PORTLAND, Ore. – The U.S. Army Corps of Engineers’ (USACE) Portland District has extended the public comment period from June 6 to June 21 for its 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.
“As part of the National Environmental Policy Act (NEPA) 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. “Because these proposed changes are important, we want to make sure everyone has enough time to share their thoughts. Extending the deadline gives more people a chance to participate and helps us make better, more informed decisions.”
The SEIS will evaluate:
Implementing a deeper fall drawdown at Detroit Reservoir: To support endangered fish, as required by the National Marine Fisheries Service. 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.
Studying a permanent end to hydropower production at Willamette Valley dams: As directed by Congress in the Water Resources Development Act (WRDA) of 2024. This step is necessary to complete federal consultations and environmental compliance under NEPA.
USACE will accept comments via email or mail through June 21.
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
More information, including a video of a previous public scoping comment sessions, is available at https://www.nwp.usace.army.mil/WVS-EIS/
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.