Reservoir · Montana · United States · BOR RISE
Nelson Reservoir and Nelson Dikes
76.4% full
Capacity
97.72 hm³
Volume stored
75 hm³
Coordinates
48.530°N, 107.519°W
Last updated
2026-07-28
Current fill
76.4%vs 7 days ago
-0.5%losing
vs 1 year ago
+22.4%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: 2026-07-28.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 48.530, -107.519 · Open in Google Maps
About Nelson Reservoir and Nelson Dikes
As of July 28, 2026, Nelson Reservoir and Nelson Dikes is filled to 76.4% of its total capacity, holding roughly 75 hm³ of water out of a maximum 98 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 22.4 points above its level on the same date a year earlier.
Across the readings we hold for Nelson Reservoir and Nelson Dikes — 1829 data points between July 31, 2021 and July 28, 2026 — the level has ranged from a low of 40.8% (July 31, 2021) to a high of 99.0% (May 6, 2024). On average the reservoir is fullest around May and at its lowest around February.
It is operated by BOR primarily for multiple purposes. It lies within the Montana basin at 48.530°N, 107.519°W.
Key facts
- Current fill level
- 76.4%
- Water stored
- 75 hm³
- Total capacity
- 98 hm³
- 7-day change
- ▼ 0.5 pts
- Year-on-year
- ▲ 22.4 pts
- Primary use
- Multipurpose
- River basin
- Montana
- Operator
- BOR
- Coordinates
- 48.530°N, 107.519°W
- Last updated
- July 28, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 28 Jul 2026 | 76.4% | 75 |
| 27 Jul 2026 | 76.9% | 75 |
| 26 Jul 2026 | 77.2% | 75 |
| 25 Jul 2026 | 77.3% | 76 |
| 24 Jul 2026 | 77.2% | 75 |
| 23 Jul 2026 | 77.2% | 75 |
| 22 Jul 2026 | 76.9% | 75 |
| 21 Jul 2026 | 76.7% | 75 |
| 20 Jul 2026 | 76.3% | 75 |
| 19 Jul 2026 | 75.8% | 74 |
| 18 Jul 2026 | 75.3% | 74 |
| 17 Jul 2026 | 74.9% | 73 |
Frequently asked questions
What is the current water level of Nelson Reservoir and Nelson Dikes?
As of July 28, 2026, Nelson Reservoir and Nelson Dikes is at 76.4% of its capacity, holding approximately 75 hm³ of water, according to BOR RISE (US Bureau of Reclamation) data.
Is Nelson Reservoir and Nelson Dikes reservoir full?
No. As of July 28, 2026, Nelson Reservoir and Nelson Dikes is within its normal operating range at 76.4% of its capacity, so it is not full.
Is the water level at Nelson Reservoir and Nelson Dikes rising or falling?
The level at Nelson Reservoir and Nelson Dikes has been broadly stable over the latest week on record (-0.5 points).
How much water can Nelson Reservoir and Nelson Dikes hold?
Nelson Reservoir and Nelson Dikes has a total capacity of 98 hm³.
Where is Nelson Reservoir and Nelson Dikes reservoir located?
Nelson Reservoir and Nelson Dikes is located in Montana, United States, within the Montana basin (coordinates 48.530°N, 107.519°W).
What is Nelson Reservoir and Nelson Dikes used for?
Nelson Reservoir and Nelson Dikes is used primarily for multiple purposes, and is managed by BOR.