Reservoir · Idaho · United States · BOR RISE
Mann Lake and Reservoir A Dam (RSA)
37.1% full
Capacity
4.07 hm³
Volume stored
2 hm³
Coordinates
46.371°N, 116.858°W
Last updated
2026-07-28
Current fill
37.1%vs 7 days ago
-1.0%losing
vs 1 year ago
-27.5%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. 46.371, -116.858 · Open in Google Maps
About Mann Lake and Reservoir A Dam (RSA)
As of July 28, 2026, Mann Lake and Reservoir A Dam (RSA) is filled to 37.1% of its total capacity, holding roughly 2 hm³ of water out of a maximum 4 hm³. At this level the reservoir is low.
Over the most recent week on record the fill level has held broadly steady (-1.0 pts), and it is 27.5 points below its level on the same date a year earlier.
Across the readings we hold for Mann Lake and Reservoir A Dam (RSA) — 2188 data points between July 31, 2021 and July 28, 2026 — the level has ranged from a low of 23.6% (September 4, 2021) to a high of 73.7% (June 13, 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 Idaho basin at 46.371°N, 116.858°W.
Key facts
- Current fill level
- 37.1%
- Water stored
- 2 hm³
- Total capacity
- 4 hm³
- 7-day change
- ▼ 1.0 pts
- Year-on-year
- ▼ 27.5 pts
- Primary use
- Multipurpose
- River basin
- Idaho
- Operator
- BOR
- Coordinates
- 46.371°N, 116.858°W
- Last updated
- July 28, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 28 Jul 2026 | 37.1% | 2 |
| 27 Jul 2026 | 38.1% | 2 |
| 26 Jul 2026 | 38.1% | 2 |
| 25 Jul 2026 | 38.6% | 2 |
| 24 Jul 2026 | 39.1% | 2 |
| 22 Jul 2026 | 39.8% | 2 |
| 21 Jul 2026 | 40.5% | 2 |
| 20 Jul 2026 | 40.8% | 2 |
| 19 Jul 2026 | 41.3% | 2 |
| 18 Jul 2026 | 41.8% | 2 |
| 17 Jul 2026 | 42.5% | 2 |
| 16 Jul 2026 | 43.0% | 2 |
Frequently asked questions
What is the current water level of Mann Lake and Reservoir A Dam (RSA)?
As of July 28, 2026, Mann Lake and Reservoir A Dam (RSA) is at 37.1% of its capacity, holding approximately 2 hm³ of water, according to BOR RISE (US Bureau of Reclamation) data.
Is Mann Lake and Reservoir A Dam (RSA) reservoir full?
No. As of July 28, 2026, Mann Lake and Reservoir A Dam (RSA) is low at 37.1% of its capacity, so it is not full.
Is the water level at Mann Lake and Reservoir A Dam (RSA) rising or falling?
The level at Mann Lake and Reservoir A Dam (RSA) has been broadly stable over the latest week on record (-1.0 points).
How much water can Mann Lake and Reservoir A Dam (RSA) hold?
Mann Lake and Reservoir A Dam (RSA) has a total capacity of 4 hm³.
Where is Mann Lake and Reservoir A Dam (RSA) reservoir located?
Mann Lake and Reservoir A Dam (RSA) is located in Idaho, United States, within the Idaho basin (coordinates 46.371°N, 116.858°W).
What is Mann Lake and Reservoir A Dam (RSA) used for?
Mann Lake and Reservoir A Dam (RSA) is used primarily for multiple purposes, and is managed by BOR.