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 2026-10-13); streamflow classes place each USGS gauge's latest reading against its own day-of-year record.
Health score
66
Moderate
Drought index
100
Moderate
Area in D2+
0%
0% exceptional (D4)
Gauges below normal
50%
of 2 reporting
Median flow
50%
p19 of record
Water assets
822
0 springs · 2 wells
USGS gauges (2)
- MATTOLE R NR PETROLIA CA1146900016 cfsp7 · much below normal
- MATTOLE R NR ETTERSBURG CA114689007 cfsp31 · normal
Recent conditions
| Date | DSCI | D2+ % | Gauges low | Flow pct |
|---|---|---|---|---|
| 2026-10-20 | 100 | 0 | 1/2 | p19 |
| 2026-10-19 | 100 | 0 | 2/2 | p13 |
| 2026-10-18 | 100 | 0 | 2/2 | p14 |
| 2026-10-17 | 100 | 0 | 1/2 | p16 |
| 2026-10-16 | 100 | 0 | 1/2 | p18 |
| 2026-10-15 | 100 | 0 | 1/2 | p17 |
| 2026-10-14 | 100 | 0 | 2/2 | p13 |
| 2026-10-13 | 100 | 0 | 2/2 | p13 |
| 2026-10-12 | 100 | 0 | 2/2 | p12 |
| 2026-10-11 | 100 | 0 | 2/2 | p14 |
| 2026-10-10 | 100 | 0 | 2/2 | p15 |
| 2026-10-09 | 100 | 0 | 1/2 | p19 |
| 2026-10-08 | 100 | 0 | 1/2 | p22 |
| 2026-10-07 | 100 | 0 | 1/2 | p22 |
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