Illinois HUC8 17100311
A 2,564 km² sub-basin of the Pacific Northwest region in CA, OR. 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
54
Moderate
Drought index
300
Extreme
Area in D2+
100%
0% exceptional (D4)
Gauges below normal
33%
of 3 reporting
Median flow
105%
p54 of record
Water assets
165
58 springs · 79 wells
USGS gauges (3)
- SUCKER CREEK BLW LITTLE GRAYBACK CK, NR HOLLAND,OR1437510022 cfsp24 · below normal
- ILLINOIS RIVER NEAR KERBY, OR1437710037 cfsp54 · normal
- ILLINOIS RIVER NEAR AGNESS, OR14378200277 cfsp81 · above normal
Recent conditions
| Date | DSCI | D2+ % | Gauges low | Flow pct |
|---|---|---|---|---|
| 2026-09-07 | 300 | 100 | 1/3 | p54 |
Top water assets
- 76Hydraulic Gulch — Miningspring
- 76Run Gulch — Miningspring
- 76South Fork Of Althouse Creek — Miningspring
- 76Althouse Creek — Miningspring
- 76Althouse Creek — Miningspring
- 76Sucker Creek — Miningspring
- 76Browntown Gulch — Miningspring
- 76Althouse Creek — Miningspring
- 76Democrat Gulch — Miningspring
- 76Run Gulch — Miningspring