Streamflow
Below normalBoise River at Glenwood Bridge streamflow
Daily mean discharge, Boise-Snake basin, Idaho
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
- Boise River at Glenwood Bridge
- Unit
- cfs
- Calculation
- Daily mean
- Last observation
- Sep 30, 2026
- Update frequency
- Daily
Now 389 cfs, 23% below the 5-yr median.
Streamflow on the Boise River at Glenwood Bridge fell to 389 cfs, down 28% on the week. The gauge sits 23% below the 5-yr median. Flow has declined 47% over the past month.
| Period | Current | Prior | Change |
|---|---|---|---|
| Week over week | 389 cfs | 540 cfs | -28.0% |
| Month over month | 389 cfs | 739 cfs | -47.4% |
| Year over year | 389 cfs | 592 cfs | -34.3% |
| vs 5-yr median | 389 cfs | 503 cfs | -22.7% |
| Reading | Discharge |
|---|---|
| Lowest on record for this week | 199 cfs |
| Median for this week | 503 cfs |
| Highest on record for this week | 592 cfs |
Previous weeks
Week of Sep 23, 2026
Boise River at Glenwood Bridge ran 589 cfs, down 5.9% on the week. Over the month, flow declined 24.6%. The gauge read 18% above its 5-year median.
Week of Sep 15, 2026
Boise River streamflow at Glenwood Bridge stood at 635 cfs, 19% above the 5-year median. Discharge declined 6.9% over the past month. The flow is up 7.3% compared to a year ago.
Week of Sep 2, 2026
Boise River at Glenwood Bridge reads 708 cfs, down 7.1% on the week but up 8.4% month over month and year over year. The gauge sits 11% above its 5-year median.
Week of Aug 26, 2026
The Boise River at Glenwood Bridge is running at 762 cfs, 15% above the 5-year median. Flow added 14.4% from a month ago and rose 2.1% over the week. The gauge is down 1.8% from the same date a year ago.
About Boise River at Glenwood Bridge
USGS gage 13206000 sits on the Boise River at Glenwood Bridge, on the western edge of Boise, below the three federal reservoirs that control the basin: Anderson Ranch, Arrowrock and Lucky Peak. Nearly all of the roughly 2,700 square miles above it drains the Boise Mountains, and nearly all of the runoff is captured before it reaches the city.
The result is a year set by operations, not by hydrology. Flow is held low through the winter to keep flood space in the reservoirs, raised sharply in spring when that space has to be recovered, held at a high irrigation-season level through the summer, and cut back in the fall when deliveries end. That fall cut is often the largest single change in the record and it is a schedule, not a drought. The readings that carry real information are the flood-control releases in spring, which are constrained by channel capacity through Boise itself.