Rivermatics

USGS Streamgage 11481000

Mad River near Arcata, CA

Mad River near Arcata, CA is USGS streamgage 11481000 in California, monitoring river discharge in hydrologic subbasin 18010102. It sits on the Mad River, alongside 2 other gauges Rivermatics tracks on the same river. It drains a watershed of about 485 square miles. Discharge records at this site go back to 1911. Typical flow runs near 61.3 cfs in July and 1,287 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
California
Drainage area
485 sq mi
Gauge elevation
14 ft
Subbasin (HUC-8)
18010102
Coordinates
40.90982, -124.06058
USGS site number
11481000
Records begin
1911-01-19 (115 years)
Rivermatics forecast
14-day flow outlook

14-day flow forecast

Based on observations through for Mad River near Arcata, CA. 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
34.3 36.1 38.3
33.4 35.6 38.1
32.8 35 37.7
32.1 34.6 37.5
31.6 34.2 37.3
31.3 34.1 37.3
30.9 33.8 37
29.9 33 36.4
29.4 32.6 36.1
29.4 32.8 36.6
29.5 33.1 37.3
30 33.7 38.2
30.1 34 38.9
29.9 33.9 39

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 64 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 282.3 1,960.3 8,613.9
February 465.6 1,896.9 7,313.4
March 524.2 2,031.6 6,251.3
April 344.6 1,287 3,748
May 150.2 475 1,543.2
June 58.6 141.8 529.7
July 26.6 61.3 113.4
August 18.2 43.3 71.4
September 21.9 43.4 88.3
October 30.2 62.1 321.5
November 53.6 302.6 2,896.2
December 128.1 1,277.2 7,048.1

All values in cubic feet per second (cfs).

Common questions

When does Mad River near Arcata, CA normally run highest?
March, on the long-term record. The median daily flow that month is about 2,031.6 cfs, against 43.3 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 Mad River near Arcata, CA?
It depends on the month. In January, half of days historically fall near 1,960.3 cfs, with the middle 80% of days between 282.3 and 8,613.9 cfs. The month-by-month table on this page gives the full range.
How long has Mad River near Arcata, CA been measured?
Discharge records at USGS site 11481000 begin in 1911, about 115 years, covering roughly 9,130 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
Is there a flow forecast for Mad River near Arcata, CA?
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 Mad River near Arcata, CA?
The gauge sits at 40.90982, -124.06058, in California, in hydrologic subbasin 18010102, at an elevation of about 14 feet, draining roughly 485 square miles.
Can I use Mad River near Arcata, CA 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 Mad River

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

Other gauges in this subbasin