USGS Streamgage 11153650
Llagas C near Gilroy
Llagas C near Gilroy is USGS streamgage 11153650 in California, monitoring river discharge in hydrologic subbasin 18060002. It drains a watershed of about 84 square miles. Discharge records at this site go back to 2002. Typical flow runs near 2.9 cfs in July and 11.1 cfs in April, with the higher of the two arriving in April.
Gauge details
- State
- California
- Drainage area
- 84 sq mi
- Gauge elevation
- 146 ft
- Subbasin (HUC-8)
- 18060002
- Coordinates
- 36.98741, -121.52712
- USGS site number
- 11153650
- Records begin
- 2002-11-23 (24 years)
Typical flow by month
Long-term daily discharge percentiles from the USGS record (up to 24 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 | 1 | 7.7 | 218.9 | |
| February | 2.6 | 10.1 | 199.4 | |
| March | 3.1 | 12.6 | 163.5 | |
| April | 2.6 | 11.1 | 71 | |
| May | 1.9 | 8 | 23.7 | |
| June | 1 | 5.2 | 12.3 | |
| July | 0.1 | 2.9 | 6.4 | |
| August | 0 | 1.8 | 4.6 | |
| September | 0 | 0.8 | 3.7 | |
| October | 0 | 1.1 | 4.3 | |
| November | 0 | 1.9 | 5.8 | |
| December | 0.4 | 4 | 33.2 |
All values in cubic feet per second (cfs).
Common questions
- When does Llagas C near Gilroy normally run highest?
- March, on the long-term record. The median daily flow that month is about 12.6 cfs, against 0.8 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 Llagas C near Gilroy?
- It depends on the month. In January, half of days historically fall near 7.7 cfs, with the middle 80% of days between 1 and 218.9 cfs. The month-by-month table on this page gives the full range.
- How long has Llagas C near Gilroy been measured?
- Discharge records at USGS site 11153650 begin in 2002, about 24 years, covering roughly 8,614 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
- Where is Llagas C near Gilroy?
- The gauge sits at 36.98741, -121.52712, in California, in hydrologic subbasin 18060002, at an elevation of about 146 feet, draining roughly 84 square miles.
- Can I use Llagas C near Gilroy 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.