4 USGS Streamgages · Columbia River system
Mill Creek flows and levels
Mill Creek is gauged at 4 USGS streamgages in Washington, each tracked by Rivermatics. The mainstem runs about 35 miles (57 km) from headwaters to outlet. It drains into the Columbia River system. It drains roughly 115 square miles at its outlet. 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 |
|---|---|---|---|---|---|---|
| Mill Creek near Walla Walla, WA | WA | 60 | — | 149.4 | 34.2 | 14-day |
| Mill Creek at Five Mile Rd Br near Walla Walla, WA | WA | 93 | — | 182.7 | 27 | 14-day |
| Mill Creek at Walla Walla, WA | WA | 96 | — | 136.2 | 2.6 | 14-day |
| Mill Creek at Last Chance Rd Br near College Place, WA | WA | — | — | 147.9 | 7.1 | 14-day |
Typical flow by month at Mill Creek at Last Chance Rd Br near College Place, WA
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 5 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 | — | 148.1 | — | |
| February | — | 157 | — | |
| March | — | 210.1 | — | |
| April | — | 147.9 | — | |
| May | — | 89.7 | — | |
| June | — | 22.1 | — | |
| July | — | 7.1 | — | |
| August | — | 12.5 | — | |
| September | — | 19.5 | — | |
| October | — | 23.8 | — | |
| November | — | 61.5 | — | |
| December | — | 125 | — |
All values in cubic feet per second (cfs).
Common questions
- When does the Mill Creek run highest?
- March, on the long-term record at Mill Creek at Last Chance Rd Br near College Place, WA — the furthest-downstream gauge Rivermatics tracks on this river. Median daily flow there is about 210.1 cfs that month, against 7.1 cfs in July, 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 Mill Creek?
- Rivermatics tracks 4 USGS streamgages on the Mill Creek, 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 Mill Creek?
- Yes, at 4 of the 4 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 Mill Creek part of?
- The Mill Creek 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 Mill Creek 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