Lower Chehalis HUC8 17100104
A 2,120 km² sub-basin of the Pacific Northwest region in WA. 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
59
Moderate
Drought index
21
Abnormally dry
Area in D2+
0%
0% exceptional (D4)
Gauges below normal
100%
of 4 reporting
Median flow
44%
p17 of record
Water assets
352
15 springs · 285 wells
USGS gauges (6)
- WYNOOCHEE RIVER ABOVE SAVE CREEK NEAR ABERDEEN, WA12036000216 cfsp14 · below normal
- SATSOP RIVER NEAR SATSOP, WA12035000286 cfsp16 · below normal
- WYNOOCHEE RIVER NEAR GRISDALE, WA12035400204 cfsp18 · below normal
- WYNOOCHEE RIVER ABOVE BLACK CREEK NR MONTESANO, WA12037400216 cfsp25 · below normal
- BIG CREEK NEAR GRISDALE, WA1203545015 cfsno long-term record
- SCHAFER CREEK NEAR GRISDALE, WA120364006 cfsno long-term record
Recent conditions
| Date | DSCI | D2+ % | Gauges low | Flow pct |
|---|---|---|---|---|
| 2026-10-19 | 21 | 0 | 4/4 | p17 |
| 2026-10-18 | 21 | 0 | 4/4 | p17 |
| 2026-10-17 | 21 | 0 | 4/4 | p18 |
| 2026-10-16 | 21 | 0 | 4/4 | p19 |
| 2026-10-15 | 21 | 0 | 4/4 | p20 |
| 2026-10-14 | 21 | 0 | 4/4 | p19 |
| 2026-10-13 | 21 | 0 | 2/4 | p23 |
| 2026-10-12 | 21 | 0 | 2/4 | p23 |
| 2026-10-11 | 21 | 0 | 2/4 | p24 |
| 2026-10-10 | 21 | 0 | 2/4 | p25 |
| 2026-10-09 | 21 | 0 | 2/4 | p26 |
| 2026-10-08 | 21 | 0 | 2/4 | p28 |
| 2026-10-07 | 21 | 0 | 2/4 | p31 |
| 2026-10-06 | 21 | 0 | 2/4 | p34 |
Top water assets
- 67Wynoocheereservoir
- 66Ci Dm Ir St — Ap S2-29714spring
- 65Wynoochee River Above Save Creek Near Aberdeen, Wariver
- 65Satsop River Near Satsop, Wariver
- 65Fairview Reservoir No 2reservoir
- 65Wynoochee River Near Grisdale, Wariver
- 65Big Creek Near Grisdale, Wariver
- 65Fairview Reservoir No 1reservoir
- 65Wynoochee River Above Black Creek Nr Montesano, Wariver
- 65Malinowski Damreservoir