City Asks Corps to Take Additional Steps to Safeguard Salem’s Water in 2026 as Detroit Reservoir Drawdowns Begin

The City of Salem is asking the U.S. Army Corps of Engineers to include additional safeguards as it continues to plan for annual deep drawdowns of the Detroit Reservoir to improve downstream passage of Endangered Species Act-protected fish beginning later this year. The drawdowns will result in high levels of turbidity, which creates significant risk to the City's drinking water treatment plant as it draws water from the North Santiam River downriver from the Detroit Reservoir.

The Corps' current plan addresses many of the concerns City staff have expressed since learning of the planned drawdowns last January, including significant commitments such as beginning the drawdowns closer to late November or early December when the demand on Salem's water supply is lower, conducting the drawdowns in a series of deeper steps over several years to gauge drinking water impacts, and limiting the drawdowns duration to two weeks.

However, City staff remain concerned about the absence of turbidity triggers - ways to identify corrective actions depending on levels of murkiness in the water. Turbidity will make filtration difficult or impossible. Accompanying action measures are missing from the Willamette Valley System Operations and Maintenance Draft Supplemental Environmental Impact Statement issued by the Corps of Engineers in November 2025.

"The purpose of the turbidity trigger is to protect human health, the City's residents and businesses who rely on Salem to provide safe drinking water, and to protect the City's water treatment system," said Krishna Namburi, Salem city manager. "It is critical that the Corps include a plan of action for how they will adjust their drawdowns if turbidity is too high to provide safe drinking water."

This recommendation is based on years of operational experience coupled with scientific research conducted over the past year.

"Clear triggers and actions are essential for the City's operational and contingency planning," Namburi said in the Jan. 13, 2026, letter. "Establishing mutually acceptable triggers and action measures also represents the best way forward for providing assurances to our current and future regional customers that safe drinking water will continue to be reliably delivered."

The City of Salem remains committed to working with the U.S. Army Corps of Engineers and others to evaluate and implement measures that support downstream passage of juvenile fish species, protect habitat and water quality, ensure water demands are met, and provide for the many users of the North Santiam River.

The drawdown of Detroit Reservoir is detailed in a Biological Opinion issued by the National Marine Fisheries Service in December 2024 as required by the Endangered Species Act. The opinion directs the U.S. Army Corps of Engineers to lower the elevation in Detroit Reservoir to a level not seen since the dam was built over 70 years ago.

The purpose of the deep drawdowns is to improve downstream passage of ESA-protected fish. However, the drawdowns will also result in high levels of suspended sediments - fine particles of clay, silt and other matter - in the North Santiam River downstream of the dam. High levels of suspended sediment over an extended period of time present a significant risk to the operation of the City's water treatment plant, which draws water from the North Santiam River at its location on Geren Island.

High levels of suspended sediment in the intake water will require the City to stop using river water at its water treatment plant, possibly for several weeks. During this period, the City will use other water sources to meet the anticipated demand. These alternative sources include existing and new groundwater wells on Geren Island, the Aquifer Storage and Recovery facility in South Salem, and an emergency supply of drinking water through a connection with the City of Keizer. These sources should meet the expected water demand during the drawdown and recovery period in 2026.

Over the past year, the City has taken several steps to prepare for the drawdowns. These include declaring an emergency in July 2025 to allow staff to expedite the construction of additional groundwater wells at Geren Island, adding an additional pump station connection with the City of Keizer and accelerating filter re-sanding to better withstand above-normal turbidity.

New measures will not only increase our alternate supply for the drawdown, but also will make our drinking water system more resilient in the face of other disruptions, such as the recent flooding.

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