3 USGS Streamgages · Columbia River system
Middle Santiam River flows and levels
Middle Santiam River is gauged at 3 USGS streamgages in Oregon, each tracked by Rivermatics. The mainstem runs about 37 miles (60 km) from headwaters to outlet. It drains into the Columbia River system. Drainage area at the gauges ranges from 33 square miles at Middle Santiam River near Santiam Junction, OR up to 273 at Middle Santiam River below Green Peter Dam near Foster, OR. Rivermatics issues a daily machine-learned 14-day flow outlook at 1 of them.
Gauges on this river, upstream to downstream
Ordered by drainage area, which is how far down the river each gauge sits. April and July figures are long-term median daily flows for that month from the USGS record — historical normals, not a forecast and not today's reading.
| Gauge | State | Drainage sq mi | Elevation ft | April p50 cfs | July p50 cfs | Forecast |
|---|---|---|---|---|---|---|
| Middle Santiam River near Santiam Junction, OR | OR | 33 | — | — | 18.9 | 14-day + temp |
| Middle Santiam River near Cascadia, OR | OR | 104 | — | 754 | 121.1 | — |
| Middle Santiam River below Green Peter Dam near Foster, OR | OR | 273 | — | — | — | — |
Common questions
- How many gauges are on the Middle Santiam River?
- Rivermatics tracks 3 USGS streamgages on the Middle Santiam River, across Oregon. Each has its own page with the site's full flow record and monthly normals. The river may carry other gauges that publish neither daily values nor discharge statistics; those are not tracked here.
- Is there a flow forecast for the Middle Santiam River?
- Yes, at 1 of the 3 gauges. Rivermatics trains a machine-learned model — a temporal-fusion transformer — on each basin's observed flows, weather and snowpack, and issues a daily outlook reaching 14 days ahead: a median estimate inside a confidence band, not a single number to bet on. Every forecast is scored against days the model never trained on, and that track record is published on each gauge's live screen.
- What river system is the Middle Santiam River part of?
- The Middle Santiam River drains into the Columbia River system — it is a tributary somewhere in that chain, following the flowpath down to its terminal river. Rivermatics builds this from the USGS/geoconnex reference-mainstem network rather than from names.
- Can I use Middle Santiam River data for flood or safety decisions?
- No. Rivermatics provides estimates, not guarantees, and the readings and forecasts here may be delayed, inaccurate, or wrong. Do not use them for navigation or for any safety, rescue, or emergency decision. Check the National Weather Service and USGS directly, and use your own judgment.
Other rivers in the Columbia River system
- Snake River 31 gauges
- Willamette River 11 gauges
- Mckenzie River 9 gauges
- Big Wood River 8 gauges
- Bull Run River 6 gauges
- Cowlitz River 6 gauges
- Deschutes River 6 gauges
- Methow River 6 gauges