Rivermatics

USGS Streamgage 11134000

Santa Ynez River A H St near Lompoc, CA

Santa Ynez River A H St near Lompoc, CA is USGS streamgage 11134000 in California, monitoring river discharge in hydrologic subbasin 18060010. It drains a watershed of about 815 square miles. Discharge records at this site go back to 1946. Typical flow runs near 0 cfs in July and 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.

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Gauge details

State
California
Drainage area
815 sq mi
Gauge elevation
61 ft
Subbasin (HUC-8)
18060010
Coordinates
34.66831, -120.4579
USGS site number
11134000
Records begin
1946-10-01 (80 years)
Rivermatics forecast
14-day flow outlook

Typical flow by month

Long-term daily discharge percentiles from the USGS record (up to 74 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 0 0.6 193.1
February 0 12.9 665.2
March 0 10 787.7
April 0 2 494.2
May 0 0 158.9
June 0 0 28.9
July 0 0 2.6
August 0 0 0.4
September 0 0 4.5
October 0 0 6.9
November 0 0 4.9
December 0 0 47.9

All values in cubic feet per second (cfs).

Common questions

When does Santa Ynez River A H St near Lompoc, CA normally run highest?
February, on the long-term record. The median daily flow that month is about 12.9 cfs, against 0 cfs in May, the lowest month. These are historical normals for the date, not a forecast and not today's reading.
What is a normal flow for Santa Ynez River A H St near Lompoc, CA?
It depends on the month. In January, half of days historically fall near 0.6 cfs, with the middle 80% of days between 0 and 193.1 cfs. The month-by-month table on this page gives the full range.
How long has Santa Ynez River A H St near Lompoc, CA been measured?
Discharge records at USGS site 11134000 begin in 1946, about 80 years, covering roughly 9,129 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
Is there a flow forecast for Santa Ynez River A H St near Lompoc, 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 Santa Ynez River A H St near Lompoc, CA?
The gauge sits at 34.66831, -120.4579, in California, in hydrologic subbasin 18060010, at an elevation of about 61 feet, draining roughly 815 square miles.
Can I use Santa Ynez River A H St near Lompoc, 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.

Other gauges in this subbasin