Reservoir · Wyoming · United States · BOR RISE
Big Sandy Reservoir
Big Sandy Reservoir and Dam
21.7% full
Capacity
48.97 hm³
Volume stored
11 hm³
Vs month average
52% of normal
Coordinates
42.268°N, 109.432°W
Last updated
2026-10-26
Current fill
21.7%vs 7 days ago
+2.6 ppgaining
vs 1 year ago
-13.6 ppyear-over-year
7-day trend
↑rising
Drought context
Storage vs October average
52%of normal
21.7% full on 2026-10-26, against an average of 41.9% for October across 6 years of readings (-20.2 points).
Drought Monitor at this site · 20 October 2026
D2severe drought
The ground at Big Sandy Reservoir's coordinates falls inside the D2 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: 2026-10-26.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 42.268°N, 109.432°W · Open in Google Maps
About Big Sandy Reservoir
As of October 26, 2026, Big Sandy Reservoir is filled to 21.7% of its total capacity, holding 10.63 hm³ of water out of a maximum 48.97 hm³. At this level the reservoir is low.
Over the most recent week on record the fill level has risen by 2.6 percentage points, and it is 13.6 points below its level on the same date a year earlier.
Across the readings we hold for Big Sandy Reservoir — 1639 data points between October 29, 2021 and October 26, 2026 — the level has ranged from a low of 5.3% (September 16, 2022) to a high of 104.9% (March 31, 2024). On average the reservoir is fullest around June and at its lowest around September.
It is operated by BOR primarily for multiple purposes. It is at 42.268°N, 109.432°W.
Key facts
- Current fill level
- 21.7% of total capacity
- Water stored
- 10.63 hm³
- Total capacity
- 48.97 hm³
- 7-day change
- ▲ 2.6 pp
- Year-on-year
- ▼ 13.6 pp
- Primary use
- Multipurpose
- Operator
- BOR
- Coordinates
- 42.268°N, 109.432°W
- Last updated
- October 26, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 26 Oct 2026 | 21.7% | 10.63 |
| 25 Oct 2026 | 21.2% | 10.4 |
| 24 Oct 2026 | 20.9% | 10.22 |
| 23 Oct 2026 | 20.5% | 10.06 |
| 22 Oct 2026 | 20.2% | 9.9 |
| 21 Oct 2026 | 19.9% | 9.73 |
| 20 Oct 2026 | 19.5% | 9.56 |
| 19 Oct 2026 | 19.1% | 9.37 |
| 18 Oct 2026 | 18.7% | 9.16 |
| 17 Oct 2026 | 18.2% | 8.91 |
| 16 Oct 2026 | 17.6% | 8.64 |
| 15 Oct 2026 | 17.0% | 8.31 |