Streamflow
Below normalGunnison River below Gunnison Tunnel streamflow
Daily mean discharge, Gunnison-Colorado basin, Colorado
Data through Sep 30, 2026 · source last checked Oct 1, 2026 · page revised Oct 1, 2026
Cite
- Discharge
About this data
- Source
- US Geological Survey (USGS)
- Series
- Daily mean streamflow (discharge)
- Geography
- Gunnison River below Gunnison Tunnel
- Unit
- cfs
- Calculation
- Daily mean
- Last observation
- Sep 30, 2026
- Update frequency
- Daily
Now 210 cfs, 53% below the 5-yr median.
The Gunnison River below Gunnison Tunnel ran at 210 cfs, down 41.8% from a year ago. Flow is 53% below the 5-year median. The gauge fell 14.6% week over week.
| Period | Current | Prior | Change |
|---|---|---|---|
| Week over week | 210 cfs | 246 cfs | -14.6% |
| Month over month | 210 cfs | 244 cfs | -13.9% |
| Year over year | 210 cfs | 361 cfs | -41.8% |
| vs 5-yr median | 210 cfs | 449 cfs | -53.2% |
| Reading | Discharge |
|---|---|
| Lowest on record for this week | 328 cfs |
| Median for this week | 449 cfs |
| Highest on record for this week | 709 cfs |
Previous weeks
Week of Sep 23, 2026
Gunnison River discharge sits at 246 cfs, 45% below the 5-year median. The river is down 36.3% year over year and 7.2% on the month.
Week of Sep 15, 2026
Gunnison River below Gunnison Tunnel streamflow fell to 252 cfs, 44% below the 5-year median. Flow dropped 39.4% year over year and 12.2% month over month.
Week of Sep 2, 2026
Discharge stands at 245 cfs, 49% below the 5-year median. The gauge fell 5.8% on the week.
Week of Aug 26, 2026
Streamflow at Gunnison River below Gunnison Tunnel reads 260 cfs, 46% below the 5-year median. The gauge is down 46% from year-ago discharge of 482 cfs.
About Gunnison River below Gunnison Tunnel
USGS gage 09128000 sits on the Gunnison River just below the Gunnison Tunnel diversion, at the foot of the Black Canyon in western Colorado. Above it is Reclamation's Aspinall Unit, the three-reservoir chain of Blue Mesa, Morrow Point and Crystal that stores most of the upper Gunnison's runoff. Directly at this point the Gunnison Tunnel takes water out of the river and carries it under the canyon rim to the Uncompahgre Valley, so the gage reads the river after both the reservoirs and the diversion have had their say.
The year runs on release schedules: a spring peak shaped to meet a National Park Service water right in the Black Canyon, then a summer floor. Because Blue Mesa is the largest reservoir in Colorado and a key piece of Upper Basin drought-response storage, low readings here are usually a symptom of a decision to hold water back rather than of the weather in any given week.