Rivermatics

USGS Streamgage 14243000

Cowlitz River at Castle Rock, WA

Cowlitz River at Castle Rock, WA is USGS streamgage 14243000 in Washington, monitoring river discharge in hydrologic subbasin 17080005. It sits on the Cowlitz River, alongside 5 other gauges Rivermatics tracks on the same river. It drains a watershed of about 2,238 square miles. Discharge records at this site go back to 1926. Typical flow runs near 4,527.7 cfs in July and 9,161.7 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.

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Gauge details

State
Washington
Drainage area
2,238 sq mi
Subbasin (HUC-8)
17080005
Coordinates
46.27483, -122.91456
USGS site number
14243000
Records begin
1926-12-10 (100 years)
Rivermatics forecast
14-day flow outlook

14-day flow forecast

Based on observations through for Cowlitz River at Castle Rock, 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
3,388 4,079 4,576
3,025 4,073 4,977
2,736 3,888 5,243
2,823 4,009 5,587
2,793 4,030 5,664
2,799 4,102 5,813
2,772 4,106 5,767
2,759 4,143 5,859
2,741 4,131 5,844
2,673 4,081 5,863
2,643 4,050 5,851
2,656 4,077 5,910
2,668 4,089 5,925
2,609 4,028 5,914

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 99 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 5,960 12,451.6 25,461.3
February 5,781.4 11,027.6 22,631
March 5,784.8 9,609.4 17,800
April 5,990 9,161.7 15,996.7
May 5,111.6 9,642.6 16,032.3
June 4,218.3 8,376.3 15,233.3
July 2,778.7 4,527.7 9,069.7
August 2,098.7 2,999.4 4,651.6
September 1,692.3 2,877 4,809
October 1,776.1 4,304.2 8,113.5
November 3,400.3 8,998.7 20,400
December 5,619.7 12,561.3 26,174.2

All values in cubic feet per second (cfs).

Common questions

When does Cowlitz River at Castle Rock, WA normally run highest?
December, on the long-term record. The median daily flow that month is about 12,561.3 cfs, against 2,877 cfs in September, the lowest month. These are historical normals for the date, not a forecast and not today's reading.
What is a normal flow for Cowlitz River at Castle Rock, WA?
It depends on the month. In January, half of days historically fall near 12,451.6 cfs, with the middle 80% of days between 5,960 and 25,461.3 cfs. The month-by-month table on this page gives the full range.
How long has Cowlitz River at Castle Rock, WA been measured?
Discharge records at USGS site 14243000 begin in 1926, about 100 years, covering roughly 9,200 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
Is there a flow forecast for Cowlitz River at Castle Rock, 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 Cowlitz River at Castle Rock, WA?
The gauge sits at 46.27483, -122.91456, in Washington, in hydrologic subbasin 17080005, draining roughly 2,238 square miles.
Can I use Cowlitz River at Castle Rock, 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 Cowlitz River

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

Other gauges in this subbasin