Judge allows Detroit Lake drawdown, county plans appeal

A federal judge denied Marion County and Salem’s request to block the Army Corps of Engineers from carrying out a deep drawdown of Detroit Lake, finding they had not shown that irreparable harm to regional water supplies was likely. The Corps plans to lower the reservoir this fall to help threatened salmon pass Detroit Dam, as required by a separate court order. Local governments say the drawdown could send sediment downstream, disrupt drinking-water and other water uses, and harm fish; they cite problems during a 2023 drawdown at nearby Green Peter Reservoir and also argue the Corps has not completed a required turbidity study. The judge noted that the Corps has an emergency plan to pause the drawdown if evidence shows drinking water or regulatory requirements are at risk. Marion County says it will appeal and seek an emergency injunction, while the ruling allows the Corps to proceed for now.