USGS Streamgage 11254000
San Joaquin River near Mendota, CA
San Joaquin River near Mendota, CA is USGS streamgage 11254000 in California, monitoring river discharge in hydrologic subbasin 18040001. It drains a watershed of about 3,940 square miles. Discharge records at this site go back to 1939. Typical flow runs near 1,556.8 cfs in July and 4,272 cfs in April, with the higher of the two arriving in April.
Gauge details
- State
- California
- Drainage area
- 3,940 sq mi
- Gauge elevation
- 133 ft
- Subbasin (HUC-8)
- 18040001
- Coordinates
- 36.8105, -120.37823
- USGS site number
- 11254000
- Records begin
- 1939-10-01 (87 years)
Typical flow by month
Long-term daily discharge percentiles from the USGS record (up to 82 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 | — | 936.5 | — | |
| February | 82 | 454.6 | 6,620 | |
| March | — | 2,853.9 | — | |
| April | — | 4,272 | — | |
| May | — | 4,128.7 | — | |
| June | — | 3,248 | — | |
| July | — | 1,556.8 | — | |
| August | — | 562.2 | — | |
| September | 162.9 | 309.5 | 391.7 | |
| October | — | 311.9 | — | |
| November | — | 346.9 | — | |
| December | — | 414.4 | — |
All values in cubic feet per second (cfs).
Common questions
- When does San Joaquin River near Mendota, CA normally run highest?
- April, on the long-term record. The median daily flow that month is about 4,272 cfs, against 309.5 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 San Joaquin River near Mendota, CA?
- It depends on the month. In February, half of days historically fall near 454.6 cfs, with the middle 80% of days between 82 and 6,620 cfs. The month-by-month table on this page gives the full range.
- How long has San Joaquin River near Mendota, CA been measured?
- Discharge records at USGS site 11254000 begin in 1939, about 87 years, covering roughly 7,775 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
- Where is San Joaquin River near Mendota, CA?
- The gauge sits at 36.8105, -120.37823, in California, in hydrologic subbasin 18040001, at an elevation of about 133 feet, draining roughly 3,940 square miles.
- Can I use San Joaquin River near Mendota, 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.
Other gauges in this subbasin
- San Joaquin River near Stevinson, CA
- Salt Slough A Hwy 165 near Stevinson, CA
- San Joaquin River A Fremont Ford Bridge, CA
- Mud Slough near Gustine, CA
- San Joaquin River Ab Merced River near Newman, CA
- San Joaquin River below Friant, CA
- San Joaquin River below Hwy 41 near Pinedale, CA
- San Joaquin River A Skaggs Br near Ripperdan, CA