Reservoir · South Dakota · United States · USACE CWMS
Big Bend Dam & Reservoir
97.7% full
Capacity
2,127.76 hm³
Volume stored
2078 hm³
Vs month average
101% of normal
Coordinates
44.041°N, 99.445°W
Last updated
2026-10-12
Current fill
97.7%vs 7 days ago
0.0%stable
vs 1 year ago
+0.5%year-over-year
7-day trend
→stable
Drought context
Storage vs October average
101%of normal
97.7% full on 2026-10-12, against an average of 97.0% for October across 6 years of readings (+0.7 points).
Drought Monitor at this site · 6 October 2026
Nonenot in a drought category
Big Bend Dam & Reservoir's coordinates fall outside every category on the weekly U.S. Drought Monitor map. That describes local conditions — rainfall, soil moisture, streamflow — not the reservoir's storage. South Dakota drought figures →
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: 2026-10-12.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 44.041, -99.445 · Open in Google Maps
About Big Bend Dam & Reservoir
As of October 12, 2026, Big Bend Dam & Reservoir is filled to 97.7% of its total capacity, holding roughly 2,078 hm³ of water out of a maximum 2,128 hm³. At this level the reservoir is high.
Over the most recent week on record the fill level has held broadly steady (+0.0 pts), and it sits close to where it was a year earlier.
Across the readings we hold for Big Bend Dam & Reservoir — 1821 data points between October 14, 2021 and October 12, 2026 — the level has ranged from a low of 94.9% (July 2, 2022) to a high of 99.2% (April 29, 2024). On average the reservoir is fullest around June and at its lowest around July.
It is operated by USACE primarily for multiple purposes. It lies within the South Dakota basin at 44.041°N, 99.445°W.
Key facts
- Current fill level
- 97.7%
- Water stored
- 2,078 hm³
- Total capacity
- 2,128 hm³
- 7-day change
- No change
- Year-on-year
- ▲ 0.5 pts
- Primary use
- Multipurpose
- River basin
- South Dakota
- Operator
- USACE
- Coordinates
- 44.041°N, 99.445°W
- Last updated
- October 12, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 12 Oct 2026 | 97.7% | 2,078 |
| 11 Oct 2026 | 97.0% | 2,065 |
| 10 Oct 2026 | 96.1% | 2,044 |
| 9 Oct 2026 | 96.3% | 2,049 |
| 8 Oct 2026 | 96.6% | 2,055 |
| 7 Oct 2026 | 96.9% | 2,061 |
| 6 Oct 2026 | 97.3% | 2,070 |
| 5 Oct 2026 | 97.7% | 2,078 |
| 4 Oct 2026 | 97.4% | 2,072 |
| 3 Oct 2026 | 97.4% | 2,073 |
| 2 Oct 2026 | 97.9% | 2,082 |
| 1 Oct 2026 | 98.0% | 2,085 |