PORTLAND, Ore. — The U.S. Army Corps of Engineers (USACE), Portland District, will host two virtual public information sessions on Wednesday, April 1, 2026, to discuss proactive safety measures being implemented at Hills Creek Dam.
The “Interim Risk Reduction Measure” involves lowering the reservoir’s summer water level by approximately 30 feet to protect local communities from risks associated with a major earthquake from the Cascadia Subduction Zone.
During the sessions, USACE dam safety experts will explain the science behind the decision, how the dam will be operated differently, and what the community can expect regarding impacts on recreation. A question-and-answer period will follow a brief presentation.
“We want the public to understand what we’re doing and why,” said Portland District/s Dam Safety Program Manager Matt Chase. “These sessions are a chance for us to speak directly with the community and answer their questions about how this will affect them.”
While Hills Creek Dam is safe under normal conditions, recent analysis confirmed that during a major earthquake, a unique clay-and-gravel mix in the dam’s structure could weaken, causing the dam to settle. If this were to happen when the reservoir is full, it could result in water overtopping the dam. The lower summer water level is a temporary measure that will reduce this risk while a permanent solution is developed.
This action is part of a continuous program of assessment and management to ensure USACE dams protect local communities.
The public can join the meeting online or by calling in.
Virtual Public Meeting Details
📅Wednesday, April 1, 2026
Session 1:
12:30–1 p.m.
💻Join the online meeting by clicking here
📞Join by phone by calling 503-207-9433; Phone conference ID: 379 012 493#
Session 2:
6– 6:30 p.m.
💻Join the online meeting by clicking here
📞Join by phone by calling 503-207-9433; Phone conference ID: 529 300 660#
The same information will be presented at both sessions.
For more information, including current water levels and boat ramp access, please visit the Portland District’s “teacup diagrams” at: https://www.nwp.usace.army.mil/Missions/Water-Management/Teacup-Diagrams/
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BACKGROUND
Located on the Middle Fork of the Willamette River near Oakridge, Hills Creek Dam was constructed by USACE between 1956 and 1961. As a key part of the 13-dam Willamette Valley Project, the 304-foot tall rockfill dam provides flood risk management, hydropower, recreation, and other benefits to the region.
The dam sits approximately 90 miles east of the Cascadia Subduction Zone, a megathrust fault capable of producing very large, long-duration earthquakes like the one that occurred in the year 1700. The Portland District is responsible for Hills Creek Dam as part of its mission to operate 21 locks and dams across the Columbia, Willamette, and Rogue river basins.
Contact
Media Desk
503-808-4510
DLL-CENWP-MEDIA-DESK@usace.army.mil
