The lower Snake River has returned to the top of a environmental group’s annual report of the nation’s 10 most endangered waterways after an absence of several years.

American Rivers named the lower Snake the most endangered river in 2021, citing the threat the four lower Snake River dams pose to the continued existence of wild salmon and steelhead runs and the harm their loss would inflict on Native American tribes, fishing communities and ecosystems.

The lower Snake was last on the list in 2009 when it was named the third-most imperiled river. It landed at the top of the list in 1999 and 2000 and has appeared on the list a handful of other years, each time because of dams and the harm they cause salmon and steelhead.

Rivers on the list face specific threats. But they are chosen in part because of pending human decisions that could either help mitigate those threats or see them come to pass.

The lower Snake River returned to the list because of Rep. Mike Simpson’s proposal to save salmon and steelhead by breaching Lower Granite, Little Goose, Lower Monumental and Ice Harbor dams in eastern Washington. His $33 billion concept calls for investments to replace the lost hydropower, help farmers get their crops to market without barge transportation and aid for communities like Lewiston and Clarkston to adjust to life without slackwater. It would also institute a moratorium on salmon-related lawsuits at remaining dams in the basin and extend their federal operating licenses by up to 50 years. Simpson argues it would end what he calls the salmon wars and provide certainty to the region.

Breaching the dams, an idea that has been debated for more than two decades, would return the lower Snake to a free-flowing river, which would allow juvenile salmon and steelhead to reach the ocean sooner, mitigate water temperatures during the warmest parts of the year and make the waterway less hospitable to some predators. Many fisheries scientists say the change would allow the fish to hit survival rates sufficient to reverse long-term declines and slowly lead to recovery.

But breaching would end tug-and-barge shipping of grain on the river, reduce the regional production of hydropower and make irrigation near the Tri-Cities more difficult and expensive.

American Rivers has endorsed the Idaho Republican’s concept, which could be included in a massive infrastructure bill later this year.

“We’re facing a critical choice on the Snake River. We can either stay with the status quo, which means failing salmon runs, more costly litigation, increasing energy insecurity and broken promises to tribes,” said Tom Kiernan, president of American Rivers. “Or we can choose to invest in salmon recovery and infrastructure solutions that create a future of abundance and prosperity for the region. We think the choice is clear and we’re calling on the Northwest congressional delegation to take action now.”

Simpson introduced his plan in February and it faces an uncertain future. None of the powerful Democratic senators or representatives from Washington and Oregon that he was counting on for help have backed the plan. Some Republicans like Reps. Cathy McMorris Rodgers and Dan Newhouse of Washington and Russ Fulcher of Idaho and Sen. Jim Risch of Idaho are opposed to the plan.

Regional stakeholders including tribes, local governments, conservation organizations, fishing groups, and agriculture and shipping representatives have written letters both for and against the idea.

Other rivers on the list include the following: 2, Lower Missouri River (Iowa, Kansas, Missouri, Nebraska); 3, Boundary Waters (Minnesota); 4, South River (Georgia); 5, Pecos River (New Mexico); 6, Tar Creek (Oklahoma); 7, McCloud River (California); 8, Ipswich River (Massachusetts); 9, Raccoon River (Iowa); 10, Turkey Creek (Mississippi).

Barker may be contacted at ebarker@lmtribune.com or at (208) 848-2273. Follow him on Twitter @ezebarker.