USGS Streamgage 11172955
Alameda C below Diversion Dam near Sunol, CA
Alameda C below Diversion Dam near Sunol, CA is USGS streamgage 11172955 in California, monitoring river discharge in hydrologic subbasin 18050004. It sits on the Alameda C, alongside 5 other gauges Rivermatics tracks on the same river. It drains a watershed of about 35 square miles. Discharge records at this site go back to 2010. Typical flow runs near 0.4 cfs in July and 12.2 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
- 35 sq mi
- Gauge elevation
- 836 ft
- Subbasin (HUC-8)
- 18050004
- Coordinates
- 37.49861, -121.77944
- USGS site number
- 11172955
- Records begin
- 2010-10-01 (16 years)
- Rivermatics forecast
- 14-day flow outlook
14-day flow forecast
Based on observations through for Alameda C below Diversion Dam near Sunol, 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 |
|---|---|---|---|---|
| 0.1 | 0.1 | 0.1 | ||
| 0.1 | 0.1 | 0.1 | ||
| 0.1 | 0.1 | 0.1 | ||
| 0.1 | 0.1 | 0.1 | ||
| 0.1 | 0.1 | 0.1 | ||
| 0.1 | 0.1 | 0.1 | ||
| 0.1 | 0.1 | 0.1 | ||
| 0.1 | 0.1 | 0.1 | ||
| 0.1 | 0.1 | 0.1 | ||
| 0.1 | 0.1 | 0.1 | ||
| 0.1 | 0.1 | 0.1 | ||
| 0.1 | 0.1 | 0.1 | ||
| 0.1 | 0.1 | 0.1 | ||
| 0.1 | 0.1 | 0.1 |
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 16 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 | 0.1 | 4.6 | 293.6 | |
| February | 0.4 | 4.1 | 293.2 | |
| March | 0.9 | 13.6 | 232 | |
| April | 1 | 12.2 | 45.1 | |
| May | 0.5 | 3.3 | 12.2 | |
| June | 0.2 | 1.5 | 4.4 | |
| July | 0 | 0.4 | 1.6 | |
| August | 0 | 0.1 | 0.6 | |
| September | 0 | 0 | 0.3 | |
| October | 0 | 0.1 | 2.5 | |
| November | 0 | 0.2 | 2.6 | |
| December | 0.1 | 2.4 | 152.9 |
All values in cubic feet per second (cfs).
Common questions
- When does Alameda C below Diversion Dam near Sunol, CA normally run highest?
- March, on the long-term record. The median daily flow that month is about 13.6 cfs, against 0 cfs in September, the lowest month. These are historical normals for the date, not a forecast and not today's reading.
- What is a normal flow for Alameda C below Diversion Dam near Sunol, CA?
- It depends on the month. In January, half of days historically fall near 4.6 cfs, with the middle 80% of days between 0.1 and 293.6 cfs. The month-by-month table on this page gives the full range.
- How long has Alameda C below Diversion Dam near Sunol, CA been measured?
- Discharge records at USGS site 11172955 begin in 2010, about 16 years, covering roughly 5,788 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
- Is there a flow forecast for Alameda C below Diversion Dam near Sunol, 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 Alameda C below Diversion Dam near Sunol, CA?
- The gauge sits at 37.49861, -121.77944, in California, in hydrologic subbasin 18050004, at an elevation of about 836 feet, draining roughly 35 square miles.
- Can I use Alameda C below Diversion Dam near Sunol, 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 Alameda C
Every gauge Rivermatics tracks on this river, ordered by drainage area — upstream first. See the Alameda C in full.
- Alameda C Ab Diversion Dam near Sunol, CA 33 sq mi
- Alameda C below Diversion Dam near Sunol, CA this page
- Alameda C below Calaveras C near Sunol, CA 139 sq mi
- Alameda C below Welch C near Sunol, CA 149 sq mi
- Alameda C near Niles, CA 633 sq mi
- Alameda C near Fremont, CA 638 sq mi