Rivermatics

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. 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
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)
Rivermatics forecast
14-day flow outlook

14-day flow forecast

Based on observations through for San Mateo C Ab Junction Box A Dam1 near Hillsborough. 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.

Forecast daily mean discharge in cubic feet per second, by date
Date Low p10 Expected p50 High p90 Range
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0

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 5 years of data), averaged within each month. These describe the historical normal range — they are not a forecast and not today's reading.

Historical monthly discharge percentiles in cubic feet per second
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 1,624 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
Is there a flow forecast for San Mateo C Ab Junction Box A Dam1 near Hillsborough?
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 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