Tuolumne R A Grand Cyn of Tuolumne AB Hetch Hetchy Water Level
Live river level, flow, historical records and forecast for Tuolumne R A Grand Cyn of Tuolumne AB Hetch Hetchy in CA, United States, built from official government gauge data.
- Location CA, United States
- Watershed upper tuolumne
- Primary gauge 11274790 (USGS)
About Tuolumne R A Grand Cyn of Tuolumne AB Hetch Hetchy
The watershed
The Tuolumne River at Grand Canyon of Tuolumne above Hetch Hetchy sits in the Upper Tuolumne watershed in California.
The station drains 301 square miles (780 km2) upstream of this point, so the reading here reflects what is happening in that upstream basin, not the watershed as a whole. For people downstream, that means the gauge is best read as a local check on how much water is moving through this reach, not as a summary of every tributary in the larger system.
In this part of California, the seasonal pattern matters. High water usually comes in spring and early summer, then summer and early fall tend to fall away. On this station, the highest typical month is May at 12.41 ft (3.78 m), while the lowest typical month is October at 6.9 ft (2.1 m). The usual annual swing is 5.5 ft (1.68 m), which is the range a dock, bank setup, or intake has to be ready to handle.
What the numbers say
The record high is 18.68 ft (5.69 m) in June 2010. The record low is 6.47 ft (1.97 m) in November 2020. Those two marks show that this site can move from low-water conditions to a much fuller channel over the course of a year.
For anyone fishing this water, the gap between the typical low month and the record low is worth watching because shallow margins and access points can change quickly. For anyone with a dock or intake, the seasonal swing is the more practical number than a single day’s reading, because it shows the band of levels this station has already seen in its record.
There are 20 years on record here, so these values are enough to show the shape of the station, even if they do not tell every detail of every season.
Reading the hero number
The hero number on this page is best read against the median for the same calendar day, not against raw elevation. A river level can be higher or lower depending on the time of year, so the calendar-day median tells you whether today is ordinary for this date, above it, or below it.
This station is published by the U.S. Geological Survey, and the record spans about 20 years. That makes the day-to-day comparison more useful than a single standing level: it gives you context for whether the river is running near its usual range for this date, which is what matters for access, bank conditions, and local decisions.
How this page is built
Readings come from official government gauges and are rolled into daily records: the daily mean, high and low for every day on record. Each calendar day gets its own baseline from the full history, so the level you see is compared against what this specific date usually looks like rather than an annual average.
How Nibi Metrics works · Water stories
Nibi Metrics - live water levels, flow, and forecasts for lakes and rivers across Canada, the US and the UK
Real-time water levels, forecasts, and alerts for lakes and rivers across Canada, the US and the UK. Built on official government data.
Nibi Metrics tracks more than 13,000 gauged lakes and rivers across Canada, the United States and the United Kingdom, reading directly from official federal monitoring networks: the Water Survey of Canada, the United States Geological Survey, Quebec's provincial hydrometric network, and the Environment Agency for England. Every number on the platform is measured, not modelled - taken from a government gauge on the water itself and compared against that location's own historical record for this exact date.
What you can see for any monitored lake or river
The level right now, in feet or metres, updated as the source agency publishes new readings - for many stations that is every five to fifteen minutes. How today compares to typical: every location carries its own typical-for-this-date band built from its historical record, so a reading is never just a number - it is above, below, or near what this water usually does on this calendar day. Which way it is moving: a measured RISING, FALLING, or STEADY verdict computed from the gauge's own recent readings, with the rate of change - the difference between a flood ending and one beginning. What comes next: level forecasts up to 72 hours ahead, driven by the gauge's recent behaviour, upstream water, and quantitative precipitation forecasts, alongside live radar, lightning, and weather for the surrounding region.
Alerts that watch the water for you
Set a threshold on any location - a level, a distance above typical, or a rate of climb - and Nibi emails or notifies you the moment the gauge crosses it. Cottagers use it for spring freshet, anglers for river conditions, marinas and municipalities for operations. The scanning runs around the clock against the same measured data shown on every page.
Where Nibi comes from
Nibi means water in Anishinaabemowin. The platform began at a family cottage on Lake Muskoka, Ontario, where the spring melt floods the shoreline most years and the only forecast was standing on the dock, looking, and guessing. It grew into an independent, member-funded platform run by Muskoka Research Inc. - no investors, no data resale, and a privacy policy shorter than most cookie banners. The core data is free for everyone, forever; paid plans add automation like multi-location alerts, deep history, and reports.
Coverage
Nibi spans the continent: every Canadian province and territory with active federal gauges - from Vancouver Island rivers to the Muskoka lakes, prairie reservoirs, and Quebec's hydrometric network - and the United States from Maine to the Texas Hill Country, the Ohio Valley, and the Pacific Northwest. Coverage grows where the water news is: when a basin floods, its gauges join the platform with their full historical records attached. Many stations report every five to fifteen minutes; most report at least hourly; every page states exactly when its gauge last spoke.
Free forever, funded by members
The core promise is simple: the water data is free, for everyone, forever. Live levels, maps, radar, and recent history never sit behind a paywall. Paid plans fund the platform by adding automation - multi-location alerts, decades of history, longer forecasts, and PDF reports - so the people who need more carry the cost for everyone who just needs to check the lake before driving up. There are no investors and no advertising deals shaping what the data says.
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How every number is computed - About the platform
