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 2026-10-13); streamflow classes place each USGS gauge's latest reading against its own day-of-year record.
Health score
72
Moderate
Drought index
0
None
Area in D2+
0%
0% exceptional (D4)
Gauges below normal
50%
of 4 reporting
Median flow
251%
p42 of record
Water assets
729
0 springs · 418 wells
USGS gauges (5)
- ILLINOIS RIVER AT MARSEILLES, IL055435004,070 cfsp24 · below normal
- ILLINOIS RIVER AT MORRIS, IL055425003,460 cfsp25 · below normal
- MAZON RIVER NEAR COAL CITY, IL0554200033 cfsp59 · normal
- AUX SABLE CREEK NEAR MORRIS, IL05541710102 cfsp86 · above normal
- HANSON GRAVEL PIT AT CULVERT NEAR MORRIS, IL411955088280601-76 cfsno long-term record
Recent conditions
| Date | DSCI | D2+ % | Gauges low | Flow pct |
|---|---|---|---|---|
| 2026-10-21 | 0 | 0 | 2/4 | p42 |
| 2026-10-20 | 0 | 0 | 0/4 | p60 |
| 2026-10-19 | 0 | 0 | 0/4 | p54 |
| 2026-10-18 | 0 | 0 | 0/4 | p74 |
| 2026-10-17 | 0 | 0 | 0/4 | p70 |
| 2026-10-16 | 0 | 0 | 0/4 | p52 |
| 2026-10-15 | 0 | 0 | 1/4 | p42 |
| 2026-10-14 | 0 | 0 | 0/4 | p54 |
| 2026-10-13 | 0 | 0 | 0/4 | p58 |
| 2026-10-12 | 0 | 0 | 0/4 | p57 |
| 2026-10-11 | 0 | 0 | 0/4 | p54 |
| 2026-10-10 | 0 | 0 | 0/4 | p74 |
| 2026-10-09 | 0 | 0 | 0/4 | p67 |
| 2026-10-08 | 0 | 0 | 0/4 | p72 |
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