Rivermatics

USGS Streamgage 12021800

Chehalis River near Adna, WA

Chehalis River near Adna, WA is USGS streamgage 12021800 in Washington, monitoring river discharge in hydrologic subbasin 17100103. It sits on the Chehalis River, alongside 6 other gauges Rivermatics tracks on the same river. It drains a watershed of about 340 square miles. Discharge records at this site go back to 1999. Typical flow runs near 102.4 cfs in July and 1,044.4 cfs in April, with the higher of the two arriving in April. Rivermatics issues a daily machine-learned flow outlook for this gauge, reaching 14 days ahead.

View live conditions & forecast →

Gauge details

State
Washington
Drainage area
340 sq mi
Gauge elevation
194 ft
Subbasin (HUC-8)
17100103
Coordinates
46.62566, -123.1018
USGS site number
12021800
Records begin
1999-10-15 (27 years)
Rivermatics forecast
14-day flow outlook

14-day flow forecast

Based on observations through for Chehalis River near Adna, WA. Each day carries a median estimate and the band the model expects the flow to fall within — not a single number to plan against. Forecasts are re-issued daily; see the live screen for the current outlook.

Forecast daily mean discharge in cubic feet per second, by date
Date Low p10 Expected p50 High p90 Range
49.3 51.6 53.7
47.2 50.4 54.8
49.1 57.4 81.5
50.9 65.4 104
48.6 59.6 83.2
45.3 55.2 77.6
43 51.6 68.2
39.7 47.8 63.7
39 47.8 67.1
38.4 46.8 62.1
37.6 45.4 57.7
37 44.6 55.9
36.2 44.4 57.9
33.8 41.9 55

All values in cubic feet per second (cfs). Estimates only — do not use them for navigation or for any safety, rescue, or emergency decision.

Typical flow by month

Long-term daily discharge percentiles from the USGS record (up to 11 years of data), averaged within each month. These describe the historical normal range — they are not a forecast and not today's reading.

Historical monthly discharge percentiles in cubic feet per second
Month Low p10 Typical p50 High p90 Range
January 881.1 2,421.3 9,673.2
February 731.7 1,634.5 6,605.7
March 762.6 1,491.6 4,924.2
April 499.8 1,044.4 3,507.3
May 225.5 413.1 1,276.1
June 117.2 229.6 795.6
July 58 102.4 199.5
August 35.1 53.4 91.6
September 35.2 59.9 278.4
October 75.8 211.4 2,358.5
November 229.9 1,550.7 6,909
December 704.9 2,194.5 8,569

All values in cubic feet per second (cfs).

Common questions

When does Chehalis River near Adna, WA normally run highest?
January, on the long-term record. The median daily flow that month is about 2,421.3 cfs, against 53.4 cfs in August, the lowest month. These are historical normals for the date, not a forecast and not today's reading.
What is a normal flow for Chehalis River near Adna, WA?
It depends on the month. In January, half of days historically fall near 2,421.3 cfs, with the middle 80% of days between 881.1 and 9,673.2 cfs. The month-by-month table on this page gives the full range.
How long has Chehalis River near Adna, WA been measured?
Discharge records at USGS site 12021800 begin in 1999, about 27 years, covering roughly 3,962 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
Is there a flow forecast for Chehalis River near Adna, WA?
Yes. Rivermatics trains a machine-learned model — a temporal-fusion transformer — on this basin's observed flows, weather, and snowpack, and issues a daily flow outlook reaching 14 days ahead: a median estimate inside a confidence band, not a single number to bet on. Every forecast is scored against days the model never trained on, and that track record is published on the live gauge screen. Open live conditions to see the current outlook.
Where is Chehalis River near Adna, WA?
The gauge sits at 46.62566, -123.1018, in Washington, in hydrologic subbasin 17100103, at an elevation of about 194 feet, draining roughly 340 square miles.
Can I use Chehalis River near Adna, WA data for flood or safety decisions?
No. Rivermatics provides estimates, not guarantees, and the readings and forecasts here may be delayed, inaccurate, or wrong. Do not use them for navigation or for any safety, rescue, or emergency decision. Check the National Weather Service and USGS directly, and use your own judgment.

Upstream and downstream on the Chehalis River

Every gauge Rivermatics tracks on this river, ordered by drainage area — upstream first. See the Chehalis River in full.

Other gauges in this subbasin