USGS Streamgage 12027500
Chehalis River near Grand Mound, WA
Chehalis River near Grand Mound, WA is USGS streamgage 12027500 in Washington, monitoring river discharge in hydrologic subbasin 17100103. It drains a watershed of about 895 square miles. Discharge records at this site go back to 1928. Typical flow runs near 350.7 cfs in July and 2,347 cfs in April, with the higher of the two arriving in April.
Gauge details
- State
- Washington
- Drainage area
- 895 sq mi
- Gauge elevation
- 132 ft
- Subbasin (HUC-8)
- 17100103
- Coordinates
- 46.77593, -123.03569
- USGS site number
- 12027500
- Records begin
- 1928-10-01 (98 years)
Typical flow by month
Long-term daily discharge percentiles from the USGS record (up to 98 years of data), averaged within each month. These describe the historical normal range — they are not a forecast and not today's reading.
| Month | Low p10 | Typical p50 | High p90 | Range |
|---|---|---|---|---|
| January | 1,658.7 | 4,633.5 | 14,348.4 | |
| February | 1,642.4 | 3,899.3 | 12,247.9 | |
| March | 1,544.8 | 3,428.4 | 9,288.4 | |
| April | 1,193 | 2,347 | 5,769.3 | |
| May | 685.2 | 1,151.5 | 2,606.5 | |
| June | 390.8 | 665 | 1,442.9 | |
| July | 215.1 | 350.7 | 564.5 | |
| August | 141.2 | 218.1 | 353.3 | |
| September | 151.6 | 249.8 | 609.7 | |
| October | 216 | 492.3 | 2,136.4 | |
| November | 522.7 | 2,451 | 9,424.3 | |
| December | 1,348.9 | 4,231.9 | 14,193.5 |
All values in cubic feet per second (cfs).
Other gauges in this subbasin
- Chehalis River near Rochester, WA
- Chehalis River at Porter, WA
- Chehalis River near Doty, WA
- Elk Creek below Deer Creek near Doty, WA
- South Fork Chehalis River near Wildwood, WA
- Chehalis River near Adna, WA
- South Fork Newaukum River near Onalaska, WA
- NF Newaukum River above Bear Creek near Forest, WA