7 USGS Streamgages
Chehalis River flows and levels
Chehalis River is gauged at 7 USGS streamgages in Washington, each tracked by Rivermatics. The mainstem runs about 131 miles (211 km) from headwaters to outlet. Drainage area at the gauges ranges from 113 square miles at Chehalis River near Doty, WA up to 1,780 at Chehalis River near Montesano, WA. The gauged reach falls about 298 feet, from 307 feet down to 10. Rivermatics issues a daily machine-learned 14-day flow outlook at 4 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 |
|---|---|---|---|---|---|---|
| Chehalis River near Doty, WA | WA | 113 | 307 | 432.8 | 59.2 | 14-day |
| Chehalis River near Adna, WA | WA | 340 | 194 | 1,044.4 | 102.4 | 14-day |
| Chehalis River at Wwtp at Chehalis, WA | WA | 618 | 161 | — | — | — |
| Chehalis River near Grand Mound, WA | WA | 895 | 132 | 2,347 | 350.7 | 14-day |
| Chehalis River near Rochester, WA | WA | 957 | 117 | — | — | — |
| Chehalis River at Porter, WA | WA | 1,294 | 38 | 3,683.7 | 566.6 | 14-day |
| Chehalis River near Montesano, WA | WA | 1,780 | 10 | — | — | — |
Common questions
- How many gauges are on the Chehalis River?
- Rivermatics tracks 7 USGS streamgages on the Chehalis River, across Washington. 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 Chehalis River?
- Yes, at 4 of the 7 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.
- Can I use Chehalis 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.