USGS Streamgage 11469000
Mattole River near Petrolia, CA
Mattole River near Petrolia, CA is USGS streamgage 11469000 in California, monitoring river discharge in hydrologic subbasin 18010107. It sits on the Mattole River, alongside 1 other gauge Rivermatics tracks on the same river. It drains a watershed of about 245 square miles. Discharge records at this site go back to 1911. Typical flow runs near 68.9 cfs in July and 691.4 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
- 245 sq mi
- Gauge elevation
- 50 ft
- Subbasin (HUC-8)
- 18010107
- Coordinates
- 40.31316, -124.28335
- USGS site number
- 11469000
- Records begin
- 1911-10-01 (115 years)
- Rivermatics forecast
- 14-day flow outlook
14-day flow forecast
Based on observations through for Mattole River near Petrolia, 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.
| Date | Low p10 | Expected p50 | High p90 | Range |
|---|---|---|---|---|
| 23.4 | 24.4 | 25.3 | ||
| 22.6 | 23.9 | 25 | ||
| 21.9 | 23.3 | 24.7 | ||
| 21.4 | 22.9 | 24.4 | ||
| 20.9 | 22.5 | 24.2 | ||
| 20.4 | 22.2 | 24 | ||
| 20 | 21.9 | 23.8 | ||
| 19.7 | 21.7 | 23.7 | ||
| 19.5 | 21.6 | 23.8 | ||
| 19.3 | 21.6 | 24 | ||
| 19.2 | 21.6 | 24.4 | ||
| 19 | 21.5 | 24.2 | ||
| 18.8 | 21.4 | 24.3 | ||
| 18.6 | 21.3 | 24.4 |
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 115 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 | 329.2 | 1,671.3 | 8,481.9 | |
| February | 402.3 | 1,553.8 | 7,432.8 | |
| March | 418.2 | 1,379.3 | 5,177.4 | |
| April | 267 | 691.4 | 2,713 | |
| May | 166.2 | 316.1 | 990.2 | |
| June | 82.7 | 143.4 | 375.8 | |
| July | 40.8 | 68.9 | 139.9 | |
| August | 23.7 | 38.7 | 67.2 | |
| September | 18.6 | 30.5 | 71.3 | |
| October | 21.6 | 47.9 | 434 | |
| November | 47.6 | 315.1 | 3,099 | |
| December | 121 | 1,203.3 | 7,377.4 |
All values in cubic feet per second (cfs).
Common questions
- When does Mattole River near Petrolia, CA normally run highest?
- January, on the long-term record. The median daily flow that month is about 1,671.3 cfs, against 30.5 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 Mattole River near Petrolia, CA?
- It depends on the month. In January, half of days historically fall near 1,671.3 cfs, with the middle 80% of days between 329.2 and 8,481.9 cfs. The month-by-month table on this page gives the full range.
- How long has Mattole River near Petrolia, CA been measured?
- Discharge records at USGS site 11469000 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 Mattole River near Petrolia, 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 Mattole River near Petrolia, CA?
- The gauge sits at 40.31316, -124.28335, in California, in hydrologic subbasin 18010107, at an elevation of about 50 feet, draining roughly 245 square miles.
- Can I use Mattole River near Petrolia, 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 Mattole River
Every gauge Rivermatics tracks on this river, ordered by drainage area — upstream first. See the Mattole River in full.
- Mattole River near Ettersburg, CA 71 sq mi
- Mattole River near Petrolia, CA this page