For decades, the crystal-clear waters of the North Santiam River have been the source of drinking water in Salem. However, a looming environmental requirement (designed to protect Oregon’s iconic salmon) has posed a significant threat to the city’s ability to keep the taps running. This week, the City of Salem provided a major update on its "Water Supply Resilience" initiative, announcing that recent tests have surpassed expectations and put the city on a secure path toward water security.
Fish vs. Filters
The root of the issue lies 27 miles upstream at Detroit Dam. Under a federal court injunction and the Endangered Species Act, the U.S. Army Corps of Engineers is required to perform a "deep drawdown" of the Detroit Reservoir starting in fall/winter 2026. By lowering the lake level to a record-breaking 1,395 feet above sea level—55 feet lower than the typical low-water mark—officials aim to help juvenile salmon migrate downstream through lower dam outlets.
While great for the fish, the drawdown may stir up decades of accumulated silt and sediment.
Salem’s primary water treatment facility at Geren Island relies on slow sand filtration. This natural biological process is world-class at cleaning clear mountain water but is easily overwhelmed by "turbidity" (muddiness). As a result, high sediment levels can clog these filters, potentially forcing the city to halt river-water intake for weeks at a time.
The Keizer Connection
To prevent a shortage, the city has been building a redundant "backup" system. The highlight of the February 9 update was the success of a weeklong test of the newest pump station connecting Salem’s water supply to the City of Keizer.
From January 26 to January 30, city staff pulled more than 23 million gallons of water through this intertie. The test exceeded expectations, proving that Salem can successfully lean on its northern neighbors during times of crisis. This connection, combined with an existing intertie, will provide a steady flow of drinkable water even if the North Santiam becomes too turbid to treat.
Wells, Ozone, and the Path Forward
The Keizer connection is just one piece of the puzzle. The city is also:
- Drilling new wells: Four new groundwater wells at Geren Island are being outfitted and are expected to go online in July 2026, adding up to 12 million gallons per day to the city’s capacity.
- Aquifer Storage: The ASR (Aquifer Storage and Recovery) facility in South Salem acts as a "water bank," where treated water is injected underground during low-demand winter months and pumped back out during summer peaks.
- Ozone Integration: The city’s ozone treatment system, installed after the 2018 cyanotoxin event, remains a critical layer of defense. Even if water sources shift, the quality and taste remain consistent.
By diversifying its "water portfolio," Salem is making sure that when the 2026 drawdown begins, the only thing residents will notice is the success of a well-executed plan.
Links for Further Information:
- Good News for Protecting Salem’s Drinking Water Supply (City of Salem)
- City of Salem Drinking Water FAQ (City of Salem)
- Army Corps plans for more gradual Detroit Lake drawdown amid drinking water concerns (Salem Reporter)