Rivermatics

2 USGS Streamgages · Columbia River system

Coast Fork Willamette River flows and levels

Coast Fork Willamette River is gauged at 2 USGS streamgages in Oregon, each tracked by Rivermatics. The mainstem runs about 50 miles (80 km) from headwaters to outlet. It drains into the Columbia River system. Drainage area at the gauges ranges from 104 square miles at Coast Fork Willamette River below Cottage Grove Dam, OR up to 642 at Coast Fork Willamette River near Goshen, OR. Rivermatics issues a daily machine-learned 14-day flow outlook for every one of them.

Gauges on this river, upstream to downstream

Ordered by drainage area, which is how far down the river each gauge sits. April and July figures are long-term median daily flows for that month from the USGS record — historical normals, not a forecast and not today's reading.

USGS streamgages on this river, ordered upstream to downstream
Gauge State Drainage sq mi Elevation ft April p50 cfs July p50 cfs Forecast
Coast Fork Willamette River below Cottage Grove Dam, OR OR 104 — 114.9 52.5 14-day + temp
Coast Fork Willamette River near Goshen, OR OR 642 — 1,240.6 195.6 14-day + temp

Typical flow by month at Coast Fork Willamette River near Goshen, OR

The furthest-downstream gauge on this river, so the fullest flow it carries here. Long-term daily discharge percentiles from the USGS record (up to 120 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 693.5 2,471.9 7,858.4
February 543.4 1,712.8 6,050.3
March 531.4 1,565.5 4,935.8
April 467.3 1,240.6 3,289
May 332.8 615.6 2,389.4
June 236.5 387.3 1,238.9
July 145.4 195.6 390.1
August 130.4 179.4 767.7
September 159 478.7 942.6
October 201.1 751 1,412.9
November 204.5 957.8 4,379.7
December 455.7 2,141 7,439.7

All values in cubic feet per second (cfs).

Common questions

When does the Coast Fork Willamette River run highest?
January, on the long-term record at Coast Fork Willamette River near Goshen, OR — the furthest-downstream gauge Rivermatics tracks on this river. Median daily flow there is about 2,471.9 cfs that month, against 179.4 cfs in August, the lowest. Upstream gauges peak on their own schedule; the table on this page gives April and July for each.
How many gauges are on the Coast Fork Willamette River?
Rivermatics tracks 2 USGS streamgages on the Coast Fork Willamette River, across Oregon. Each has its own page with the site's full flow record and monthly normals. The river may carry other gauges that publish neither daily values nor discharge statistics; those are not tracked here.
Is there a flow forecast for the Coast Fork Willamette River?
Yes, at 2 of the 2 gauges. Rivermatics trains a machine-learned model — a temporal-fusion transformer — on each basin's observed flows, weather and snowpack, and issues a daily 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 each gauge's live screen.
What river system is the Coast Fork Willamette River part of?
The Coast Fork Willamette River drains into the Columbia River system — it is a tributary somewhere in that chain, following the flowpath down to its terminal river. Rivermatics builds this from the USGS/geoconnex reference-mainstem network rather than from names.
Can I use Coast Fork Willamette River 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.

Other rivers in the Columbia River system

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