USGS Streamgage 11101250
Rio Hondo Ab Whittier Narrows Dam, CA
Rio Hondo Ab Whittier Narrows Dam, CA is USGS streamgage 11101250 in California, monitoring river discharge in hydrologic subbasin 18070105. It sits on the Rio Hondo, alongside 1 other gauge Rivermatics tracks on the same river. It drains a watershed of about 91 square miles. Discharge records at this site go back to 1956. Typical flow runs near 1.6 cfs in July and 1.8 cfs in April, with the higher of the two arriving in April. Rivermatics issues a daily machine-learned flow outlook for this gauge, reaching 14 days ahead.
View live conditions & forecast →
Gauge details
- State
- California
- Drainage area
- 91 sq mi
- Gauge elevation
- 220 ft
- Subbasin (HUC-8)
- 18070105
- Coordinates
- 34.05834, -118.07173
- USGS site number
- 11101250
- Records begin
- 1956-03-01 (70 years)
- Rivermatics forecast
- 14-day flow outlook
14-day flow forecast
Based on observations through for Rio Hondo Ab Whittier Narrows Dam, CA. Each day carries a median estimate and the band the model expects the flow to fall within — not a single number to plan against. Forecasts are re-issued daily; see the live screen for the current outlook.
| Date | Low p10 | Expected p50 | High p90 | Range |
|---|---|---|---|---|
| 2.1 | 2.4 | 2.8 | ||
| 2 | 2.4 | 2.8 | ||
| 1.8 | 2.3 | 2.9 | ||
| 1.8 | 2.3 | 3.1 | ||
| 1.7 | 2.3 | 3.2 | ||
| 1.7 | 2.3 | 3 | ||
| 1.5 | 2.2 | 3.3 | ||
| 1.5 | 2.2 | 3.2 | ||
| 1.7 | 2.7 | 7.1 | ||
| 1.8 | 4.3 | 32.1 | ||
| 1.6 | 2.6 | 6.4 | ||
| 1.5 | 2.3 | 3.6 | ||
| 1.4 | 2.2 | 3.5 | ||
| 1.3 | 2.3 | 3.6 |
All values in cubic feet per second (cfs). Estimates only — do not use them for navigation or for any safety, rescue, or emergency decision.
Typical flow by month
Long-term daily discharge percentiles from the USGS record (up to 71 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 | 0.3 | 1.6 | 182.9 | |
| February | 0.4 | 2.1 | 427.8 | |
| March | 0.4 | 2.2 | 245.5 | |
| April | 0.4 | 1.8 | 151.2 | |
| May | 0.3 | 1.3 | 107.1 | |
| June | 0.4 | 1.5 | 120.9 | |
| July | 0.4 | 1.6 | 38.7 | |
| August | 0.3 | 1.5 | 12.2 | |
| September | 0.4 | 1.5 | 20.1 | |
| October | 0.3 | 1.4 | 25.4 | |
| November | 0.3 | 1.2 | 92 | |
| December | 0.3 | 1.4 | 118.7 |
All values in cubic feet per second (cfs).
Common questions
- When does Rio Hondo Ab Whittier Narrows Dam, CA normally run highest?
- March, on the long-term record. The median daily flow that month is about 2.2 cfs, against 1.2 cfs in November, 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 Ab Whittier Narrows Dam, CA?
- It depends on the month. In January, half of days historically fall near 1.6 cfs, with the middle 80% of days between 0.3 and 182.9 cfs. The month-by-month table on this page gives the full range.
- How long has Rio Hondo Ab Whittier Narrows Dam, CA been measured?
- Discharge records at USGS site 11101250 begin in 1956, about 70 years, covering roughly 9,130 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
- Is there a flow forecast for Rio Hondo Ab Whittier Narrows Dam, CA?
- Yes. Rivermatics trains a machine-learned model — a temporal-fusion transformer — on this basin's observed flows, weather, and snowpack, and issues a daily flow outlook reaching 14 days ahead: a median estimate inside a confidence band, not a single number to bet on. Every forecast is scored against days the model never trained on, and that track record is published on the live gauge screen. Open live conditions to see the current outlook.
- Where is Rio Hondo Ab Whittier Narrows Dam, CA?
- The gauge sits at 34.05834, -118.07173, in California, in hydrologic subbasin 18070105, at an elevation of about 220 feet, draining roughly 91 square miles.
- Can I use Rio Hondo Ab 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.
Upstream and downstream on the Rio Hondo
Every gauge Rivermatics tracks on this river, ordered by drainage area — upstream first. See the Rio Hondo in full.
- Rio Hondo Ab Whittier Narrows Dam, CA this page
- Rio Hondo below Whittier Narrows Dam, CA 124 sq mi