Reservoir · Missouri · United States · USACE CWMS
Mark Twain Pool
25.0% full
Capacity
2,296.74 hm³
Volume stored
574 hm³
Coordinates
39.525°N, 91.644°W
Last updated
2026-09-11
Current fill
25.0%vs 7 days ago
-0.3%losing
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. 39.525, -91.644 · Open in Google Maps
About Mark Twain Pool
As of September 11, 2026, Mark Twain Pool is filled to 25.0% of its total capacity, holding roughly 574 hm³ of water out of a maximum 2,297 hm³. At this level the reservoir is low.
Over the most recent week on record the fill level has held broadly steady (-0.3 pts).
Across the readings we hold for Mark Twain Pool — 198 data points between September 12, 2021 and September 11, 2026 — the level has ranged from a low of 24.9% (September 9, 2026) to a high of 40.6% (June 15, 2026). On average the reservoir is fullest around June and at its lowest around August.
It is operated by USACE primarily for multiple purposes. It lies within the Missouri basin at 39.525°N, 91.644°W.
Key facts
- Current fill level
- 25.0%
- Water stored
- 574 hm³
- Total capacity
- 2,297 hm³
- 7-day change
- ▼ 0.3 pts
- Primary use
- Multipurpose
- River basin
- Missouri
- Operator
- USACE
- Coordinates
- 39.525°N, 91.644°W
- Last updated
- September 11, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 11 Sep 2026 | 25.0% | 574 |
| 10 Sep 2026 | 25.0% | 575 |
| 9 Sep 2026 | 24.9% | 573 |
| 8 Sep 2026 | 25.0% | 575 |
| 7 Sep 2026 | 25.2% | 578 |
| 6 Sep 2026 | 25.2% | 579 |
| 5 Sep 2026 | 25.2% | 580 |
| 4 Sep 2026 | 25.3% | 582 |
| 3 Sep 2026 | 25.4% | 584 |
| 2 Sep 2026 | 25.5% | 585 |
| 1 Sep 2026 | 25.6% | 587 |
| 31 Aug 2026 | 25.7% | 590 |