Streamflow
Below normalGunnison River below Gunnison Tunnel streamflow
Daily mean discharge, Gunnison-Colorado basin, Colorado
Data through Sep 9, 2026 · source last checked Sep 10, 2026 · page revised Sep 10, 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 9, 2026
- Update frequency
- Daily
Now 245 cfs, 46% below the 5-yr median.
| Period | Current | Prior | Change |
|---|---|---|---|
| Week over week | 245 cfs | 245 cfs | 0.0% |
| Month over month | 245 cfs | 298 cfs | -17.8% |
| Year over year | 245 cfs | 456 cfs | -46.3% |
| vs 5-yr median | 245 cfs | 456 cfs | -46.3% |
| Reading | Discharge |
|---|---|
| Lowest on record for this week | 337 cfs |
| Median for this week | 456 cfs |
| Highest on record for this week | 712 cfs |
Previous weeks
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.
Week of Aug 19, 2026
The Gunnison River below Gunnison Tunnel read 271 cfs, down 5.6% on the week and 56% below the 5-year median. Year-over-year discharge fell 55.7%, though month-over-month flow rose 4.6%.
An earlier week
Gunnison River below Gunnison Tunnel flowed at 287 cfs on August 12, running 56% below the 5-year median. Discharge fell 36.4% month-over-month from 451 cfs. Flow dropped 7.4% on the week.
Week of Aug 13, 2026
Gunnison River below Gunnison Tunnel is running 309 cfs, 50% below the 5-year median. The gauge gained 27.7% from the prior week but is down 49.6% from a year ago.
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.