What's happening?
Sometime after November 1, 2026, the U.S. Army Corps of Engineers will lower Detroit Reservoir to 1,425 feet in a “deep drawdown,” an operation required by a December 2024 federal Biological Opinion to protect threatened salmon and steelhead.
To get young Upper Willamette spring Chinook salmon and winter steelhead safely downstream past Detroit Dam. Lowering the lake brings them down to a lower outlet in the dam they can pass through on their way to the ocean.
The risk is turbidity. Lowering the lake can stir up sediment that has settled behind the dam, and muddy water headed downstream is a real problem for the sand-filtration drinking-water plants Salem, Stayton and other communities rely on, and for the river's ecology. The Corps calls 2026 a “step-down” year: 1,425 feet is a level the lake reached in 2015 and 2019, and later years go deeper, to 1,395 feet.
There are current legal filings between cities along the North Santiam River and the U.S. Army Corps of Engineers seeking to prevent the deep drawdown from happening.
This site brings together independent river readings, official updates, and articles to help keep the public informed.
Official 2026 timing update
Residents should come back often as the window approaches.
One connected river
From Detroit and Idanha to Salem and Turner, ten communities depend on the North Santiam watershed. Much of that water is treated with sand filtration, a proven system that works best when excess solids and silt stay low.
Choose a marker to understand a place on the river. Numbered stations show our published field samples; five USGS gauges show live provisional federal readings. Seeing both on one map makes it easier to understand what changed, where, and when.
What changed?
Published field data appears below. Draft samples remain private until an administrator reviews and publishes them. A measurement marked NA has not been run on that sample yet.
Cloudiness caused by suspended particles
Compare provisional USGS turbidity below Stout Creek near Mehama with published samples from the planned monitoring network. Toggle stations on or off to see whether a change appears in one place or travels downriver. The selected station sits above Detroit Dam while the gauge sits below it, so compare these as the two ends of the drawdown — reservoir conditions going in and river conditions coming out — not as the same water sampled twice.
Chart layers
Choose which published station records are visible.
Loading federal gauge history…
This view compares movement and timing, not equivalent measurements. USGS reports FNU and field samples report NTU; the instruments and scales are different, so a matching line does not mean the values can be compared one-for-one.
USGS · FNU | Stations · NTUWhy shared facts matter
The U.S. Army Corps of Engineers, which owns and operates Detroit Dam, plans a deep drawdown of Detroit Reservoir to give endangered salmon and steelhead safer downstream passage. Lowering a reservoir that far can stir up decades of accumulated sediment and release it into the North Santiam.
That river is not just scenery. It has been Salem's primary water supply for more than 80 years, and it is treated at Geren Island near Stayton using slow sand filtration—a naturally-driven process in use since the 1930s that depends on consistently clean source water. Sustained high turbidity is exactly the condition that process handles worst, and in a worst case it can force treatment to pause.
On July 8, 2026, the City of Salem filed a federal lawsuit against the Corps in U.S. District Court in Oregon, and has since been joined by Marion County, the City of Stayton, and the Santiam Water Control District. A central claim: the Corps never delivered a turbidity impact report owed to Congress under the Water Resources Development Act of 2024. The plaintiffs are asking the court to compel that analysis and set enforceable safeguards—like sediment thresholds that would pause or adjust the drawdown.
Latest: On October 6, 2026, U.S. District Judge Mustafa T. Kasubhai heard arguments on the plaintiffs' request for a preliminary injunction to halt the drawdown. The judge took the matter under advisement and a ruling is expected by the end of October. The Corps maintains the drawdown is a necessary Endangered Species Act measure for juvenile salmon passage and says it will not begin before November 1.
Fish passage is a genuine legal and ecological obligation, and reliable drinking water for roughly 220,000 people is a shared community need. A transparent record of turbidity from the reservoir to Jefferson gives residents, utilities, wildlife advocates, and decision-makers the same facts to work from.
Turbidity is cloudiness from suspended silt. It is not itself toxic, but it interferes with treatment and disinfection, and particles can shelter microorganisms from it. A large, sustained spike from a drawdown is a real operational problem for a river-fed slow sand plant—which is why it is the measurement the lawsuit turns on, and the one we track most closely.
Detroit and Idanha sit above the dam, so downstream turbidity does not reach their source water the same way. Gates, Mill City, Lyons, Mehama, Stayton, Jefferson and Salem draw from or near the river below it. Our stations span both sides so the difference is visible, not assumed.
The passage requirements behind the drawdown protect threatened salmon and steelhead. Clear sediment data helps communities understand whether that work is proceeding alongside dependable drinking-water treatment.
The 760-square-mile North Santiam watershed is largely undeveloped forest, which is why the water arrives clean enough for a sand filtration method. Slow sand beds clean water through a living biological layer rather than chemicals, and heavy suspended solids clog that bed—cutting flow rates, driving more frequent backwashing, and shortening how long the media lasts. Sediment is the one variable capable of undoing that advantage quickly.
Samples are organized by place, date, and measurement so residents, reporters, utilities, and river advocates can begin with the same clearly labeled information.
This page brings in live provisional readings from five U.S. Geological Survey gauges—reservoir elevation at Detroit Lake, plus flow, temperature, pH, and continuous turbidity between Niagara and Jefferson. Each value is checked against its timestamp. Readings older than four hours are withheld, including values returned from retired sensors, so stale data is never presented as current.
For your health, follow all the instructions provided by your water purveyor. They will provide you with the appropraite information you need for your specific water system.
Who this information serves
This site is built for residents, water customers, river users, and local leaders in Detroit, Mill City, Gates, Stayton, Salem, Jefferson, and Aumsville, as well as neighboring North Santiam communities. Their locations and water systems differ, but changes at Detroit Reservoir can matter across the connected watershed.
River conditions shown here are informational. Follow your local utility and public health agency for drinking-water notices and emergency guidance.
Official sources and updates
Public Health Division · USGS WaterAlert
USGS WaterAlert can notify you the moment a monitored gauge you choose crosses a turbidity level you set—so you do not need to keep checking this page during the drawdown window.
Your water deserves a clear answer
River monitoring shows what is happening across the region. Testing your own water gives you results specific to your home, well, or business—so you can understand what is there and choose your next step with confidence.
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