rivers’ habitats. Some local scientists now hope the controversial Snake River dams will be breached and see a fate similar to that of the Klamath River.

But others say there are better ways to help salmon without tearing out the dams, which they stress provide clean electricity and important economic benefits to farmers and others in the region. They also point to numbers of returning salmon and say breaching is unnecessary.

On Monday, U.S. House Republicans – Cliff Bentz of Oregon , Mike Collins of Georgia , Dan Newhouse of Central Washington and Cathy McMorris Rodgers of Spokane – stood in a gravel lot beside the Snake River, miles before its confluence with the Columbia. A sign with the words “NORTHWEST AT RISK” hung on the front of a wooden podium as the four politicians spoke at a press conference to defend the Lower Snake dams. The 2,822-foot-long Ice Harbor Dam towered over the quartet as they argued salmon and dams can “coexist.”

Newhouse referred to claims that dams hurt salmon populations as “baseless.”

“The truth is that the returns of the salmon have been improving – they’ve been increasing with these dams in place,” Newhouse said.

McMorris Rodgers said dam-breaching advocates “are not being honest,” arguing technology such as fish ladders and slides have led to “improving” salmon runs.

“This is the inconvenient truth of the dam-breaching crowd,” McMorris Rodgers said. “So that’s why it’s important that we are here today to show the rest of the world what is possible when we unleash the potential of these dams. To use the facts, not rhetoric. To lead with science. To hear from the experts.”

Yet Indigenous leaders and many scientists for nearly a century have studied dwindling fish populations in the rivers and say dams are to blame. For more than 16,000 years, Chinook salmon have played a vital spiritual, cultural and economic role for the Nez Perce Tribe, whose ancestral lands spanned parts of Washington, Idaho, Oregon and Montana.

Jay Hesse, director of biological services at the Nez Perce Tribes’ Department of Fisheries, said in a phone interview that the scientific community has identified hydropower systems in the Columbia Basin as the single-largest source of mortality and reduction of productivity of fish populations.

“Very clearly, the numbers of natural-origin fish and hatchery returns are dismally below our expectations,” Hesse said. “So much to the point that we don’t measure how close we are to being successful – we’re actually looking at how low those numbers are until they go away: extinction.”

Even though some dams have fish ladders and passages, the way their construction broke up river flow has altered ecosystems. Diminished currents mean fish must work harder to travel down the river, exposing them to elements and predators for longer and depleting their energy by the time they reach the Pacific.

Dams aren’t the only challenge salmon and steelhead populations face. A warming climate and increasingly polluted ocean habitats are harmful. But removal of the Lower Snake dams is crucial for habitat restoration, Hesse said.

“Compared to 2021, there were twice as many natural-origin spring-summer Chinook that came back in 2022,” Hesse said. “That sounds great. But when you go from 8,000 to 16,000 and your goal is 235,000, that’s just annual variation.”

Hesse said opponents of dam breaching often bring up small sets of data to make a point when fish populations have been steadily declining for decades.

After the four politicians spoke in front of the dam, they traveled about 30 miles west, across the Snake River, to Richland High School. There, they held a “field hearing” titled, “The Northwest at Risk: The Environmentalist’s Effort to Destroy Navigation, Transportation, and Access to Reliable Power.”

The members of Congress were joined onstage by nine panelists, including David Welch of Kintama Research Services in Nanaimo, British Columbia; Jennifer Quan of the National Oceanic and Atmospheric Administration; and Scott Corbitt, general manager of the Port of Lewiston.

Quan said the National Oceanic and Atmospheric Administration has listed 13 stocks of salmon and steelhead in the Columbia River Basin under the Endangered Species Act.

In 2020, NOAA fisheries issued its latest Endangered Species Act opinion, Quan said. The report “assessed and concluded that the operations and maintenance of the Columbia River system’s 14 dams was not likely to jeopardize the continued existence of listed salmon and steelhead or result in the destruction or adverse modification of their critical habitat.”

Two years later in 2022, NOAA released  a report that listed actions that could boost salmon such as breaching the Lower Snake River dams, habitat restoration and protection, fish passage in blocked areas and other management efforts in the ocean. Quan noted the report did not assess the social and economic impacts of implementing any rebuilding measures, nor did it suggest funding sources required for implementation.

“NOAA Fisheries recognizes that the important services the Lower Snake River Dams provide would need to be replaced or otherwise offset before breaching could occur,” Quan said.

Monday’s hearing was held a year following a report commissioned by U.S. Sen. Patty Murray, D-Wash., and Gov. Jay Inslee found the Lower Snake’s energy, transportation and irrigation benefits could be replaced for  $10.3 billion to $27.2 billion.

Michelle Hennings, executive director of the Washington Association of Wheat Growers, said at the hearing that farmers across the country rely on the Columbia River system for transportation benefits. Disruption to the system could hurt farmers’ trade relationships with customers around the world, she said.

“More than 60% of all U.S. wheat exports move through the Columbia and Snake river systems,” Hennings said. “Specifically, 10% of wheat that is exported from the United States passes through the four locks and dams along the Lower Snake River.

College of Idaho fisheries biologist Rick Williams said in a phone interview that he has been studying salmon and steelhead populations in the Columbia Basin for the past 35 years.

Of 100 salmon smolts that go out into the river, there need to be 2%, or at least two smolts, that survive just to replace the two adult parents. But biologists aim to see smolt survival rates in the 4% to 6% range to rebuild Chinook populations.

Right now, spring and summer chinook and summer steelhead in the Snake River are at less than a 1% smolt-to-adult ratio.

In river systems with fewer dam passages, such as the Deschutes and Yakima rivers, smolt-to-adult numbers are as high as 3.5%, Williams said.

None of the panelists at Monday’s hearing were representatives of the Nez Perce Tribes or other local Indigenous communities.

Democrats serving on the committee declined to call witnesses to the hearing and none of them attended.

“This hearing was noticed to the public and all members of the House Natural Resources Committee,” said Rebekah Hoshiko, spokeswoman for the House Natural Resources Committee, in a prepared statement. “Democrats had every opportunity to attend or send a witness to testify, but they chose not to.”

The Nez Perce spend around $22 million each year trying to preserve ocean-going species like salmon and steelhead.

Last week, members of the Nez Perce Tribe traveled to Washington, D.C. for a screening of a documentary about the 1855 treaty with the U.S. government that guaranteed their right to harvest salmon throughout their territory. That right can only be preserved, the tribe says, by breaching the dams that have turned a once fast-flowing river into a series of pools that slow juvenile fish on their journey to the ocean.

On Monday up in the northwest corner of Washington, Joel Kawahara drove to his commercial fishing boat on Neah Bay. He was headed to fish for Chinook salmon.

Kawahara, who is president of the Coastal Trollers Association, said dam removal is a form of ecosystem restoration.

“I look forward to the idea of dam removal being inclusive of everyone’s interest,” Kawahara said. “Including people that harvest the fish. Including people that use the river for other industrial means. … I think the energy issues have been overblown. There’s very little generation out of the four Lower Snake River dams this year.”

The dams were built with transportation in mind, not power. Still, the four dams produce on average 933 megawatts of power, according to a 2019 Bonneville Power Administration analysis. That’s enough to power about 750,000 homes.

In total, the dams throughout Columbia River basin produce 14,000 megawatts.

Editor’s note: This story was updated on June 27 and 18, 2023, to add additional sources.