Rivermatics

USGS Streamgage 14238000

Cowlitz River below Mayfield Dam, WA

Cowlitz River below Mayfield Dam, WA is USGS streamgage 14238000 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 1,400 square miles. Discharge records at this site go back to 1911. Typical flow runs near 3,693.2 cfs in July and 5,790 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
1,400 sq mi
Subbasin (HUC-8)
17080005
Coordinates
46.51039, -122.61622
USGS site number
14238000
Records begin
1911-11-19 (115 years)
Rivermatics forecast
14-day flow outlook

14-day flow forecast

Based on observations through for Cowlitz River below Mayfield Dam, 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
2,389 2,988 3,748
2,251 2,871 4,047
2,219 2,864 4,317
2,227 2,969 4,526
2,213 2,967 4,507
2,197 2,969 4,487
2,197 3,013 4,515
2,185 3,034 4,549
2,177 3,056 4,576
2,140 3,017 4,594
2,155 3,035 4,628
2,154 3,045 4,640
2,180 3,099 4,706
2,152 3,053 4,714

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 92 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 3,883.5 8,158.1 15,067.7
February 3,884.8 6,931.4 13,679.3
March 3,533.2 5,802.9 10,334.2
April 3,402.7 5,790 10,706.7
May 3,179.7 6,250 12,248.4
June 3,142.7 6,035 11,845.3
July 2,251.9 3,693.2 7,241
August 1,697.4 2,603.5 4,059.7
September 1,337.7 2,561 4,231
October 1,411 3,562.9 6,046.5
November 2,546.3 6,342 13,076.7
December 3,841 8,666.8 16,429

All values in cubic feet per second (cfs).

Common questions

When does Cowlitz River below Mayfield Dam, WA normally run highest?
December, on the long-term record. The median daily flow that month is about 8,666.8 cfs, against 2,561 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 below Mayfield Dam, WA?
It depends on the month. In January, half of days historically fall near 8,158.1 cfs, with the middle 80% of days between 3,883.5 and 15,067.7 cfs. The month-by-month table on this page gives the full range.
How long has Cowlitz River below Mayfield Dam, WA been measured?
Discharge records at USGS site 14238000 begin in 1911, about 115 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 below Mayfield Dam, 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 below Mayfield Dam, WA?
The gauge sits at 46.51039, -122.61622, in Washington, in hydrologic subbasin 17080005, draining roughly 1,400 square miles.
Can I use Cowlitz River below Mayfield Dam, 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