Reservoir · Wyoming · United States · BOR RISE
Boysen Reservoir
Boysen Reservoir Dam and Powerplant
74.8% full
Capacity
865.3 hm³
Volume stored
647 hm³
Vs month average
90% of normal
Coordinates
43.400°N, 108.177°W
Last updated
2026-10-28
Current fill
74.8%vs 7 days ago
+1.3 ppgaining
vs 1 year ago
+1.8 ppyear-over-year
7-day trend
↑rising
Drought context
Storage vs October average
90%of normal
74.8% full on 2026-10-28, against an average of 82.9% for October across 6 years of readings (-8.1 points).
Drought Monitor at this site · 27 October 2026
D3extreme drought
The ground at Boysen Reservoir's coordinates falls inside the D3 area of the weekly U.S. Drought Monitor map. That describes local conditions — rainfall, soil moisture, streamflow — not the reservoir's storage. Wyoming drought figures →
Data source: BOR RISE — US Bureau of Reclamation — daily reservoir storage volume. Capacity is the design (normal full-pool) capacity from the US National Inventory of Dams (NID); fill % = current volume ÷ design capacity. Last reading: 2026-10-28.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 43.400°N, 108.177°W · Open in Google Maps
About Boysen Reservoir
As of October 28, 2026, Boysen Reservoir is filled to 74.8% of its total capacity, holding 647.42 hm³ of water out of a maximum 865.3 hm³. At this level the reservoir is within its normal operating range.
Over the most recent week on record the fill level has risen by 1.3 percentage points, and it is 1.8 points above its level on the same date a year earlier.
Across the readings we hold for Boysen Reservoir — 1928 data points between October 30, 2021 and October 28, 2026 — the level has ranged from a low of 69.3% (September 19, 2026) to a high of 104.8% (July 16, 2023). On average the reservoir is fullest around July and at its lowest around May.
It is operated by BOR primarily for multiple purposes. It is at 43.400°N, 108.177°W.
Key facts
- Current fill level
- 74.8% of total capacity
- Water stored
- 647.42 hm³
- Total capacity
- 865.3 hm³
- 7-day change
- ▲ 1.3 pp
- Year-on-year
- ▲ 1.8 pp
- Primary use
- Multipurpose
- Operator
- BOR
- Coordinates
- 43.400°N, 108.177°W
- Last updated
- October 28, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 28 Oct 2026 | 74.8% | 647.42 |
| 27 Oct 2026 | 74.7% | 645.98 |
| 26 Oct 2026 | 74.4% | 644.19 |
| 25 Oct 2026 | 74.2% | 642.41 |
| 24 Oct 2026 | 74.1% | 640.99 |
| 23 Oct 2026 | 73.9% | 639.22 |
| 22 Oct 2026 | 73.7% | 637.97 |
| 21 Oct 2026 | 73.5% | 636.03 |
| 20 Oct 2026 | 73.3% | 634.09 |
| 19 Oct 2026 | 73.0% | 631.97 |
| 18 Oct 2026 | 72.8% | 629.69 |
| 17 Oct 2026 | 72.5% | 627.59 |