USGS Streamgage 11162735
San Mateo C Ab Junction Box A Dam1 near Hillsborough
San Mateo C Ab Junction Box A Dam1 near Hillsborough is USGS streamgage 11162735 in California, monitoring river discharge in hydrologic subbasin 18050004. It drains a watershed of about 2 square miles. Discharge records at this site go back to 2022. Typical flow runs near 0 cfs in July and 1.8 cfs in April, with the higher of the two arriving in April.
Gauge details
- State
- California
- Drainage area
- 2 sq mi
- Gauge elevation
- 648 ft
- Subbasin (HUC-8)
- 18050004
- Coordinates
- 37.55697, -122.41825
- USGS site number
- 11162735
- Records begin
- 2022-02-23 (4 years)
Typical flow by month
Long-term daily discharge percentiles from the USGS record (up to 5 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 | — | 7.3 | — | |
| February | — | 7.6 | — | |
| March | — | 3 | — | |
| April | — | 1.8 | — | |
| May | — | 0.5 | — | |
| June | — | 0.1 | — | |
| July | — | 0 | — | |
| August | — | 0 | — | |
| September | — | 0 | — | |
| October | — | 0 | — | |
| November | — | 0 | — | |
| December | — | 2.2 | — |
All values in cubic feet per second (cfs).
Common questions
- When does San Mateo C Ab Junction Box A Dam1 near Hillsborough normally run highest?
- February, on the long-term record. The median daily flow that month is about 7.6 cfs, against 0 cfs in July, the lowest month. These are historical normals for the date, not a forecast and not today's reading.
- How long has San Mateo C Ab Junction Box A Dam1 near Hillsborough been measured?
- Discharge records at USGS site 11162735 begin in 2022, about 4 years, covering roughly 1,620 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
- Where is San Mateo C Ab Junction Box A Dam1 near Hillsborough?
- The gauge sits at 37.55697, -122.41825, in California, in hydrologic subbasin 18050004, at an elevation of about 648 feet, draining roughly 2 square miles.
- Can I use San Mateo C Ab Junction Box A Dam1 near Hillsborough 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 Mateo C below Junction Box A Dam1 near Hillsborough
- San Mateo C below Lo Crystal Sp Reservoir near San Mateo, CA
- Alameda C Ab Diversion Dam near Sunol, CA
- Alameda C below Diversion Dam near Sunol, CA
- Arroyo Hondo near San Jose, CA
- Calaveras C near Sunol, CA
- Alameda C below Calaveras C near Sunol, CA
- Alameda C below Welch C near Sunol, CA