Reservoir · Pennsylvania · United States · USACE CWMS
Allegheny Reservoir
99.6% full
Capacity
706.79 hm³
Volume stored
704 hm³
Coordinates
41.838°N, 79.004°W
Last updated
2026-09-11
Current fill
99.6%vs 7 days ago
+1.3%gaining
vs 1 year ago
N/A7-day trend
→stable
Data source: USACE CWMS — US Army Corps of Engineers — 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: 2026-09-11.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 41.838, -79.004 · Open in Google Maps
About Allegheny Reservoir
As of September 11, 2026, Allegheny Reservoir is filled to 99.6% of its total capacity, holding roughly 704 hm³ of water out of a maximum 707 hm³. At this level the reservoir is high.
Over the most recent week on record the fill level has held broadly steady (+1.3 pts).
Across the readings we hold for Allegheny Reservoir — 327 data points between September 12, 2021 and September 11, 2026 — the level has ranged from a low of 55.5% (February 2, 2022) to a high of 105.0% (September 24, 2021). On average the reservoir is fullest around May and at its lowest around January.
It is operated by USACE primarily for multiple purposes. It lies within the Pennsylvania basin at 41.838°N, 79.004°W.
Key facts
- Current fill level
- 99.6%
- Water stored
- 704 hm³
- Total capacity
- 707 hm³
- 7-day change
- ▲ 1.3 pts
- Primary use
- Multipurpose
- River basin
- Pennsylvania
- Operator
- USACE
- Coordinates
- 41.838°N, 79.004°W
- Last updated
- September 11, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 11 Sep 2026 | 99.6% | 704 |
| 10 Sep 2026 | 99.6% | 704 |
| 9 Sep 2026 | 99.1% | 700 |
| 8 Sep 2026 | 99.1% | 700 |
| 7 Sep 2026 | 98.6% | 697 |
| 6 Sep 2026 | 98.8% | 698 |
| 5 Sep 2026 | 98.8% | 698 |
| 4 Sep 2026 | 98.3% | 694 |
| 3 Sep 2026 | 97.1% | 686 |
| 2 Sep 2026 | 96.2% | 680 |
| 1 Sep 2026 | 96.4% | 681 |
| 31 Aug 2026 | 96.6% | 682 |