PORTLAND, Ore. -- The U.S. Army Corps of Engineers (USACE), Portland District, is accepting public comments May 16 through June 6 as part of a Supplemental Environmental Impact Statement (SEIS) focused on two new requirements related to the operations and maintenance of the Willamette Valley System of dams and reservoirs:
- Implementing a deeper fall drawdown of Detroit Reservoir
- Studying a permanent end to hydropower production at Willamette Valley dams
“As part of the National Environmental Policy Act process, we collect public comments to help us shape what we study in the SEIS – we call this process public scoping,” said Liz Oliver, the Portland District project manager leading the SEIS process. “Comments will help USACE better understand how these proposed changes may affect communities, the environment and reservoir users.”
USACE will accept comments via email or mail, or in person at public scoping comment sessions via written comment cards.
Email: willamette.eis@usace.army.mil
Mail: U.S. Army Corps of Engineers
Attn: CENWP-PME-E / Willamette EIS
P.O. Box 2946
Portland, OR 97208-2946
Public Scoping Comment Sessions:
Virtual Meetings – visit https://www.nwp.usace.army.mil/WVS-EIS/ for log-in information
Wednesday, May 28 • 6-7 p.m.
Thursday, May 29 • noon to 1 p.m.
In-Person Meetings
Saturday, May 31 • 10 a.m. to noon
Detroit City Hall
345 Santiam Ave.
Detroit, Oregon 97342
Tuesday, June 3 • 6-8 p.m.
Broadway Commons
1300 Broadway St. NE
Salem, Oregon 97301
Background
In April 2025, Portland District completed a six-year study on the operations and maintenance of the Willamette Valley System of dams and reservoirs and published an Environmental Impact Statement (EIS). The EIS helps USACE understand how its operations effect the environment, people, and ecosystems—and examines “alternatives,” or different ways USACE could adjust operations. Shortly before the EIS was finalized, two new federal requirements were introduced. These additions prompted the need for a SEIS, which is now open for public scoping.
What the SEIS Will Cover
USACE prepares a Supplemental Environmental Impact Statement when significant new information or requirements come up that need additional analysis and public input. This SEIS will evaluate:
- Implementing a Deeper Fall Drawdown at Detroit Reservoir
In December 2024, the National Marine Fisheries Service issued a Biological Opinion that requires USACE to perform a deeper fall drawdown at Detroit Reservoir to support endangered fish. The drawdown is not expected to occur until fall 2026, and USACE will evaluate its effects—such as potential impacts to water quality and local communities—in the SEIS.
- Ending Hydropower Production at Willamette Valley Dams
In December 2024, Congress passed the Water Resources Development Act (WRDA) of 2024, which directed USACE to study an additional alternative that would remove hydropower as an authorized purpose and end hydropower operations at some Willamette Valley dams. This step is necessary to complete federal consultations and environmental compliance under NEPA.
Because these two requirements came late in the EIS process, USACE finalized and published the EIS and issued an interim Record of Decision for operations while the SEIS is developed. For more information on the EIS or the SEIS, visit https://www.nwp.usace.army.mil/WVS-EIS/