Reservoir · Montana · United States · USACE CWMS
Clark Canyon Dam & Reservoir
28.5% full
Capacity
219.64 hm³
Volume stored
63 hm³
Coordinates
45.001°N, 112.859°W
Last updated
2026-09-10
Current fill
28.5%vs 7 days ago
+0.5%gaining
vs 1 year ago
-4.2%year-over-year
7-day trend
→stable
Data source: USACE CWMS — US Army Corps of Engineers — 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: 2026-09-10.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 45.001, -112.859 · Open in Google Maps
About Clark Canyon Dam & Reservoir
As of September 10, 2026, Clark Canyon Dam & Reservoir is filled to 28.5% of its total capacity, holding roughly 63 hm³ of water out of a maximum 220 hm³. At this level the reservoir is low.
Over the most recent week on record the fill level has held broadly steady (+0.5 pts), and it is 4.2 points below its level on the same date a year earlier.
Across the readings we hold for Clark Canyon Dam & Reservoir — 1821 data points between September 12, 2021 and September 10, 2026 — the level has ranged from a low of 25.9% (September 6, 2022) to a high of 98.7% (April 11, 2024). On average the reservoir is fullest around May and at its lowest around September.
It is operated by USACE primarily for multiple purposes. It lies within the Montana basin at 45.001°N, 112.859°W.
Key facts
- Current fill level
- 28.5%
- Water stored
- 63 hm³
- Total capacity
- 220 hm³
- 7-day change
- ▲ 0.5 pts
- Year-on-year
- ▼ 4.2 pts
- Primary use
- Multipurpose
- River basin
- Montana
- Operator
- USACE
- Coordinates
- 45.001°N, 112.859°W
- Last updated
- September 10, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 10 Sep 2026 | 28.5% | 63 |
| 9 Sep 2026 | 28.5% | 63 |
| 8 Sep 2026 | 28.4% | 62 |
| 7 Sep 2026 | 28.3% | 62 |
| 6 Sep 2026 | 28.2% | 62 |
| 5 Sep 2026 | 28.2% | 62 |
| 4 Sep 2026 | 28.1% | 62 |
| 3 Sep 2026 | 28.0% | 62 |
| 2 Sep 2026 | 28.1% | 62 |
| 1 Sep 2026 | 28.1% | 62 |
| 31 Aug 2026 | 28.2% | 62 |
| 30 Aug 2026 | 28.4% | 62 |