Reservoir · Idaho · United States · BOR RISE
Lake Walcott
Lake Walcott, Minidoka Dam, and Minidoka Powerplant
8.7% full
Capacity
259.28 hm³
Volume stored
23 hm³
Coordinates
42.670°N, 113.483°W
Last updated
2026-09-30
Current fill
8.7%vs 7 days ago
-19.9%losing
vs 1 year ago
-25.9%year-over-year
7-day trend
↓falling
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: 2026-09-30.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 42.670, -113.483 · Open in Google Maps
About Lake Walcott
As of September 30, 2026, Lake Walcott is filled to 8.7% of its total capacity, holding roughly 23 hm³ of water out of a maximum 259 hm³. At this level the reservoir is critically low.
Over the most recent week on record the fill level has fallen by 19.9 percentage points, and it is 25.9 points below its level on the same date a year earlier.
Across the readings we hold for Lake Walcott — 2186 data points between October 2, 2021 and September 30, 2026 — the level has ranged from a low of 8.7% (September 30, 2026) to a high of 46.1% (May 27, 2024). On average the reservoir is fullest around May and at its lowest around October.
It is operated by BOR primarily for multiple purposes. It lies within the Idaho basin at 42.670°N, 113.483°W.
Key facts
- Current fill level
- 8.7%
- Water stored
- 23 hm³
- Total capacity
- 259 hm³
- 7-day change
- ▼ 19.9 pts
- Year-on-year
- ▼ 25.9 pts
- Primary use
- Multipurpose
- River basin
- Idaho
- Operator
- BOR
- Coordinates
- 42.670°N, 113.483°W
- Last updated
- September 30, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 30 Sep 2026 | 8.7% | 23 |
| 29 Sep 2026 | 10.9% | 28 |
| 28 Sep 2026 | 13.6% | 35 |
| 27 Sep 2026 | 16.2% | 42 |
| 26 Sep 2026 | 20.0% | 52 |
| 25 Sep 2026 | 22.3% | 58 |
| 24 Sep 2026 | 25.9% | 67 |
| 23 Sep 2026 | 28.6% | 74 |
| 22 Sep 2026 | 30.1% | 78 |
| 21 Sep 2026 | 31.5% | 82 |
| 20 Sep 2026 | 32.0% | 83 |
| 19 Sep 2026 | 32.2% | 84 |