The Willamette River runs brown with a heavy sediment resulting from the draw down of Lookout Point Reservoir. Lane County, Eugene Oregon. In September 2021, the U.S. District Court for the District of Oregon issued an interim injunction in Northwest Environmental Defense Center et al. v. U.S. Army Corps of Engineers, requiring the U.S. Army Corps of Engineers (USACE) to change operations at several Willamette Valley dams, including deep seasonal drawdowns of reservoirs. This injunction addressed urgent concerns under the Endangered Species Act (ESA), specifically the survival and downstream passage of threatened Upper Willamette River spring Chinook salmon and winter steelhead. The court found that USACE and the National Marine Fisheries Service (NMFS) had failed to implement several “Reasonable and Prudent Alternatives” (RPAs) mandated by a 2008 NMFS Biological Opinion, which had determined that inadequate fish passage and degraded water quality at valley dams were causing ongoing ESA violations. As remedies, USACE was ordered to immediately implement interim operational measures—such as reservoir drawdowns, increased spillway flows, and delayed refilling—while more permanent solutions were planned. Under the injunction, USACE must perform “deep drawdowns” at multiple reservoirs every fall, lowering water levels close to the dam’s regulating outlets (within ~25 ft) to enhance volitional downstream passage for juvenile salmonids. Specific targets include:
Cougar Reservoir: ~27 ft drawdown from November 15 to December 15
Fall Creek: ~43 ft drawdown from December 1 to January 15
Lookout Point: ~75 ft drawdown from November 15 to December 15
Green Peter: ~142 ft drawdown from November 15 to December 15
These drawdowns are expected to continue annually until a new Biological Opinion is finalized (targeted for December 2024). The court established a scientific expert panel to refine implementation details, ensuring drawdowns prioritize fish safety and use of regulating outlets rather than turbines. Biannual compliance reports and ongoing fish passage monitoring are also required. This injunction reprioritizes hydropower and recreation in favor of ecological protection. It signaled USACE’s legal obligation to manage reservoir operations under the ESA, expanding its discretionary authority—even when operations temporarily reduced hydropower output—while remaining consistent with authorizing legislation. The 2021 injunction legally compelled USACE to implement targeted drawdowns, increased spill, and delayed reservoir refills to address threatened fish passage and water quality. Rooted in ESA obligations and enforced through judicial oversight, these interim measures aim to mitigate “irreparable harm” to salmonids while a refined, long-term operational plan is developed.
Autumn, Eugene Oregon, Lane County, Willamette River, Willamette Valley
