Anticipating extra turbidity and an interruption of the clean drinking water it withdraws from the North Santiam River, the City of Salem declared a state of emergency at its City Council meeting last week. The expected turbidity is due to the U.S. Army Corps of Engineers’ deep drawdown next year of its reservoir backed up behind Detroit Dam to aid juvenile salmon and steelhead passage, particularly for salmon and steelhead listed as threatened under the federal Endangered Species Act.
Both the upper Willamette spring Chinook and the upper Willamette winter steelhead are listed as threatened under the ESA.
The City, just one of several Willamette Valley cities facing a drinking water emergency due to reservoir drawdowns in the Valley, said the declaration would “ease the process of arranging services and gathering materials and equipment essential to improving the resiliency of the City’s water system.”
The deep drawdown of Detroit Reservoir is called for in NOAA Fisheries’ December 2024 biological opinion that governs operations of the Corps’ 13 dams in its Willamette Valley system. The BiOp directs the Corps to lower the elevation in Detroit Reservoir to 1,395 feet above sea level, a level not seen since the dam was first constructed over 70 years ago in 1953, the City said in a news release. That’s about 55 feet lower than its typical fall drawdown level. The lake is full at 1,565 feet above sea level.
For NOAA’s 2024 BiOp, see https://www.fisheries.noaa.gov/resource/document/endangered-species-act-section-7a2-biological-opinion-and-magnuson-stevens-0
The Corps was initially to have begun the Detroit drawdown this year, but recently put it off until next year while it studies the action. In a recent fact sheet, the Corps said it plans to finalize a long-term management strategy for Detroit Dam and reservoir by next year. “The strategy will include considerations for fish migration and the potential of hydropower generation at the dam,” the Corps said.
In April 2025, the Corps’ Portland District completed a six-year study on the operations and maintenance of its Willamette Valley dams and reservoirs and published an Environmental Impact Statement. The EIS helps the Corps understand how its operations effect the environment, people, and ecosystems—and examines “alternatives,” or different ways the Corps could adjust operations, the Corps said in June.
However, shortly before the EIS was finalized, two new federal requirements were introduced, prompting the need for a supplemental EIS. That SEIS will evaluate:
— Implementing a deeper fall drawdown at Detroit Reservoir: To support endangered fish, as required by the NOAA Fisheries. The drawdown is not expected to occur until fall 2026, and the Corps 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 of 2024. This step is necessary to complete federal consultations and environmental compliance under NEPA.
–See CBB, June 6, 2025, Corps Extends Public Comment Period On SEIS For Willamette River Basin Dams, https://columbiabasinbulletin.org/corps-extends-public-comment-period-on-seis-for-willamette-river-basin-dams/
The City of Stayton has also taken action this year sending a letter in June to the Corps saying that the deep drawdown of Detroit Reservoir “is expected to cause prolonged and elevated turbidity in the North Santiam River—Stayton’s sole source of drinking water.”
Stayton said the expected level of turbidity from the drawdown – up to 2,700 Nephelometric Turbidity Units – would cause its slow sand water filters to stop functioning, adding that the filters work best when turbidity is lower than 10 NTUs.
“If the plant shuts down, residents could be left without clean water, or possibly any water at all, for weeks or even months,” Stayton said.
In addition, the cities of Sweet Home and Lebanon filed a $37 million lawsuit against the Corps last year over a similar drawdown of the Green Peter Reservoir in 2023, claiming that the project caused increased turbidity on the South Santiam River and damaged both cities’ water treatment systems.
That drawdown also killed thousands of kokanee salmon. The Oregon Department of Fish and Wildlife determined that the fish died from barotrauma, a condition caused by a rapid pressure reduction as fish pass from deep below the surface on one side of the dam to the other side near the surface level. Among divers, this decompression effect is known as “the bends.” Kokanee salmon, which are not endangered, are particularly sensitive to the pressure change.
The claim focuses on the Corps’ actions during a 2023 drawdown at the Green Peter Dam, which caused elevated turbidity levels in the South Santiam River, affecting the municipal water supplies of both Lebanon and Sweet Home, a City of Sweet Home press release says.
The increased sediment load severely impacted the water treatment systems of both cities, leading to heightened operational costs, equipment damage and the need for costly pretreatment system upgrades.
“The damages we’ve sustained are substantial and ongoing,” said City Manager Ron Whitlatch from Lebanon. “Together with Sweet Home, we are seeking accountability for the harm caused to our infrastructure and the significant costs we’ve incurred to ensure safe drinking water for our communities.”
In addition, both cities have also officially declared a State of Emergency in anticipation of potential impacts to water quality and both cities are working together to seek compensation for damages, which exceed $26 million in Lebanon and over $11 million in Sweet Home.
“These costs reflect the anticipated upgrades necessary of the water treatment facilities to handle current and future drawdowns, ensure long-term water safety, and address the strain the drawdowns have placed on the community’s resources,” the two cities said in a press release.
Salem says that the expected high levels of suspended sediment in the river during the drawdown will require the City to stop using river water at its water treatment plant for weeks. During that time, it will use other water sources, such as existing groundwater wells on Geren Island, the Aquifer Storage and Recovery system in South Salem and an emergency supply of drinking water through a connection with the City of Keizer. “However, these sources may not meet all of the expected water demand during the drawdown and recovery period in 2026 or the years following,” the City said.
Other projects include the construction of up to four additional groundwater wells on Geren Island and improving its filters at the water treatment plant, as well as adding a pump station to a second water connection with the City of Keizer, but these are not expected to be operational until 2027.
On the Corps’ side, it says that “while the deep drawdown of Detroit Lake has been postponed (from the fall of 2025 to the fall of 2026), the discussion surrounding its future implementation continue to raise concerns among local communities regarding water quality and supply. The USACE is committed to studying the impacts and engaging with affected residents as they develop their plans.
For background, see:
— CBB, June 6, 2025, Corps Extends Public Comment Period On SEIS For Willamette River Basin Dams, https://columbiabasinbulletin.org/corps-extends-public-comment-period-on-seis-for-willamette-river-basin-dams/
— CBB, May 23, 2025, CORPS SEEKS PUBLIC COMMENTS ON SUPPLEMENTAL EIS FOR WILLAMETTE RIVER BASIN DAMS, WANTS VIEWS ON ENDING HYDROPOWER, HTTPS://COLUMBIABASINBULLETIN.ORG/CORPS-SEEKS-PUBLIC-COMMENTS-ON-SUPPLEMENTAL-EIS-FOR-WILLAMETTE-RIVER-BASIN-DAMS-WANTS-VIEWS-ON-ENDING-HYDROPOWER/
— CBB, April 21, 2025, Corps Final EIS For Willamette Valley’s 13 Dams Selects Alternative Best For ESA-Listed Fish, Next Comes Supplemental EIS, https://columbiabasinbulletin.org/corps-final-eis-for-willamette-valleys-13-dams-selects-alternative-best-for-esa-listed-fish-next-comes-supplemental-eis/
— CBB, October 12, 2023, COURT ORDERED DRAWDOWN OF WILLAMETTE RESERVOIR TO AID ESA SALMON LEADS TO DEATH FOR THOUSANDS OF KOKANEE, HTTPS://COLUMBIABASINBULLETIN.ORG/COURT-ORDERED-DRAWDOWN-OF-WILLAMETTE-RESERVOIR-TO-AID-ESA-SALMON-LEADS-TO-DEATH-FOR-THOUSANDS-OF-KOKANEE/
–CBB, May 18, 2023, COURT ORDER HAS CORPS DRAWING DOWN TWO WILLAMETTE RESERVOIRS TO HISTORICALLY LOW LEVELS TO INCREASE JUVENILE SALMON PASSAGE, https://columbiabasinbulletin.org/court-order-has-corps-drawing-down-two-willamette-reservoirs-to-historically-low-levels-to-increase-juvenile-salmon-passage/
— CBB, March 23, 2023, Comments On Corps’ Draft EIS for 13 Willamette Valley Dams Question Whether Plan Avoids Jeopardy For ESA-Listed Salmonids, https://columbiabasinbulletin.org/comments-on-corps-draft-eis-for-13-willamette-valley-dams-question-whether-plan-avoids-jeopardy-for-esa-listed-salmonids/
— CBB, March 9, 2023, SCIENCE PANEL GIVES THUMBS-UP ON FISH RESPONSE MODELS CORPS USED TO DEVELOP DRAFT WILLAMETTE RIVER BASIN EIS, https://cbbulletin.com/science-panel-gives-thumbs-up-on-fish-response-models-corps-used-to-develop-draft-willamette-river-basin-eis/
— CBB, December 2, 2022, CORPS RELEASES DRAFT EIS FOR 13 WILLAMETTE BASIN DAMS INTENDED TO AID ESA-LISTED SALMON, STEELHEAD; DRAWDOWNS, STRUCTURAL CHANGES, LESS POWER, https://cbbulletin.com/corps-releases-draft-eis-for-13-willamette-basin-dams-intended-to-aid-esa-listed-salmon-steelhead-drawdowns-structural-changes-less-power/