USGS Streamgage 11480390
Mad River Ab Ruth Reservoir near Forest Glen, CA
Mad River Ab Ruth Reservoir near Forest Glen, CA is USGS streamgage 11480390 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 94 square miles. Discharge records at this site go back to 1980. Typical flow runs near 3.2 cfs in July and 176.3 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
- 94 sq mi
- Gauge elevation
- 2,669 ft
- Subbasin (HUC-8)
- 18010102
- Coordinates
- 40.28428, -123.33527
- USGS site number
- 11480390
- Records begin
- 1980-06-20 (46 years)
- Rivermatics forecast
- 14-day flow outlook
14-day flow forecast
Based on observations through for Mad River Ab Ruth Reservoir near Forest Glen, 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 |
|---|---|---|---|---|
| 0 | 0 | 0 | ||
| 0 | 0 | 0.1 | ||
| 0 | 0 | 0 | ||
| 0 | 0 | 0.1 | ||
| 0 | 0 | 0.1 | ||
| 0 | 0 | 0.1 | ||
| 0 | 0 | 0.1 | ||
| 0 | 0 | 0.1 | ||
| 0 | 0 | 0.1 | ||
| 0 | 0 | 0.1 | ||
| 0 | 0 | 0.1 | ||
| 0 | 0 | 0.1 | ||
| 0 | 0 | 0.1 | ||
| 0 | 0 | 0.1 |
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 46 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 | 32.9 | 290.1 | 1,554.8 | |
| February | 54.9 | 312.4 | 1,507.5 | |
| March | 55.6 | 305.1 | 1,240.8 | |
| April | 39.7 | 176.3 | 680.8 | |
| May | 20.8 | 59.3 | 241.5 | |
| June | 5.8 | 18.3 | 86.5 | |
| July | 0.9 | 3.2 | 16.2 | |
| August | 0 | 0.4 | 2.8 | |
| September | 0 | 0 | 1.5 | |
| October | 0 | 0 | 28 | |
| November | 0 | 16.7 | 359.2 | |
| December | 9.7 | 139.7 | 1,506 |
All values in cubic feet per second (cfs).
Common questions
- When does Mad River Ab Ruth Reservoir near Forest Glen, CA normally run highest?
- February, on the long-term record. The median daily flow that month is about 312.4 cfs, against 0 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 Mad River Ab Ruth Reservoir near Forest Glen, CA?
- It depends on the month. In January, half of days historically fall near 290.1 cfs, with the middle 80% of days between 32.9 and 1,554.8 cfs. The month-by-month table on this page gives the full range.
- How long has Mad River Ab Ruth Reservoir near Forest Glen, CA been measured?
- Discharge records at USGS site 11480390 begin in 1980, about 46 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 Ab Ruth Reservoir near Forest Glen, 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 Ab Ruth Reservoir near Forest Glen, CA?
- The gauge sits at 40.28428, -123.33527, in California, in hydrologic subbasin 18010102, at an elevation of about 2,669 feet, draining roughly 94 square miles.
- Can I use Mad River Ab Ruth Reservoir near Forest Glen, 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.
- Mad River Ab Ruth Reservoir near Forest Glen, CA this page
- Mad River below Ruth Reservoir near Forest Glen, CA 121 sq mi
- Mad River near Arcata, CA 485 sq mi