Reservoir · Montana · United States · BOR RISE
Willow Creek Reservoir
Willow Creek Reservoir and Dam (MT)
32.8% full
Capacity
39.84 hm³
Volume stored
13 hm³
Coordinates
47.547°N, 112.429°W
Last updated
2026-09-09
Current fill
32.8%vs 7 days ago
+2.5%gaining
vs 1 year ago
+19.9%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: 2026-09-09.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 47.547, -112.429 · Open in Google Maps
About Willow Creek Reservoir
As of September 9, 2026, Willow Creek Reservoir is filled to 32.8% of its total capacity, holding roughly 13 hm³ of water out of a maximum 40 hm³. At this level the reservoir is low.
Over the most recent week on record the fill level has risen by 2.5 percentage points, and it is 19.9 points above its level on the same date a year earlier.
Across the readings we hold for Willow Creek Reservoir — 2037 data points between September 12, 2021 and September 9, 2026 — the level has ranged from a low of 12.5% (November 21, 2025) to a high of 93.8% (May 29, 2022). On average the reservoir is fullest around June and at its lowest around September.
It is operated by BOR primarily for multiple purposes. It lies within the Montana basin at 47.547°N, 112.429°W.
Key facts
- Current fill level
- 32.8%
- Water stored
- 13 hm³
- Total capacity
- 40 hm³
- 7-day change
- ▲ 2.5 pts
- Year-on-year
- ▲ 19.9 pts
- Primary use
- Multipurpose
- River basin
- Montana
- Operator
- BOR
- Coordinates
- 47.547°N, 112.429°W
- Last updated
- September 9, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 9 Sep 2026 | 32.8% | 13 |
| 8 Sep 2026 | 32.5% | 13 |
| 7 Sep 2026 | 32.1% | 13 |
| 6 Sep 2026 | 31.5% | 13 |
| 5 Sep 2026 | 31.0% | 12 |
| 4 Sep 2026 | 30.6% | 12 |
| 3 Sep 2026 | 30.6% | 12 |
| 2 Sep 2026 | 30.3% | 12 |
| 1 Sep 2026 | 30.3% | 12 |
| 31 Aug 2026 | 30.3% | 12 |
| 30 Aug 2026 | 30.4% | 12 |
| 29 Aug 2026 | 30.5% | 12 |