Reservoir · Idaho · United States · BOR RISE
Island Park Reservoir and Dam (ISL)
46.4% full
Capacity
157.45 hm³
Volume stored
73 hm³
Coordinates
44.419°N, 111.398°W
Last updated
2026-07-28
Current fill
46.4%vs 7 days ago
-0.7%losing
vs 1 year ago
-48.8%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. 44.419, -111.398 · Open in Google Maps
About Island Park Reservoir and Dam (ISL)
As of July 28, 2026, Island Park Reservoir and Dam (ISL) is filled to 46.4% of its total capacity, holding roughly 73 hm³ of water out of a maximum 157 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 (-0.7 pts), and it is 48.8 points below its level on the same date a year earlier.
Across the readings we hold for Island Park Reservoir and Dam (ISL) — 2190 data points between July 31, 2021 and July 28, 2026 — the level has ranged from a low of 34.4% (September 8, 2025) to a high of 105.0% (May 19, 2022). On average the reservoir is fullest around May and at its lowest around September.
It is operated by BOR primarily for multiple purposes. It lies within the Idaho basin at 44.419°N, 111.398°W.
Key facts
- Current fill level
- 46.4%
- Water stored
- 73 hm³
- Total capacity
- 157 hm³
- 7-day change
- ▼ 0.7 pts
- Year-on-year
- ▼ 48.8 pts
- Primary use
- Multipurpose
- River basin
- Idaho
- Operator
- BOR
- Coordinates
- 44.419°N, 111.398°W
- Last updated
- July 28, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 28 Jul 2026 | 46.4% | 73 |
| 27 Jul 2026 | 47.1% | 74 |
| 26 Jul 2026 | 47.7% | 75 |
| 25 Jul 2026 | 48.3% | 76 |
| 24 Jul 2026 | 49.2% | 78 |
| 23 Jul 2026 | 49.9% | 79 |
| 22 Jul 2026 | 50.8% | 80 |
| 21 Jul 2026 | 51.4% | 81 |
| 20 Jul 2026 | 52.3% | 82 |
| 19 Jul 2026 | 53.6% | 84 |
| 18 Jul 2026 | 54.9% | 86 |
| 17 Jul 2026 | 56.4% | 89 |
Frequently asked questions
What is the current water level of Island Park Reservoir and Dam (ISL)?
As of July 28, 2026, Island Park Reservoir and Dam (ISL) is at 46.4% of its capacity, holding approximately 73 hm³ of water, according to BOR RISE (US Bureau of Reclamation) data.
Is Island Park Reservoir and Dam (ISL) reservoir full?
No. As of July 28, 2026, Island Park Reservoir and Dam (ISL) is within its normal operating range at 46.4% of its capacity, so it is not full.
Is the water level at Island Park Reservoir and Dam (ISL) rising or falling?
The level at Island Park Reservoir and Dam (ISL) has been broadly stable over the latest week on record (-0.7 points).
How much water can Island Park Reservoir and Dam (ISL) hold?
Island Park Reservoir and Dam (ISL) has a total capacity of 157 hm³.
Where is Island Park Reservoir and Dam (ISL) reservoir located?
Island Park Reservoir and Dam (ISL) is located in Idaho, United States, within the Idaho basin (coordinates 44.419°N, 111.398°W).
What is Island Park Reservoir and Dam (ISL) used for?
Island Park Reservoir and Dam (ISL) is used primarily for multiple purposes, and is managed by BOR.