Reservoir · South Dakota · United States · USACE CWMS
Big Bend Dam & Reservoir
97.9% full
Capacity
2,127.76 hm³
Volume stored
2083 hm³
Vs month average
101% of normal
Coordinates
44.041°N, 99.445°W
Last updated
2026-10-27
Current fill
97.9%vs 7 days ago
+0.6 ppgaining
vs 1 year ago
+0.4 ppyear-over-year
7-day trend
→stable
Drought context
Storage vs October average
101%of normal
97.9% full on 2026-10-27, against an average of 97.0% for October across 6 years of readings (+0.9 points).
Drought Monitor at this site · 20 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: 2026-10-27.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 44.041°N, 99.445°W · Open in Google Maps
About Big Bend Dam & Reservoir
As of October 27, 2026, Big Bend Dam & Reservoir is filled to 97.9% of its total capacity, holding 2,083 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 (+0.6 pp), 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 29, 2021 and October 27, 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 is at 44.041°N, 99.445°W.
Key facts
- Current fill level
- 97.9% of total capacity
- Water stored
- 2,083 hm³
- Total capacity
- 2,128 hm³
- 7-day change
- ▲ 0.6 pp
- Year-on-year
- ▲ 0.4 pp
- Primary use
- Multipurpose
- Operator
- USACE
- Coordinates
- 44.041°N, 99.445°W
- Last updated
- October 27, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 27 Oct 2026 | 97.9% | 2,083 |
| 26 Oct 2026 | 98.0% | 2,086 |
| 25 Oct 2026 | 97.0% | 2,065 |
| 24 Oct 2026 | 96.1% | 2,044 |
| 23 Oct 2026 | 96.2% | 2,046 |
| 22 Oct 2026 | 96.5% | 2,053 |
| 21 Oct 2026 | 96.8% | 2,060 |
| 20 Oct 2026 | 97.3% | 2,071 |
| 19 Oct 2026 | 97.7% | 2,080 |
| 18 Oct 2026 | 97.0% | 2,064 |
| 17 Oct 2026 | 96.2% | 2,046 |
| 16 Oct 2026 | 96.8% | 2,060 |