Reservoir · North Dakota · United States · USACE CWMS
Garrison Dam & Reservoir
76.4% full
Capacity
22,819.42 hm³
Volume stored
17441 hm³
Coordinates
47.505°N, 101.432°W
Last updated
2026-09-10
Current fill
76.4%vs 7 days ago
-0.5%losing
vs 1 year ago
-10.9%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. 47.505, -101.432 · Open in Google Maps
About Garrison Dam & Reservoir
As of September 10, 2026, Garrison Dam & Reservoir is filled to 76.4% of its total capacity, holding roughly 17,441 hm³ of water out of a maximum 22,819 hm³. At this level the reservoir is within its normal operating range.
Over the most recent week on record the fill level has held broadly steady (-0.5 pts), and it is 10.9 points below its level on the same date a year earlier.
Across the readings we hold for Garrison Dam & Reservoir — 1821 data points between September 12, 2021 and September 10, 2026 — the level has ranged from a low of 76.2% (March 28, 2023) to a high of 105.0% (July 24, 2023). On average the reservoir is fullest around July and at its lowest around March.
It is operated by USACE primarily for multiple purposes. It lies within the North Dakota basin at 47.505°N, 101.432°W.
Key facts
- Current fill level
- 76.4%
- Water stored
- 17,441 hm³
- Total capacity
- 22,819 hm³
- 7-day change
- ▼ 0.5 pts
- Year-on-year
- ▼ 10.9 pts
- Primary use
- Multipurpose
- River basin
- North Dakota
- Operator
- USACE
- Coordinates
- 47.505°N, 101.432°W
- Last updated
- September 10, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 10 Sep 2026 | 76.4% | 17,441 |
| 9 Sep 2026 | 76.4% | 17,443 |
| 8 Sep 2026 | 76.5% | 17,457 |
| 7 Sep 2026 | 76.6% | 17,476 |
| 6 Sep 2026 | 76.7% | 17,494 |
| 5 Sep 2026 | 76.8% | 17,514 |
| 4 Sep 2026 | 76.8% | 17,534 |
| 3 Sep 2026 | 76.9% | 17,554 |
| 2 Sep 2026 | 77.0% | 17,582 |
| 1 Sep 2026 | 77.2% | 17,605 |
| 31 Aug 2026 | 77.2% | 17,628 |
| 30 Aug 2026 | 77.3% | 17,650 |