A planned deep drawdown of Detroit Lake in fall 2026 is drawing formal objections from the City of Salem and Marion County, which argue the U.S. Army Corps of Engineers has not adequately addressed risks to downstream drinking water treatment, turbidity and fish mortality. The dispute centers on a federal effort to improve fish passage at Detroit Dam while limiting harm to communities that depend on the North Santiam River.
The Corps is studying the deeper drawdown as part of a Supplemental Environmental Impact Statement tied to a 2024 Biological Opinion from NOAA Fisheries. According to the Corps, that opinion requires a deeper fall drawdown at Detroit Reservoir to support endangered fish moving through the dam. The drawdown is not expected until fall 2026, and the agency has said the environmental review is intended to evaluate effects on water quality, local communities and dam operations.
Salem’s concern is not that taps would automatically run dry. The city’s position is narrower and more credible than that: officials say high turbidity from suspended sediment could make river water too difficult to treat at the Geren Island plant for a period of time, forcing Salem to rely on backup sources instead. In a Jan. 13 statement, the city said the Corps’ updated approach addressed some earlier concerns by moving the drawdown later in the year, limiting the lowest drawdown period to two weeks and taking the operation in deeper steps over several years. But Salem said the plan still lacks clear turbidity triggers and required corrective actions if conditions become too severe for safe treatment operations.
City Manager Krishna Namburi said those triggers are needed to protect both public health and the city’s treatment system. Salem said that if sediment levels remain too high, it may need to stop using river water for several weeks and shift to other sources, including existing and new groundwater wells on Geren Island, the Aquifer Storage and Recovery facility in South Salem and an emergency intertie with Keizer. The city added that those alternative sources should be enough to meet expected demand during the drawdown and recovery period in 2026.
Marion County’s objections have focused first on process and analysis. In a Jan. 6 letter summarized by the county, officials argued a turbidity report required by federal law had not yet been completed and said the public could not meaningfully evaluate the Corps’ draft SEIS without it. The county also said earlier comments raised concerns about potential sediment impacts to downstream drinking water systems serving more than 200,000 residents.
The county later expanded its challenge to include fish mortality, warning of a possible kokanee die-off if Detroit Lake is drawn down too deeply. County officials pointed to the 2023 Green Peter Reservoir event, where more than 1 million kokanee were reported killed, and argued the Corps’ draft analysis does not fully account for similar risks at Detroit. That claim remains an argument from the county, not a settled finding for Detroit Lake, and it is one of the areas where the Corps’ direct response will matter most.
What the conflict now turns on is not whether the drawdown is controversial. It clearly is. The harder question is whether the Corps can satisfy endangered-species requirements while adding enough operational safeguards to reassure Salem, Marion County and other downstream communities that the plan will not create avoidable harm.
