Upper Illinois HUC8 07120005
A 2,606 km² sub-basin of the Upper Mississippi region in IL. Drought coverage is from the US Drought Monitor (map of 2026-09-01); streamflow classes place each USGS gauge's latest reading against its own day-of-year record.
Health score
78
Healthy
Drought index
0
None
Area in D2+
0%
0% exceptional (D4)
Gauges below normal
25%
of 4 reporting
Median flow
121%
p53 of record
Water assets
729
0 springs · 418 wells
USGS gauges (5)
- ILLINOIS RIVER AT MARSEILLES, IL055435004,450 cfsp20 · below normal
- AUX SABLE CREEK NEAR MORRIS, IL0554171017 cfsp49 · normal
- MAZON RIVER NEAR COAL CITY, IL0554200011 cfsp56 · normal
- ILLINOIS RIVER AT MORRIS, IL055425005,930 cfsp69 · normal
- HANSON GRAVEL PIT AT CULVERT NEAR MORRIS, IL411955088280601-76 cfsno long-term record
Recent conditions
| Date | DSCI | D2+ % | Gauges low | Flow pct |
|---|---|---|---|---|
| 2026-09-07 | 0 | 0 | 1/4 | p53 |
Top water assets
- 66Bazzoni Lake Damreservoir
- 66Lasalle Co. Nuclear Station Cooling Lake Damreservoir
- 65Braidwood Station Cooling Pond Damreservoir
- 65Hickory Lake Damreservoir
- 65Mazon River Near Coal City, Ilriver
- 65Grande Park Subdivision Detention As-7 Damreservoir
- 65Illinois Riverriver
- 65International Center South Damreservoir
- 65Collins Station Cooling Lake Damreservoir
- 65Marseilles Lock And Damreservoir