Reservoir · Illinois · United States · USACE CWMS
Sub
54.2% full
Capacity
15.24 hm³
Volume stored
8 hm³
Vs month average
119% of normal
Coordinates
38.176°N, 89.006°W
Last updated
2026-10-29
Current fill
54.2%vs 7 days ago
+3.4 ppgaining
vs 1 year ago
N/A7-day trend
↑rising
Drought context
Storage vs October average
119%of normal
54.2% full on 2026-10-29, against an average of 45.5% for October across 2 years of readings (+8.7 points).
Drought Monitor at this site · 27 October 2026
D2severe drought
The ground at Sub's coordinates falls inside the D2 area of the weekly U.S. Drought Monitor map. That describes local conditions — rainfall, soil moisture, streamflow — not the reservoir's storage. Illinois drought figures →
Data source: USACE CWMS — US Army Corps of Engineers — daily reservoir storage volume. Design capacity is unavailable for this site, so fill % is estimated against the 5-year maximum storage and may overstate fullness. Last reading: 2026-10-29.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 38.176°N, 89.006°W · Open in Google Maps
About Sub
As of October 29, 2026, Sub is filled to 54.2% of its total capacity, holding 8.26 hm³ of water out of a maximum 15.24 hm³. At this level the reservoir is within its normal operating range.
Over the most recent week on record the fill level has risen by 3.4 percentage points.
Across the readings we hold for Sub — 199 data points between October 30, 2021 and October 29, 2026 — the level has ranged from a low of 21.6% (July 28, 2026) to a high of 100.0% (December 19, 2021). On average the reservoir is fullest around January and at its lowest around July.
It is operated by USACE primarily for multiple purposes. It is at 38.176°N, 89.006°W.
Key facts
- Current fill level
- 54.2% of total capacity
- Water stored
- 8.26 hm³
- Total capacity
- 15.24 hm³
- 7-day change
- ▲ 3.4 pp
- Primary use
- Multipurpose
- Operator
- USACE
- Coordinates
- 38.176°N, 89.006°W
- Last updated
- October 29, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 29 Oct 2026 | 54.2% | 8.26 |
| 28 Oct 2026 | 53.7% | 8.18 |
| 27 Oct 2026 | 52.7% | 8.02 |
| 26 Oct 2026 | 51.5% | 7.85 |
| 25 Oct 2026 | 51.3% | 7.81 |
| 24 Oct 2026 | 51.5% | 7.85 |
| 23 Oct 2026 | 51.7% | 7.88 |
| 22 Oct 2026 | 50.8% | 7.74 |
| 21 Oct 2026 | 49.4% | 7.53 |
| 20 Oct 2026 | 48.2% | 7.34 |
| 19 Oct 2026 | 46.9% | 7.15 |
| 18 Oct 2026 | 46.4% | 7.07 |