Detroit Lake Deep Drawdown

Overview of the Detroit Lake Deep Drawdown

The City of Salem is paying close attention to the Biological Opinion issued by the National Marine Fisheries Service that requires the U.S. Army Corps of Engineers to lower the water level in Detroit Reservoir to historically low levels starting in the fall of 2026. This action aims to help young salmon migrate, as required by the Endangered Species Act. The Corps of Engineers is currently completing a Supplemental Environmental Impact Statement to study the potential effects of the drawdown on the North Santiam River and the fish and people that rely on it.

While the City supports protecting endangered fish, we are concerned about how this will affect the drinking water for about 200,000 residents and businesses in Salem and surrounding communities. The Detroit Reservoir supplies water to the North Santiam River, which is Salem’s main source of drinking water.

In the fall of 2026, the anticipated deep drawdown is expected to cause increased levels of turbidity in the river (making the river more "muddy" with dirt and suspended sediment). This will make it harder for the City to collect and treat water at the Geren Island water treatment plant, located 27 miles downstream from the Detroit Dam. Salem’s water system uses a method called slow sand filtration to treat its drinking water, but this process doesn’t work well when the water is full of dirt and sediment because the filters become quickly clogged and have to be shut down for maintenance.

The drawdown is expected to last between 30 and 60 days. During this time, 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 many weeks. During this period, we will use other water sources to meet the anticipated demand.

These alternative sources include groundwater wells on Geren Island, the Aquifer Storage and Recovery system in south Salem and an emergency supply of drinking water from the City of Keizer. However, these sources may not meet all of the expected water demand during the drawdown and recovery period. Due to this, the City is taking urgent action to improve its water system resiliency and build alternative water supply sources.

We are proud to provide high-quality, clean and safe drinking water to residents and are committed to ensuring a reliable supply of this valuable community resource.

How the City of Salem is Preparing

To prepare for these challenges, the City of Salem is taking action, including:

• Working with Others: The City is talking to the US Army Corps of Engineers and other groups in the North Santiam Watershed to explore ways to change, delay, and/or improve the drawdown plan.

• Keeping Residents Updated: The City is creating a plan to share information with residents about the situation, its effects, and what is being done to help.

• Building More Water Sources: The City is working on building new wells to increase the amount of groundwater available.

• Studying the Problem: The City is continuing to research how this drawdown will affect the water supply to be as prepared as possible.

• Water Conservation: During the drawdown, the City may ask residents to use less water to help make the supply last longer.

• Planning for Emergencies: The City is developing new water sources and making plans for quick access to more drinking water if it becomes necessary.

The City of Salem is committed to protecting endangered salmon while also making sure residents have safe drinking water. We will continue to look for solutions to this difficult situation.

Emergency Steps to Ensure a Reliable Water Supply During the Drawdown

On July 28, 2025 Salem City Council approved an emergency declaration for the upcoming drawdown. The emergency declaration allows the City to move quickly to purchase materials, equipment and services to develop new water sources and strengthen the water system before the drawdown happens. Using pre-approved contractors helps the City to move quickly to complete these crucial projects.

Immediate actions that the City is taking include:

1. Building groundwater wells at Geren Island
2. Adding a pump station to an existing connection with the City of Keizer
3. Accelerating re-sanding of the filters at Geren Island Treatment Facility prior to the drawdown to better withstand the increased turbidity in the water
4. The cost of these projects is estimated at $8 million and will come from the existing utility budget, with no additional funding from the City’s general fund.

Emergency actions are being taken proactively. We are committed to supplying reliable and safe drinking water to our residents.

Learn More

Learn more about the City of Salem's safe and clean drinking water supply at Salem's Drinking Water.

Learn more about the drawdown at Lookout Point and Green Peter reservoirs (2023) at Corps Deep Drawdown.

Read the December 2024 Biological Opinion by the National Marine Fisheries Service.

Click here to read the USACE Record of Decision that outlines how they plan to operate the Willamette Valley System of dams while they carry out these new SEIS requirements