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 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.
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)
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.
| 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 9,126 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
- 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.