Detroit Lake Deep Drawdown Delayed Till Next Year: Report

Temporary good news for Willamette Valley kokanee anglers: The Army Corps of Engineers is delaying their super-deep drawdown of Detroit Lake from this fall to late 2026.

That’s according to a report this morning in the Salem Statesman-Journal, which adds that the Corps will use the time “to listen to what impacted people have to say about this drawdown.”

The federal agency’s plans to drain the reservoir to its lowest level ever is meant to help downstream-migrating young spring Chinook and winter steelhead smolts get through Detroit Dam, but doing so will suck many kokanee out of the impoundment too, if what happened in fall 2023 at Green Peter Reservoir for the same reason is any indication.

The Green Peter drawdown also led to water quality issues in downstream towns as their systems struggled to deal with all the sediment, and there are fears that doing the same at Detroit could impact the drinking water of 200,000 people, according to outdoor reporter Zach Urness, who has been all over this story.

In our Big Pic Feature in the current issue of Northwest Sportsman, kokanee angler Tom Schnell raises alarm bells about the Corps’ plans at Detroit. “(What) we have seen from Green Peter was devastating. It was an ecological disaster. It was an environmental disaster. It was a socioeconomic disaster. They want us to believe that Detroit will be different. What can be certain is it will devastate, and possibly even destroy, one of the best kokanee fisheries in Oregon.”

Urness quotes the Corps’ lead fish biologist as stating that they “do expect a significant number of kokanee to be passed out of the reservoir,” though there’s hope it won’t be as bad as Green Peter because of the depth of the drawdown.

Due to a long-running court case over impacts of the Corps’ Willamette Valley dams to Endangered Species Act-listed springers and winter-runs, the federal agency is legally obligated to help more young fish get past their dams. Adults are trapped and trucked around the obstructions to access upstream spawning grounds. The outmigrating smolts swim close to the surface, but there is no surface collector like on dams on Washington’s North Fork Lewis and Baker Rivers, so the idea is to lower reservoirs so the fish can access low-level output tunnels.

According to the National Marine Fisheries Service, “The lack of passage around most dams forces other populations to spawn at lower elevations. This makes them more vulnerable to development impacts and climate change, which will put them at higher risk of extinction by about 2040.”

Stay tuned.