Protecting Wild Salmon in the Willamette: Your Guide to the Draft SEIS

The Army Corps of Engineers, Portland District, has released a Draft Supplemental Environmental Impact Statement (Draft SEIS) on their analysis of two options in the Willamette River Valley System:

1. Ending hydropower at all 13 dams

2. Conducting a deeper drawdown at Detroit Dam Reservoir

The public comment period is now open now through December 29th, 2025, and we are urging members to submit comments to the Corps. Please see the top findings below and guidance on how to respond.

This is an opportunity to raise our voices to protect native salmon and the ecological balance of our region, while demanding that Oregonians stop paying for a costly hydropower operation that produces a fraction of power.

Below is an overview of key findings, background, and how you can take action!

Key Findings from the Corps’ Statement:

• A deep drawdown of Detroit Reservoir will enable more effective fish passage

  • The Corps proposes to conduct an annual deep drawdown in the late fall so that juvenile fish can migrate effectively through the dam and downstream. In order to reduce the impact on downstream water quality, the Corps will be phasing the drawdown over three years. This stepwise approach, combined with the relatively small area of reservoir floor that will be exposed, will minimize the impacts of sedimentation downstream while giving outmigrating fish a chance to head towards the ocean.
    

• The SEIS fails to consider what is possible to help fish if commercial hydropower is eliminated

  • The scope of what was analyzed by the Corps was too narrow. The agency failed to consider the full range of reasonable possibilities for operating the dams to recover fish and reduce the likelihood of needing to build expensive and ineffective fish collection facilities. This includes a lack of analysis of changes to deep drawdown timing and the removal of reregulation dams (these are facilities solely used in the production of hydropower).
    

• The new alternative only analyzes ending federal operations to generate hydropower – all other dam purposes remain intact – but this would require infrastructure modifications.

  • The alternative maintains the remaining authorizations of flood control (flood risk management), fish and wildlife, recreation, navigation, irrigation, municipal and industrial water supply, and water quality. But to safely operate the dams without hydropower requires a retrofit of the dam to remove the hydropower infrastructure, reconfigure the penstock, and place something like a cone valve on the outlet

Background on the Supplemental EIS

This additional analysis comes after the Corps completed a six-year study on the Willamette Valley dams earlier this year. Shortly before finalizing the EIS, released in April 2025, new developments prompted a supplemental study. Here’s a breakdown of the two new requirements and the reason for each:

• Studying a permanent end to commercial hydropower production at the Willamette Valley dams: In December 2024, Congress passed the Water Resources Development Act (WRDA) of 2024, which directed USACE to look at a new option, or “alternative,” that would remove hydropower at Willamette Valley dams.
  

• Implementing a deeper drawdown at Detroit Reservoir in 2026: The National Marine Fisheries Service (NMFS) published a Biological Opinion in December 2024. That opinion directed the Corps to implement a deeper fall drawdown at Detroit Reservoir to support fish passage.
  

The Threat of Hydropower:

Hydropower at the Willamette River Basin dams is killing salmon and losing money—to the tune of nearly a billion dollars by the Corps’ own analysis. These dams generate less than 2% of the power in the Federal Columbia River Power system, and they are responsible for blocking 75% of access for salmon and steelhead.

The cost, which falls on Oregon families and businesses, combined with waste, which is minimal power, is not worth pushing native salmon to the brink of extinction. (Federal fisheries managers predict that Willamette salmon could go extinct by 2040 if we don’t take action.)

Because of the threat to salmon, and the wasteful spending, Congress passed WRDA 2024 to require the Corps to evaluate an alternative operation.

The Need for Seasonal Drawdowns:

Deep drawdowns are a low-cost, effective solution to save salmon, maintain flood control, and return our rivers to a more natural flow.

For salmon, drawdowns allow juvenile fish to migrate successfully through the dams by temporarily lowering the water level closer to passage routes far down on the dams. Without drawdowns, very few juvenile salmon make it to the dams or survive the treacherous trip through the power turbines on their journey to the ocean. And after failing to address the problem for decades – to the detriment of the salmon population – the Corps was forced to conduct drawdowns at more dams to improve fish passage. The results have been promising.

While all dams are different and scientists are working to adjust the drawdown methods for specific dams, studies indicate that deep drawdowns at Fall Creek, where drawdowns have been happening for over a decade, led to a 98-99% survival rate for out-migrating juvenile Chinook salmon and resulted in roughly a ten-fold increase in returning adult salmon. This low-cost solution does not require dam removal and has successfully increased juvenile passage and survival through Fall Creek Dam.

Drawdowns are also critical for maintaining flood control, the original purpose of the dams, while restoring our rivers to a more natural flow and preserving Oregon’s ecological balance.

Our Goal:

Native Fish Society’s goal, in partnership with Tribal Nations like Grand Ronde and other environmental organizations, is to help our native salmon and steelhead recover and restore more natural function to our rivers in the Willamette Valley. Through changing how the dams are operated, we can save native fish and hundreds of millions of dollars in taxpayer money. 

How is NFS working to achieve our goal?

Native Fish Society is fighting to recover Oregon's most imperiled wild fish by building a groundswell of public support to advocate for effective fish passage at the 13 federally owned and operated dams in the basin.

We are holding the management agencies accountable in court, assuring that they take action now to provide relief to struggling populations and ensuring that they develop and implement a long-term plan to recover the species.

How You Can Stay Involved:

Start by submitting a comment during this critical period! Your voice can help protect wild fish and ensure the Corps considers real, science-based solutions.

Congress demanded that the Army Corps of Engineers study an alternative operation at the Willamette River Basin dams, given the nonsensical results of hydropower – i.e. destruction of native salmon, at an astronomical cost to Oregonians, for less than 2% of power generated … And now is our chance to speak loud and clear.

You can help make a difference by telling the Corps that it’s time to take a new approach.

If you’re looking to get even more involved, please send us a message. We’ll let you know about any volunteer opportunities and/or future “Action Alerts” to take action. 

Let’s protect the health of our waterways by restoring native salmon, while saving money and a key part of our culture. 

For more background information, view our FAQs on Willamette River Basin reservoir drawdowns originally published in fall 2024.