Reservoir · Colorado · United States · BOR RISE
Green Mountain Reservoir
Green Mountain Reservoir Dam and Powerplant
13.4% full
Capacity
189.51 hm³
Volume stored
25 hm³
Coordinates
39.879°N, 106.313°W
Last updated
2026-09-09
Current fill
13.4%vs 7 days ago
-1.2%losing
vs 1 year ago
-48.4%year-over-year
7-day trend
→stable
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: 2026-09-09.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 39.879, -106.313 · Open in Google Maps
About Green Mountain Reservoir
As of September 9, 2026, Green Mountain Reservoir is filled to 13.4% of its total capacity, holding roughly 25 hm³ of water out of a maximum 190 hm³. At this level the reservoir is critically low.
Over the most recent week on record the fill level has held broadly steady (-1.2 pts), and it is 48.4 points below its level on the same date a year earlier.
Across the readings we hold for Green Mountain Reservoir — 1950 data points between September 12, 2021 and September 9, 2026 — the level has ranged from a low of 13.4% (September 9, 2026) to a high of 99.4% (July 21, 2023). On average the reservoir is fullest around July and at its lowest around April.
It is operated by BOR primarily for multiple purposes. It lies within the Colorado basin at 39.879°N, 106.313°W.
Key facts
- Current fill level
- 13.4%
- Water stored
- 25 hm³
- Total capacity
- 190 hm³
- 7-day change
- ▼ 1.2 pts
- Year-on-year
- ▼ 48.4 pts
- Primary use
- Multipurpose
- River basin
- Colorado
- Operator
- BOR
- Coordinates
- 39.879°N, 106.313°W
- Last updated
- September 9, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 9 Sep 2026 | 13.4% | 25 |
| 8 Sep 2026 | 13.5% | 26 |
| 7 Sep 2026 | 13.7% | 26 |
| 6 Sep 2026 | 13.9% | 26 |
| 5 Sep 2026 | 14.0% | 27 |
| 4 Sep 2026 | 14.2% | 27 |
| 3 Sep 2026 | 14.4% | 27 |
| 2 Sep 2026 | 14.6% | 28 |
| 1 Sep 2026 | 14.8% | 28 |
| 31 Aug 2026 | 14.9% | 28 |
| 30 Aug 2026 | 15.0% | 29 |
| 29 Aug 2026 | 15.2% | 29 |