Reservoir · South Dakota · United States · USACE CWMS
Angostura Reservoir
58.2% full
Capacity
106.28 hm³
Volume stored
62 hm³
Coordinates
43.307°N, 103.531°W
Last updated
2026-09-10
Current fill
58.2%vs 7 days ago
0.0%stable
vs 1 year ago
-16.1%year-over-year
7-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: 2026-09-10.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 43.307, -103.531 · Open in Google Maps
About Angostura Reservoir
As of September 10, 2026, Angostura Reservoir is filled to 58.2% of its total capacity, holding roughly 62 hm³ of water out of a maximum 106 hm³. At this level the reservoir is within its normal operating range.
Over the most recent week on record the fill level has held broadly steady (+0.0 pts), and it is 16.1 points below its level on the same date a year earlier.
Across the readings we hold for Angostura Reservoir — 1821 data points between September 12, 2021 and September 10, 2026 — the level has ranged from a low of 57.7% (September 5, 2026) to a high of 105.0% (March 25, 2022). On average the reservoir is fullest around June and at its lowest around September.
It is operated by USACE primarily for multiple purposes. It lies within the South Dakota basin at 43.307°N, 103.531°W.
Key facts
- Current fill level
- 58.2%
- Water stored
- 62 hm³
- Total capacity
- 106 hm³
- 7-day change
- No change
- Year-on-year
- ▼ 16.1 pts
- Primary use
- Multipurpose
- River basin
- South Dakota
- Operator
- USACE
- Coordinates
- 43.307°N, 103.531°W
- Last updated
- September 10, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 10 Sep 2026 | 58.2% | 62 |
| 9 Sep 2026 | 58.0% | 62 |
| 8 Sep 2026 | 58.2% | 62 |
| 7 Sep 2026 | 58.2% | 62 |
| 6 Sep 2026 | 57.7% | 61 |
| 5 Sep 2026 | 57.7% | 61 |
| 4 Sep 2026 | 57.9% | 62 |
| 3 Sep 2026 | 58.2% | 62 |
| 2 Sep 2026 | 58.5% | 62 |
| 1 Sep 2026 | 58.7% | 62 |
| 31 Aug 2026 | 58.6% | 62 |
| 30 Aug 2026 | 58.9% | 63 |