Reservoir · Idaho · United States · BOR RISE
Arrowrock Reservoir and Dam (ARK)
78.7% full
Capacity
335.78 hm³
Volume stored
264 hm³
Coordinates
43.595°N, 115.923°W
Last updated
2026-06-11
Current fill
78.7%vs 7 days ago
-1.5%losing
vs 1 year ago
-19.4%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: 2026-06-11.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 43.595, -115.923 · Open in Google Maps
About Arrowrock Reservoir and Dam (ARK)
As of June 11, 2026, Arrowrock Reservoir and Dam (ARK) is filled to 78.7% of its total capacity, holding roughly 264 hm³ of water out of a maximum 336 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 (-1.5 pts), and it is 19.4 points below its level on the same date a year earlier.
Across the readings we hold for Arrowrock Reservoir and Dam (ARK) — 2192 data points between June 13, 2021 and June 11, 2026 — the level has ranged from a low of 13.4% (July 25, 2021) to a high of 98.9% (April 17, 2026). On average the reservoir is fullest around June and at its lowest around October.
It is operated by BOR primarily for multiple purposes. It lies within the Idaho basin at 43.595°N, 115.923°W.
Key facts
- Current fill level
- 78.7%
- Water stored
- 264 hm³
- Total capacity
- 336 hm³
- 7-day change
- ▼ 1.5 pts
- Year-on-year
- ▼ 19.4 pts
- Primary use
- Multipurpose
- River basin
- Idaho
- Operator
- BOR
- Coordinates
- 43.595°N, 115.923°W
- Last updated
- June 11, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 11 Jun 2026 | 78.7% | 264 |
| 10 Jun 2026 | 80.2% | 269 |
| 9 Jun 2026 | 81.5% | 274 |
| 8 Jun 2026 | 82.8% | 278 |
| 7 Jun 2026 | 84.0% | 282 |
| 6 Jun 2026 | 85.1% | 286 |
| 5 Jun 2026 | 86.1% | 289 |
| 4 Jun 2026 | 87.0% | 292 |
| 3 Jun 2026 | 87.9% | 295 |
| 2 Jun 2026 | 88.8% | 298 |
| 1 Jun 2026 | 89.4% | 300 |
| 31 May 2026 | 90.0% | 302 |
Frequently asked questions
What is the current water level of Arrowrock Reservoir and Dam (ARK)?
As of June 11, 2026, Arrowrock Reservoir and Dam (ARK) is at 78.7% of its capacity, holding approximately 264 hm³ of water, according to BOR RISE (US Bureau of Reclamation) data.
Is Arrowrock Reservoir and Dam (ARK) reservoir full?
No. As of June 11, 2026, Arrowrock Reservoir and Dam (ARK) is within its normal operating range at 78.7% of its capacity, so it is not full.
Is the water level at Arrowrock Reservoir and Dam (ARK) rising or falling?
The level at Arrowrock Reservoir and Dam (ARK) has been broadly stable over the latest week on record (-1.5 points).
How much water can Arrowrock Reservoir and Dam (ARK) hold?
Arrowrock Reservoir and Dam (ARK) has a total capacity of 336 hm³.
Where is Arrowrock Reservoir and Dam (ARK) reservoir located?
Arrowrock Reservoir and Dam (ARK) is located in Idaho, United States, within the Idaho basin (coordinates 43.595°N, 115.923°W).
What is Arrowrock Reservoir and Dam (ARK) used for?
Arrowrock Reservoir and Dam (ARK) is used primarily for multiple purposes, and is managed by BOR.