Reservoir · Wyoming · United States · BOR RISE
Guernsey Reservoir Dam and Powerplant
43.7% full
Capacity
56.26 hm³
Volume stored
25 hm³
Coordinates
42.289°N, 104.763°W
Last updated
2026-07-28
Current fill
43.7%vs 7 days ago
+9.7%gaining
vs 1 year ago
-0.2%year-over-year
7-day trend
↑rising
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: 2026-07-28.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 42.289, -104.763 · Open in Google Maps
About Guernsey Reservoir Dam and Powerplant
As of July 28, 2026, Guernsey Reservoir Dam and Powerplant is filled to 43.7% of its total capacity, holding roughly 25 hm³ of water out of a maximum 56 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 9.7 percentage points, and it sits close to where it was a year earlier.
Across the readings we hold for Guernsey Reservoir Dam and Powerplant — 1817 data points between July 31, 2021 and July 28, 2026 — the level has ranged from a low of 1.2% (September 9, 2021) to a high of 84.7% (January 13, 2024). On average the reservoir is fullest around June and at its lowest around October.
It is operated by BOR primarily for multiple purposes. It lies within the Wyoming basin at 42.289°N, 104.763°W.
Key facts
- Current fill level
- 43.7%
- Water stored
- 25 hm³
- Total capacity
- 56 hm³
- 7-day change
- ▲ 9.7 pts
- Year-on-year
- ▼ 0.2 pts
- Primary use
- Multipurpose
- River basin
- Wyoming
- Operator
- BOR
- Coordinates
- 42.289°N, 104.763°W
- Last updated
- July 28, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 28 Jul 2026 | 43.7% | 25 |
| 27 Jul 2026 | 34.0% | 19 |
| 26 Jul 2026 | 24.2% | 14 |
| 25 Jul 2026 | 14.4% | 8 |
| 24 Jul 2026 | 3.5% | 2 |
| 23 Jul 2026 | 2.4% | 1 |
| 22 Jul 2026 | 2.2% | 1 |
| 21 Jul 2026 | 1.8% | 1 |
| 20 Jul 2026 | 2.5% | 1 |
| 19 Jul 2026 | 3.2% | 2 |
| 18 Jul 2026 | 3.6% | 2 |
| 17 Jul 2026 | 3.4% | 2 |
Frequently asked questions
What is the current water level of Guernsey Reservoir Dam and Powerplant?
As of July 28, 2026, Guernsey Reservoir Dam and Powerplant is at 43.7% of its capacity, holding approximately 25 hm³ of water, according to BOR RISE (US Bureau of Reclamation) data.
Is Guernsey Reservoir Dam and Powerplant reservoir full?
No. As of July 28, 2026, Guernsey Reservoir Dam and Powerplant is within its normal operating range at 43.7% of its capacity, so it is not full.
Is the water level at Guernsey Reservoir Dam and Powerplant rising or falling?
The level at Guernsey Reservoir Dam and Powerplant is rising — it gained 9.7 percentage points over the latest week on record.
How much water can Guernsey Reservoir Dam and Powerplant hold?
Guernsey Reservoir Dam and Powerplant has a total capacity of 56 hm³.
Where is Guernsey Reservoir Dam and Powerplant reservoir located?
Guernsey Reservoir Dam and Powerplant is located in Wyoming, United States, within the Wyoming basin (coordinates 42.289°N, 104.763°W).
What is Guernsey Reservoir Dam and Powerplant used for?
Guernsey Reservoir Dam and Powerplant is used primarily for multiple purposes, and is managed by BOR.