SALEM, Ore. — Marion County says it will immediately appeal a federal judge’s decision allowing the U.S. Army Corps of Engineers to move forward with plans to significantly lower water levels at Detroit Lake this fall.
The county announced Wednesday, November 4, that it will take the case to the U.S. Court of Appeals for the Ninth Circuit after U.S. District Judge Mustafa T. Kasubhai denied its request for a preliminary injunction blocking the planned drawdown.
Marion County is also asking the appeals court to issue an emergency injunction while the appeal is considered.
“We are extremely disappointed in today’s decision, but this fight is far from over,” said Marion County Commissioner and Chair Colm Willis. He argued that the Army Corps’ plan threatens drinking water supplies, agriculture, fish populations and communities along the canyon.
The judge’s ruling does not resolve the underlying lawsuit, but it allows the Army Corps to proceed with the first year of its new policy calling for annual deep drawdowns of Detroit Lake.
Under the plan, the reservoir would be lowered to its lowest historic level during the first year, with even deeper drawdowns planned in subsequent years.
Marion County argues the Army Corps has not completed a legally required turbidity report evaluating potential water-quality impacts before proceeding with the plan.
The county also points to problems associated with a similar drawdown at nearby Green Peter Lake in 2023. That operation resulted in significant increases in water turbidity and the deaths of thousands of salmon, according to the county.
Concerns Over Drinking Water and Fish
County officials say lowering Detroit Lake below its minimum conservation pool could disturb sediment on the reservoir bottom, increasing turbidity and potentially affecting downstream drinking water systems and fish populations.
The county estimates the proposed drawdowns could threaten water supplies serving more than 220,000 people, including residents, hospitals, schools, businesses and agricultural operations downstream.
Officials also warn that reduced reservoir levels could create water shortages if rainfall is insufficient to refill the lake, potentially affecting communities, farmers and the local recreation and tourism economy.
Marion County cites the Army Corps’ own analysis indicating that conditions involving low rainfall and deep drawdowns could result in water shortages approximately one out of every four years.
The county also raised concerns about the potential for unusually dry conditions during the coming months, citing NOAA’s October-December 2026 forecast for a potentially strong El Niño continuing into early spring 2027.
Background of the Lawsuit
Marion County filed its lawsuit against the U.S. Army Corps of Engineers on May 13, 2026, seeking to stop the planned drawdowns until the agency completes a required turbidity report and provides an opportunity for meaningful public comment.
Congress required the Army Corps to evaluate lessons learned from water-quality problems associated with the Green Peter Lake drawdown.
The county contends the agency missed its legal deadline for completing that evaluation by more than four months.
On August 11, Marion County filed its motion for a preliminary injunction, arguing the federal government violated the law when it adopted the new policy of annual deep drawdowns at Detroit Lake.
Wednesday’s decision means the Army Corps can proceed with its planned 2026 drawdown while the legal challenge continues.
Marion County says it will continue pursuing the lawsuit in federal district court in an effort to prevent an even deeper drawdown planned for fall 2027.
The county maintains that protecting Detroit Lake is critical to maintaining clean drinking water, supporting downstream communities and agriculture, preserving fish populations and protecting the region’s environment and economy.
