USGS Streamgage 11467510
SF Gualala River near the Sea Ranch, CA
SF Gualala River near the Sea Ranch, CA is USGS streamgage 11467510 in California, monitoring river discharge in hydrologic subbasin 18010109. It drains a watershed of about 161 square miles. Discharge records at this site go back to 1991. Typical flow runs near 5.9 cfs in July and 191 cfs in April, with the higher of the two arriving in April.
Gauge details
- State
- California
- Drainage area
- 161 sq mi
- Gauge elevation
- 42 ft
- Subbasin (HUC-8)
- 18010109
- Coordinates
- 38.70903, -123.42664
- USGS site number
- 11467510
- Records begin
- 1991-06-01 (35 years)
Typical flow by month
Long-term daily discharge percentiles from the USGS record (up to 35 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 | 17.1 | 279.7 | 3,531.5 | |
| February | 46.3 | 239.4 | 3,557.7 | |
| March | 42.3 | 299.8 | 2,353.2 | |
| April | 28.8 | 191 | 741.1 | |
| May | 14.3 | 56.7 | 225.5 | |
| June | 5.1 | 17.1 | 72.8 | |
| July | 1.4 | 5.9 | 21.9 | |
| August | 0.4 | 2 | 8.7 | |
| September | 0.1 | 1 | 4.8 | |
| October | 0.2 | 2.5 | 250.1 | |
| November | 1.7 | 14.6 | 361.3 | |
| December | 10.2 | 189.3 | 2,460.5 |
All values in cubic feet per second (cfs).
Common questions
- When does SF Gualala River near the Sea Ranch, CA normally run highest?
- March, on the long-term record. The median daily flow that month is about 299.8 cfs, against 1 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 SF Gualala River near the Sea Ranch, CA?
- It depends on the month. In January, half of days historically fall near 279.7 cfs, with the middle 80% of days between 17.1 and 3,531.5 cfs. The month-by-month table on this page gives the full range.
- How long has SF Gualala River near the Sea Ranch, CA been measured?
- Discharge records at USGS site 11467510 begin in 1991, about 35 years, covering roughly 6,880 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
- Where is SF Gualala River near the Sea Ranch, CA?
- The gauge sits at 38.70903, -123.42664, in California, in hydrologic subbasin 18010109, at an elevation of about 42 feet, draining roughly 161 square miles.
- Can I use SF Gualala River near the Sea Ranch, 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.