Rivermatics

USGS Streamgage 14203500

Tualatin River near Dilley, OR

Tualatin River near Dilley, OR is USGS streamgage 14203500 in Oregon, monitoring river discharge in hydrologic subbasin 17090010. It sits on the Tualatin River, alongside 4 other gauges Rivermatics tracks on the same river. It drains a watershed of about 125 square miles. Discharge records at this site go back to 1939. Typical flow runs near 117.4 cfs in July and 305.1 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, alongside daily high and low water-temperature forecasts.

View live conditions & forecast →

Gauge details

State
Oregon
Drainage area
125 sq mi
Subbasin (HUC-8)
17090010
Coordinates
45.47484, -123.12427
USGS site number
14203500
Records begin
1939-10-01 (87 years)
Rivermatics forecast
14-day flow outlook + water temperature

14-day flow forecast

Based on observations through for Tualatin River near Dilley, OR. 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
172 182 196
166 190 225
156 186 235
149 182 230
146 182 229
144 183 232
142 182 227
143 183 227
141 184 229
137 184 231
137 184 232
130 181 227
132 182 227
137 185 231

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 87 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 207.7 737 1,955.2
February 189.4 575.3 1,679.3
March 199.3 505.4 1,207.6
April 130.5 305.1 717.5
May 90.4 149.9 332.9
June 53 98.6 195.7
July 16.7 117.4 225.7
August 5.9 140.6 244.1
September 9.2 117.4 225.9
October 20.1 108.8 226.5
November 57.8 214.3 859.4
December 126.4 569.5 1,764.2

All values in cubic feet per second (cfs).

Common questions

When does Tualatin River near Dilley, OR normally run highest?
January, on the long-term record. The median daily flow that month is about 737 cfs, against 98.6 cfs in June, the lowest month. These are historical normals for the date, not a forecast and not today's reading.
What is a normal flow for Tualatin River near Dilley, OR?
It depends on the month. In January, half of days historically fall near 737 cfs, with the middle 80% of days between 207.7 and 1,955.2 cfs. The month-by-month table on this page gives the full range.
How long has Tualatin River near Dilley, OR been measured?
Discharge records at USGS site 14203500 begin in 1939, about 87 years, covering roughly 9,201 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
Is there a flow forecast for Tualatin River near Dilley, OR?
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. A companion model forecasts each day's water-temperature high and low. 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 Tualatin River near Dilley, OR?
The gauge sits at 45.47484, -123.12427, in Oregon, in hydrologic subbasin 17090010, draining roughly 125 square miles.
Can I use Tualatin River near Dilley, OR 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 Tualatin River

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

Other gauges in this subbasin