USGS Streamgage 11274790
Tuolumne River A Grand Cyn of Tuolumne Ab Hetch Hetchy
Tuolumne River A Grand Cyn of Tuolumne Ab Hetch Hetchy is USGS streamgage 11274790 in California, monitoring river discharge in hydrologic subbasin 18040009. It drains a watershed of about 301 square miles. Discharge records at this site go back to 2006. Typical flow runs near 213.9 cfs in July and 786.7 cfs in April, with the higher of the two arriving in April.
Gauge details
- State
- California
- Drainage area
- 301 sq mi
- Gauge elevation
- 3,814 ft
- Subbasin (HUC-8)
- 18040009
- Coordinates
- 37.91658, -119.65986
- USGS site number
- 11274790
- Records begin
- 2006-10-13 (20 years)
Typical flow by month
Long-term daily discharge percentiles from the USGS record (up to 20 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 | 19.1 | 107.8 | 394.7 | |
| February | 66.4 | 180.1 | 453.5 | |
| March | 140.6 | 293.5 | 627.3 | |
| April | 405.3 | 786.7 | 1,541.6 | |
| May | 811.8 | 1,454.5 | 3,104.8 | |
| June | 363.4 | 930.4 | 4,440 | |
| July | 80.3 | 213.9 | 2,123.2 | |
| August | 26.2 | 54.6 | 453.1 | |
| September | 9 | 19.1 | 149.4 | |
| October | 6.5 | 15.3 | 367.1 | |
| November | 9.2 | 38.3 | 306.5 | |
| December | 14.8 | 68 | 359.5 |
All values in cubic feet per second (cfs).
Common questions
- When does Tuolumne River A Grand Cyn of Tuolumne Ab Hetch Hetchy normally run highest?
- May, on the long-term record. The median daily flow that month is about 1,454.5 cfs, against 15.3 cfs in October, 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 A Grand Cyn of Tuolumne Ab Hetch Hetchy?
- It depends on the month. In January, half of days historically fall near 107.8 cfs, with the middle 80% of days between 19.1 and 394.7 cfs. The month-by-month table on this page gives the full range.
- How long has Tuolumne River A Grand Cyn of Tuolumne Ab Hetch Hetchy been measured?
- Discharge records at USGS site 11274790 begin in 2006, about 20 years, covering roughly 7,099 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
- Where is Tuolumne River A Grand Cyn of Tuolumne Ab Hetch Hetchy?
- The gauge sits at 37.91658, -119.65986, in California, in hydrologic subbasin 18040009, at an elevation of about 3,814 feet, draining roughly 301 square miles.
- Can I use Tuolumne River A Grand Cyn of Tuolumne Ab Hetch Hetchy 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
- Tuolumne River near Hetch Hetchy, CA
- Tuolumne River Ab Early Intake near Mather, CA
- Tuolumne River below Early Intake near Mather, CA
- Cherry C below Valley Dam near Hetch Hetchy, CA
- Eleanor C near Hetch Hetchy, CA
- Cherry C near Early Intake, CA
- Cherry C below Dion River Holm Ph near Mather, CA
- Big C Ab Whites Gulch near Groveland, CA