Are you worried about the Detroit Dam drawdown? Concerned about the North Santiam River wildlife? Anxious about your drinking water?
We aggregate the data so you don't have to. Monitor the water quality of the North Santiam River from Detroit Lake to Jefferson—making changes in sediment, dissolved solids, temperature, and pH visible to the communities who love this tributary.
Monitoring corridor
The lower North Santiam River, also known as the North Santiam Watershed, serves the cities of Detroit, Gates, Idanha, Jefferson, Lyons, Mehama, Mill City, Salem, Stayton, and Turner as a drinking water source. This water is treated using a sand filtration system that is sensitive to high solids and silt.
Select a marker to inspect the latest sample. Our numbered stations sit alongside five live USGS gauges, so independent sampling and federal monitoring can be read on the same river at the same time.
Weekly trend explorer
Cloudiness caused by suspended particles
Our weekly grab samples at Detroit Lake plotted against the continuous USGS turbidity gauge below Stout Creek, near Mehama. This station sits above Detroit Dam while the gauge sits well below it, so read these as the two ends of the drawdown — reservoir conditions going in, river conditions coming out — not as the same water sampled twice.
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Units differ by method and are not interchangeable: the USGS sensor reports FNU (infrared light) while lab turbidity is reported in NTU (white light). They track closely on the same water but can diverge, so the two series are labeled separately rather than merged into one number.
Gauge 14183020Why this project exists
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. A central claim: the Corps never delivered a turbidity impact report owed to Congress under the Water Resources Development Act of 2024. Salem is asking a court to compel that analysis and set enforceable safeguards—like sediment thresholds that would pause or adjust the drawdown.
Both sides of this are real. Fish passage is a genuine legal and ecological obligation, and so is the drinking water of roughly 220,000 people. That tension is what the court is now weighing—and it is being decided on turbidity numbers. So we publish turbidity numbers, from the reservoir to Jefferson, where anyone can see them.
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 exist to protect threatened salmon and steelhead. Publishing sediment data is not opposition to that—it is the evidence needed to do it without putting a capital city's filtration in a position it cannot manage.
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.
Weekly field samples, organized by place, date, and measurement—kept in the open so residents, reporters, and canyon water operators are reading the same record rather than rumors.
Alongside our own sampling, this page streams live readings from five U.S. Geological Survey gauges on the corridor—reservoir elevation at Detroit Lake, and flow, temperature, pH and continuous turbidity between Niagara and Jefferson. Two independent records make the trend far harder to dismiss than either one alone. One caution shapes how we display it: the federal system still returns readings from retired sensors, including a turbidity value at Niagara last measured in 2016. Every number here is checked against its own timestamp, and anything older than four hours is withheld rather than dressed up as current.
A treatment challenge is not the same as unsafe water. Utilities monitor continuously and are required to notify the public if standards are not met. This project adds regional context and early visibility—for health, boil-water, or emergency decisions, follow your own water provider and public health agencies, not social media.
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