PORTLAND, Ore. — The U.S. Army Corps of Engineers (USACE), Portland District, has finalized its plan for operating the Willamette Valley’s 13 federal dams by executing a Record of Decision (ROD).
The ROD enables USACE to implement operational changes to support Upper Willamette River Chinook salmon and winter steelhead while also delivering congressionally authorized flood risk management, hydropower, recreation, and water quality benefits.
“The Environmental Impact Statement (EIS) and supplemental EIS outline operational and structural actions USACE considered, including environmental impacts that informed decision-making,” said Alan Davis, Portland District public affairs chief. “This data-driven decision effectively modernizes dam operations and fulfills USACE’s environmental responsibilities.”
The plan includes the following immediate actions:
- Detroit Reservoir Drawdown: A phased, deep fall drawdown for safe salmon passage, actively managed to protect downstream water quality and ensure a reliable summer refill.
- System-Wide Adjustments: Seasonal drawdowns, targeted water-spills, and fish-weir operations at key facilities.
- Continued Hydropower: Uninterrupted execution of the dams’ federal hydropower mission.
- Endangered Species Act Consultation: Reinitiating formal consultation with the National Marine Fisheries Service to develop long-term operational strategies.
To immediately support endangered species needs, USACE is implementing tailored operations at key facilities across the Willamette Valley:
- Green Peter: Deep fall drawdown and spring spill to guide downstream migration.
- Lookout Point: Deep late-fall drawdown and spring spillway usage to provide volitional passage.
- Cougar: Deep late-fall drawdown followed by a delayed spring reservoir refill.
- Foster: Delayed spring refill and utilization of a specialized summer attraction-flow fish weir.
- Hills Creek: Prioritized nighttime winter water releases to align with natural wild fish migration.
- Big Cliff: Spill spreading across multiple bays to reduce total dissolved gas levels and improve downstream water quality.
About the Record of Decision
The ROD serves as the final agency decision, combining fish-passage and water-quality operations developed in the 2025 Willamette Valley System Operations and Maintenance EIS with the targeted Detroit Reservoir analysis completed in the May 2026 supplemental EIS. The complete ROD is available on the Willamette Valley System EIS webpage.
About USACE in the Willamette Valley
USACE operates and maintains 13 dams in the Willamette River Basin, preventing an estimated $500 million in flood damages annually. These facilities provide vital flood risk management, hydropower, irrigation, and recreation opportunities while supporting regional fish and wildlife.
Release no. 26-024