Reservoir · South Dakota · United States · USACE CWMS
Deerfield Reservoir
89.8% full
Capacity
19.31 hm³
Volume stored
17 hm³
Coordinates
44.029°N, 103.786°W
Last updated
2026-10-01
Current fill
89.8%vs 7 days ago
-0.3%losing
vs 1 year ago
-3.5%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: 2026-10-01.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 44.029, -103.786 · Open in Google Maps
About Deerfield Reservoir
As of October 1, 2026, Deerfield Reservoir is filled to 89.8% of its total capacity, holding roughly 17 hm³ of water out of a maximum 19 hm³. At this level the reservoir is high.
Over the most recent week on record the fill level has held broadly steady (-0.3 pts), and it is 3.5 points below its level on the same date a year earlier.
Across the readings we hold for Deerfield Reservoir — 1818 data points between October 2, 2021 and October 1, 2026 — the level has ranged from a low of 87.4% (July 11, 2025) to a high of 101.8% (July 2, 2023). 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 44.029°N, 103.786°W.
Key facts
- Current fill level
- 89.8%
- Water stored
- 17 hm³
- Total capacity
- 19 hm³
- 7-day change
- ▼ 0.3 pts
- Year-on-year
- ▼ 3.5 pts
- Primary use
- Multipurpose
- River basin
- South Dakota
- Operator
- USACE
- Coordinates
- 44.029°N, 103.786°W
- Last updated
- October 1, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 1 Oct 2026 | 89.8% | 17 |
| 30 Sep 2026 | 89.8% | 17 |
| 29 Sep 2026 | 89.9% | 17 |
| 28 Sep 2026 | 89.9% | 17 |
| 27 Sep 2026 | 90.0% | 17 |
| 26 Sep 2026 | 90.0% | 17 |
| 25 Sep 2026 | 90.1% | 17 |
| 24 Sep 2026 | 90.1% | 17 |
| 23 Sep 2026 | 90.1% | 17 |
| 22 Sep 2026 | 90.1% | 17 |
| 21 Sep 2026 | 90.0% | 17 |
| 20 Sep 2026 | 89.8% | 17 |