2 USGS Streamgages
Williamson River flows and levels
Williamson River is gauged at 2 USGS streamgages in Oregon, each tracked by Rivermatics. It feeds the Klamath River. Drainage area at the gauges ranges from 1,290 square miles at Williamson River near Klamath Agency, OR up to 3,030 at Williamson River below Sprague River near Chiloquin, OR. The gauged reach falls about 339 feet, from 4,487 feet down to 4,149. Rivermatics issues a daily machine-learned 14-day flow outlook for every one 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 |
|---|---|---|---|---|---|---|
| Williamson River near Klamath Agency, OR | OR | 1,290 | 4,487 | 280.9 | 1.9 | 14-day |
| Williamson River below Sprague River near Chiloquin, OR | OR | 3,030 | 4,149 | 1,598 | 543.5 | 14-day + temp |
Typical flow by month at Williamson River below Sprague River near Chiloquin, OR
The furthest-downstream gauge on this river, so the fullest flow it carries here. Long-term daily discharge percentiles from the USGS record (up to 108 years of data), averaged within each month. These describe the historical normal range — they are not a forecast and not today's reading.
| Month | Low p10 | Typical p50 | High p90 | Range |
|---|---|---|---|---|
| January | 577.3 | 782.5 | 1,511 | |
| February | 599.7 | 943.7 | 2,017.2 | |
| March | 724.6 | 1,281.9 | 2,684.5 | |
| April | 781.2 | 1,598 | 3,269.3 | |
| May | 624 | 1,381.3 | 2,903.5 | |
| June | 500.4 | 810 | 1,693.7 | |
| July | 428 | 543.5 | 813.6 | |
| August | 407.5 | 505.4 | 633.3 | |
| September | 444.6 | 530 | 665.9 | |
| October | 518.5 | 593.8 | 789.2 | |
| November | 555.4 | 655.5 | 983.6 | |
| December | 565.9 | 737 | 1,333.5 |
All values in cubic feet per second (cfs).
Common questions
- When does the Williamson River run highest?
- April, on the long-term record at Williamson River below Sprague River near Chiloquin, OR — the furthest-downstream gauge Rivermatics tracks on this river. Median daily flow there is about 1,598 cfs that month, against 505.4 cfs in August, the lowest. Upstream gauges peak on their own schedule; the table on this page gives April and July for each.
- How many gauges are on the Williamson River?
- Rivermatics tracks 2 USGS streamgages on the Williamson 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 Williamson River?
- Yes, at 2 of the 2 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 Williamson 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.