Salem Urges Army Corps to Add Drinking Water Safeguards to Detroit Reservoir Drawdowns

Salem, OR. — The City of Salem is asking the U.S. Army Corps of Engineers to include additional safeguards as it plans annual deep drawdowns of Detroit Reservoir to improve downstream passage of Endangered Species Act–protected fish beginning later this year.

City officials warn the drawdowns will significantly increase turbidity—murkiness caused by suspended sediments—in the North Santiam River, posing a serious risk to Salem’s drinking water treatment plant, which draws river water downstream at Geren Island.

While the Corps’ current plan addresses several long-standing city concerns, including scheduling drawdowns for late November or early December when water demand is lower, limiting the duration to two weeks, and phasing deeper drawdowns over multiple years, Salem officials say critical protections are still missing.

Specifically, City staff are seeking turbidity “triggers” tied to clear corrective actions if sediment levels become too high to safely treat drinking water. These triggers and response measures are not included in the Willamette Valley System Operations and Maintenance Draft Supplemental Environmental Impact Statement issued by the Corps 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 Salem City Manager Krishna Namburi. “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.”

Namburi said the City’s recommendation is grounded in years of operational experience and scientific research conducted over the past year. In a January 12, 2026 letter, he emphasized that clear triggers and action measures are essential for Salem’s operational and contingency planning and for assuring current and future regional customers that safe drinking water will remain reliable.

The City says it remains committed to working collaboratively with the Corps and other partners to support fish passage, protect habitat and water quality, meet water demands, and serve the many users of the North Santiam River.

The planned drawdowns are detailed in a Biological Opinion issued in December 2024 by the National Marine Fisheries Service, as required under the Endangered Species Act. The opinion directs the Corps to lower Detroit Reservoir to levels not seen since the dam was built more than 70 years ago to improve downstream passage of juvenile fish.

However, those deep drawdowns are expected to release large amounts of fine sediment—such as clay and silt—into the river. Extended periods of high suspended sediment could force Salem to stop using river water at its treatment plant for weeks.

During such periods, Salem plans to rely on alternative water sources, including existing and newly constructed groundwater wells on Geren Island, the Aquifer Storage and Recovery facility in South Salem, and an emergency drinking water connection with the Keizer. City officials say these sources should meet expected demand during the 2026 drawdown and recovery period.

Over the past year, Salem has taken multiple steps to prepare, including declaring an emergency in July 2025 to expedite new groundwater well construction, adding an additional pump station connection with Keizer, and accelerating filter re-sanding to better withstand elevated turbidity.

City officials note that these investments not only expand Salem’s alternate water supply for the drawdowns, but also strengthen the overall resilience of the drinking water system against other disruptions, including flooding.

More information about Salem’s drinking water system is available at CityofSalem.net/drinking-water.