Reservoirs
Below normalBoysen Reservoir water level
Live reservoir storage and water level in Wind-Bighorn-Missouri basin, Wyoming
Data through Oct 15, 2026 · source last checked Oct 17, 2026 · page revised Oct 16, 2026
Cite
- Storage
About this data
- Source
- US Bureau of Reclamation RISE; California reservoirs via CA DWR CDEC
- Series
- End-of-day reservoir storage
- Geography
- Boysen Reservoir water level
- Unit
- acre-feet
- Calculation
- Daily reading
- Last observation
- Oct 15, 2026
- Update frequency
- Daily
Now 504,275 af, 20% below the 5-yr median, 68% of capacity.
Boysen storage stands at 504,275 af, 20% below the 5-year median and 68% of capacity. The reservoir gained 1.7% over the past week and 3.3% over the past month. Year-over-year storage is down 1.2%.
| Period | Current | Prior | Change |
|---|---|---|---|
| Week over week | 504,275 af | 495,747 af | +1.7% |
| Month over month | 504,275 af | 488,150 af | +3.3% |
| Year over year | 504,275 af | 510,214 af | -1.2% |
| vs 5-yr median | 504,275 af | 633,662 af | -20.4% |
| Measure | Value |
|---|---|
| Latest reading, Oct 15, 2026 | 4,710.83 ft above sea level |
| Change from a week earlier | +0.61 ft |
| Change from a year earlier | -0.42 ft |
| 5-yr median for the date | 4,719.16 ft |
| Below full pool | 6.17 ft |
| Five-year low | 4,709.54 ft (Sep 19, 2026) |
| Five-year high | 4,728.41 ft (Jun 24, 2023) |
| Measure | Value | Source |
|---|---|---|
| Full pool elevation | 4,717 ft above sea level (top of active conservation pool) | USBR |
| Maximum depth at the dam | 117 ft | USBR |
| Surface area at full pool | 19,560 acres | USACE NID |
| Total capacity | 741,594 acre-feet | USBR |
Previous weeks
An earlier week
Boysen storage is at 501,326 af, running 21% below the 5-year median. The reservoir gained 1.0% week over week and 2.7% month over month. Year over year, storage is down 1.8%.
Week of Oct 7, 2026
Boysen storage stands at 496,296 af, down 3.1% from a year ago and 21% below the 5-year median. The reservoir is at 67% of capacity.
Week of Sep 23, 2026
Boysen storage stands at 492,554 af, down 5.2% year over year and 23% below the 5-year median. The reservoir gained 1.0% on the week.
Week of Sep 15, 2026
Boysen storage stands at 488,150 af, down 5.3% over the past month and 7.7% year-over-year. The reservoir is at 66% of capacity and 24% below its 5-year median.
About Boysen Reservoir
Boysen Reservoir's water level is 4,710.83 feet above sea level as of Oct 15, 2026, 6.17 feet below full pool (4,717 feet), with 504,275 acre-feet in storage (68% of capacity). That is 0.61 feet higher than a week earlier and 0.42 feet lower than a year earlier.
Boysen Dam holds the Wind River at the upstream mouth of Wind River Canyon, a Pick-Sloan unit above Thermopolis in central Wyoming. Reclamation operates it for irrigation, flood control, power, and sediment retention. Below the canyon the same river changes names, becoming the Bighorn.
Total capacity is 741,594 af, over the past five years storage has ranged from 486,370 af to 810,589 af.
Boysen Reservoir is one of the 21 major reservoirs this site totals each day. For the combined picture, western reservoir levels carries the storage of all 21 on one chart, which is the number to watch when the question is about the West as a whole rather than about this project.
Those figures describe the reservoir at full pool, not today. The chart at the top of this page tracks storage in acre-feet and the elevation table tracks the water surface in feet, so read storage against total capacity for how full the reservoir is, and the elevation against the full pool elevation and maximum depth for the size of the water column behind the dam. The two do not move together one for one: a reservoir narrows as it deepens, so one holding half its capacity still stands more than half as deep.
Sources: full pool elevation and maximum depth from the Bureau of Reclamation; surface area from the Army Corps' National Inventory of Dams; total capacity from the Bureau of Reclamation.