Reservoir · South Dakota · United States · USACE CWMS
Deerfield Reservoir
86.2% full
Capacity
19.31 hm³
Volume stored
17 hm³
Vs month average
91% of normal
Coordinates
44.029°N, 103.786°W
Last updated
2026-10-15
Current fill
86.2%vs 7 days ago
-1.8%losing
vs 1 year ago
-7.0%year-over-year
7-day trend
↓falling
Drought context
Storage vs October average
91%of normal
86.2% full on 2026-10-15, against an average of 94.3% for October across 6 years of readings (-8.1 points).
Drought Monitor at this site · 13 October 2026
D1moderate drought
The ground at Deerfield Reservoir's coordinates falls inside the D1 area of 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: 2026-10-15.
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 15, 2026, Deerfield Reservoir is filled to 86.2% 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 fallen by 1.8 percentage points, and it is 7.0 points below its level on the same date a year earlier.
Across the readings we hold for Deerfield Reservoir — 1818 data points between October 16, 2021 and October 15, 2026 — the level has ranged from a low of 86.2% (October 15, 2026) to a high of 101.8% (July 2, 2023). On average the reservoir is fullest around June and at its lowest around October.
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
- 86.2%
- Water stored
- 17 hm³
- Total capacity
- 19 hm³
- 7-day change
- ▼ 1.8 pts
- Year-on-year
- ▼ 7.0 pts
- Primary use
- Multipurpose
- River basin
- South Dakota
- Operator
- USACE
- Coordinates
- 44.029°N, 103.786°W
- Last updated
- October 15, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 15 Oct 2026 | 86.2% | 17 |
| 14 Oct 2026 | 86.4% | 17 |
| 13 Oct 2026 | 86.6% | 17 |
| 12 Oct 2026 | 86.9% | 17 |
| 11 Oct 2026 | 87.2% | 17 |
| 10 Oct 2026 | 87.5% | 17 |
| 9 Oct 2026 | 87.7% | 17 |
| 8 Oct 2026 | 88.0% | 17 |
| 7 Oct 2026 | 88.3% | 17 |
| 6 Oct 2026 | 88.6% | 17 |
| 5 Oct 2026 | 88.8% | 17 |
| 4 Oct 2026 | 89.1% | 17 |