Mattole HUC8 18010107
A 1,936 km² sub-basin of the California region in CA. 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
71
Moderate
Drought index
175
Moderate
Area in D2+
0%
0% exceptional (D4)
Gauges below normal
0%
of 2 reporting
Median flow
172%
p81 of record
Water assets
822
0 springs · 2 wells
USGS gauges (2)
- MATTOLE R NR PETROLIA CA1146900050 cfsp80 · above normal
- MATTOLE R NR ETTERSBURG CA1146890011 cfsp82 · above normal
Recent conditions
| Date | DSCI | D2+ % | Gauges low | Flow pct |
|---|---|---|---|---|
| 2026-09-07 | 175 | 0 | 0/2 | p81 |
Top water assets
- 67Nelson Creekriver
- 65Mattole R Nr Petrolia Cariver
- 65Mattole Riverriver
- 65Mattole R Nr Ettersburg Cariver
- 65Mattole Riverriver
- 65Guthrie Creekriver
- 65South Fork Bear Riverriver
- 65Thompson Creekriver
- 65Rattlesnake Creekriver
- 65Upper North Fork Mattole Riverriver