Reservoir · North Dakota · United States · BOR RISE
Edward Arthur Patterson Lake
68.6% full
Capacity
10.62 hm³
Volume stored
7 hm³
Coordinates
46.870°N, 102.827°W
Last updated
2026-09-09
Current fill
68.6%vs 7 days ago
-1.3%losing
vs 1 year ago
-4.3%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. 46.870, -102.827 · Open in Google Maps
About Edward Arthur Patterson Lake
As of September 9, 2026, Edward Arthur Patterson Lake is filled to 68.6% of its total capacity, holding roughly 7 hm³ of water out of a maximum 11 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 (-1.3 pts), and it is 4.3 points below its level on the same date a year earlier.
Across the readings we hold for Edward Arthur Patterson Lake — 1950 data points between September 12, 2021 and September 9, 2026 — the level has ranged from a low of 46.2% (October 8, 2021) to a high of 105.0% (April 30, 2022). On average the reservoir is fullest around May and at its lowest around January.
It is operated by BOR primarily for multiple purposes. It lies within the North Dakota basin at 46.870°N, 102.827°W.
Key facts
- Current fill level
- 68.6%
- Water stored
- 7 hm³
- Total capacity
- 11 hm³
- 7-day change
- ▼ 1.3 pts
- Year-on-year
- ▼ 4.3 pts
- Primary use
- Multipurpose
- River basin
- North Dakota
- Operator
- BOR
- Coordinates
- 46.870°N, 102.827°W
- Last updated
- September 9, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 9 Sep 2026 | 68.6% | 7 |
| 8 Sep 2026 | 69.0% | 7 |
| 7 Sep 2026 | 69.2% | 7 |
| 6 Sep 2026 | 69.3% | 7 |
| 5 Sep 2026 | 69.7% | 7 |
| 4 Sep 2026 | 69.7% | 7 |
| 3 Sep 2026 | 70.0% | 7 |
| 2 Sep 2026 | 69.9% | 7 |
| 1 Sep 2026 | 70.2% | 7 |
| 31 Aug 2026 | 70.3% | 7 |
| 30 Aug 2026 | 70.8% | 8 |
| 29 Aug 2026 | 70.9% | 8 |