Rivermatics

USGS Streamgage 11276500

Tuolumne River near Hetch Hetchy, CA

Tuolumne River near Hetch Hetchy, CA is USGS streamgage 11276500 in California, monitoring river discharge in hydrologic subbasin 18040009. It sits on the Tuolumne River, alongside 3 other gauges Rivermatics tracks on the same river. It drains a watershed of about 457 square miles. Discharge records at this site go back to 1910. Typical flow runs near 133.8 cfs in July and 112 cfs in April, with the higher of the two arriving in July. 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
457 sq mi
Gauge elevation
3,452 ft
Subbasin (HUC-8)
18040009
Coordinates
37.93741, -119.7982
USGS site number
11276500
Records begin
1910-10-01 (116 years)
Rivermatics forecast
14-day flow outlook

14-day flow forecast

Based on observations through for Tuolumne River near Hetch Hetchy, 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.

Forecast daily mean discharge in cubic feet per second, by date
Date Low p10 Expected p50 High p90 Range
58.4 67.7 72.3
54.3 66.7 73.1
51.2 65 73.2
48.4 63.9 73.7
46.7 63.3 74.1
45.3 62.8 74.4
44.3 62.4 74.5
43.5 62.1 74.6
43.9 62.2 75.1
43.7 62.3 75.6
42.8 62.6 76.6
43.6 62.8 76.9
42.4 62.2 75.9
42.1 61.9 75.8

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 59 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 35.6 47.8 102
February 34.6 57.9 135
March 34.7 55.6 184
April 35 112 922.3
May 53.6 390.7 4,020.3
June 75 771.7 4,907.7
July 73.7 133.8 2,611.5
August 75 119.1 201.5
September 54.4 78.1 105.7
October 35.1 51.7 67.7
November 34.8 52.5 66.3
December 35 45.6 64.2

All values in cubic feet per second (cfs).

Common questions

When does Tuolumne River near Hetch Hetchy, CA normally run highest?
June, on the long-term record. The median daily flow that month is about 771.7 cfs, against 45.6 cfs in December, the lowest month. These are historical normals for the date, not a forecast and not today's reading.
What is a normal flow for Tuolumne River near Hetch Hetchy, CA?
It depends on the month. In January, half of days historically fall near 47.8 cfs, with the middle 80% of days between 35.6 and 102 cfs. The month-by-month table on this page gives the full range.
How long has Tuolumne River near Hetch Hetchy, CA been measured?
Discharge records at USGS site 11276500 begin in 1910, about 116 years, covering roughly 9,130 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
Is there a flow forecast for Tuolumne River near Hetch Hetchy, 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 Tuolumne River near Hetch Hetchy, CA?
The gauge sits at 37.93741, -119.7982, in California, in hydrologic subbasin 18040009, at an elevation of about 3,452 feet, draining roughly 457 square miles.
Can I use Tuolumne River near Hetch Hetchy, 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 Tuolumne River

Every gauge Rivermatics tracks on this river, ordered by drainage area — upstream first. See the Tuolumne River in full.

Other gauges in this subbasin