USGS Streamgage 11149900
San Antonio River near Lockwood, CA
San Antonio River near Lockwood, CA is USGS streamgage 11149900 in California, monitoring river discharge in hydrologic subbasin 18060005. It drains a watershed of about 217 square miles. Discharge records at this site go back to 1965. Typical flow runs near 0 cfs in July and 58.8 cfs in April, with the higher of the two arriving in April.
Gauge details
- State
- California
- Drainage area
- 217 sq mi
- Gauge elevation
- 798 ft
- Subbasin (HUC-8)
- 18060005
- Coordinates
- 35.89663, -121.08825
- USGS site number
- 11149900
- Records begin
- 1965-10-01 (61 years)
Typical flow by month
Long-term daily discharge percentiles from the USGS record (up to 61 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 | 0.8 | 59.2 | 779.6 | |
| February | 13.6 | 81.1 | 1,060.9 | |
| March | 16.2 | 115.9 | 745 | |
| April | 7.9 | 58.8 | 287.8 | |
| May | 1.4 | 20.2 | 104.6 | |
| June | 0 | 3 | 41.7 | |
| July | 0 | 0 | 9.8 | |
| August | 0 | 0 | 0.1 | |
| September | 0 | 0 | 0 | |
| October | 0 | 0 | 0 | |
| November | 0 | 0 | 21.2 | |
| December | 0 | 9.5 | 209.3 |
All values in cubic feet per second (cfs).
Common questions
- When does San Antonio River near Lockwood, CA normally run highest?
- March, on the long-term record. The median daily flow that month is about 115.9 cfs, against 0 cfs in July, 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 Antonio River near Lockwood, CA?
- It depends on the month. In January, half of days historically fall near 59.2 cfs, with the middle 80% of days between 0.8 and 779.6 cfs. The month-by-month table on this page gives the full range.
- How long has San Antonio River near Lockwood, CA been measured?
- Discharge records at USGS site 11149900 begin in 1965, about 61 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 San Antonio River near Lockwood, CA?
- The gauge sits at 35.89663, -121.08825, in California, in hydrologic subbasin 18060005, at an elevation of about 798 feet, draining roughly 217 square miles.
- Can I use San Antonio River near Lockwood, 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.