Reservoir · Illinois · United States · USACE CWMS
Sub
71.0% full
Capacity
4.86 hm³
Volume stored
4 hm³
Coordinates
38.176°N, 89.006°W
Last updated
2026-07-31
Current fill
71.0%vs 7 days ago
0.0%stable
vs 1 year ago
-11.9%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: 2026-07-31.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 38.176, -89.006 · Open in Google Maps
About Sub
As of July 31, 2026, Sub is filled to 71.0% of its total capacity, holding roughly 4 hm³ of water out of a maximum 5 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 11.9 points below its level on the same date a year earlier.
Across the readings we hold for Sub — 93 data points between April 29, 2026 and July 31, 2026 — the level has ranged from a low of 67.9% (July 28, 2026) to a high of 105.0% (April 29, 2026).
It is operated by USACE primarily for multiple purposes. It lies within the Illinois basin at 38.176°N, 89.006°W.
Key facts
- Current fill level
- 71.0%
- Water stored
- 4 hm³
- Total capacity
- 5 hm³
- 7-day change
- No change
- Year-on-year
- ▼ 11.9 pts
- Primary use
- Multipurpose
- River basin
- Illinois
- Operator
- USACE
- Coordinates
- 38.176°N, 89.006°W
- Last updated
- July 31, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 31 Jul 2026 | 71.0% | 3 |
| 30 Jul 2026 | 71.0% | 3 |
| 29 Jul 2026 | 67.9% | 3 |
| 28 Jul 2026 | 67.9% | 3 |
| 27 Jul 2026 | 68.9% | 3 |
| 26 Jul 2026 | 69.3% | 3 |
| 25 Jul 2026 | 69.8% | 3 |
| 24 Jul 2026 | 69.5% | 3 |
| 23 Jul 2026 | 70.8% | 3 |
| 22 Jul 2026 | 70.8% | 3 |
| 21 Jul 2026 | 72.0% | 4 |
| 20 Jul 2026 | 76.3% | 4 |
Frequently asked questions
What is the current water level of Sub?
As of July 31, 2026, Sub is at 71.0% of its capacity, holding approximately 4 hm³ of water, according to USACE CWMS (US Army Corps of Engineers) data.
Is Sub reservoir full?
No. As of July 31, 2026, Sub is within its normal operating range at 71.0% of its capacity, so it is not full.
Is the water level at Sub rising or falling?
The level at Sub has been broadly stable over the latest week on record (0.0 points).
How much water can Sub hold?
Sub has a total capacity of 5 hm³.
Where is Sub reservoir located?
Sub is located in Illinois, United States, within the Illinois basin (coordinates 38.176°N, 89.006°W).
What is Sub used for?
Sub is used primarily for multiple purposes, and is managed by USACE.