USGS Streamgage 11102300
Rio Hondo below Whittier Narrows Dam, CA
Rio Hondo below Whittier Narrows Dam, CA is USGS streamgage 11102300 in California, monitoring river discharge in hydrologic subbasin 18070105. It drains a watershed of about 124 square miles. Discharge records at this site go back to 1966. Typical flow runs near 19 cfs in July and 61.9 cfs in April, with the higher of the two arriving in April.
Gauge details
- State
- California
- Drainage area
- 124 sq mi
- Gauge elevation
- 177 ft
- Subbasin (HUC-8)
- 18070105
- Coordinates
- 34.01668, -118.0884
- USGS site number
- 11102300
- Records begin
- 1966-10-01 (60 years)
Typical flow by month
Long-term daily discharge percentiles from the USGS record (up to 59 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 | 64.2 | 486.4 | |
| February | 0 | 76.9 | 799 | |
| March | 0.1 | 84.6 | 495.9 | |
| April | 0 | 61.9 | 237.5 | |
| May | 0 | 39.5 | 213.5 | |
| June | 0 | 38.2 | 197.5 | |
| July | 0 | 19 | 150.6 | |
| August | 0 | 6.1 | 136.7 | |
| September | 0 | 7.9 | 162 | |
| October | 0 | 16.8 | 215.1 | |
| November | 0 | 40.3 | 269.9 | |
| December | 0 | 61.9 | 301.3 |
All values in cubic feet per second (cfs).
Common questions
- When does Rio Hondo below Whittier Narrows Dam, CA normally run highest?
- March, on the long-term record. The median daily flow that month is about 84.6 cfs, against 6.1 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 Rio Hondo below Whittier Narrows Dam, CA?
- It depends on the month. In January, half of days historically fall near 64.2 cfs, with the middle 80% of days between 0 and 486.4 cfs. The month-by-month table on this page gives the full range.
- How long has Rio Hondo below Whittier Narrows Dam, CA been measured?
- Discharge records at USGS site 11102300 begin in 1966, about 60 years, covering roughly 9,103 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
- Where is Rio Hondo below Whittier Narrows Dam, CA?
- The gauge sits at 34.01668, -118.0884, in California, in hydrologic subbasin 18070105, at an elevation of about 177 feet, draining roughly 124 square miles.
- Can I use Rio Hondo below Whittier Narrows Dam, 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.