USGS Streamgage 11042000
San Luis Rey River A Oceanside, CA
San Luis Rey River A Oceanside, CA is USGS streamgage 11042000 in California, monitoring river discharge in hydrologic subbasin 18070303. It drains a watershed of about 557 square miles. Discharge records at this site go back to 1912. Typical flow runs near 0.4 cfs in July and 14.2 cfs in April, with the higher of the two arriving in April.
Gauge details
- State
- California
- Drainage area
- 557 sq mi
- Gauge elevation
- 9 ft
- Subbasin (HUC-8)
- 18070303
- Coordinates
- 33.21809, -117.3603
- USGS site number
- 11042000
- Records begin
- 1912-10-01 (114 years)
Typical flow by month
Long-term daily discharge percentiles from the USGS record (up to 97 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 | 7.9 | 101.4 | |
| February | 0 | 20.4 | 165 | |
| March | 0 | 24.5 | 253.8 | |
| April | 0 | 14.2 | 133 | |
| May | 0 | 6 | 59.8 | |
| June | 0 | 2.6 | 23.2 | |
| July | 0 | 0.4 | 10.2 | |
| August | 0 | 0 | 6.9 | |
| September | 0 | 0 | 6.1 | |
| October | 0 | 0 | 8.2 | |
| November | 0 | 0 | 20.4 | |
| December | 0 | 2.1 | 46.1 |
All values in cubic feet per second (cfs).
Common questions
- When does San Luis Rey River A Oceanside, CA normally run highest?
- March, on the long-term record. The median daily flow that month is about 24.5 cfs, against 0 cfs in August, 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 Luis Rey River A Oceanside, CA?
- It depends on the month. In January, half of days historically fall near 7.9 cfs, with the middle 80% of days between 0 and 101.4 cfs. The month-by-month table on this page gives the full range.
- How long has San Luis Rey River A Oceanside, CA been measured?
- Discharge records at USGS site 11042000 begin in 1912, about 114 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 Luis Rey River A Oceanside, CA?
- The gauge sits at 33.21809, -117.3603, in California, in hydrologic subbasin 18070303, at an elevation of about 9 feet, draining roughly 557 square miles.
- Can I use San Luis Rey River A Oceanside, 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.