Round the World Magazine

A Trip to Hetch Hetchy and the O’Shaughnessy Dam

Hetch Hetchy and the O’Shaughnessy Dam

We were driving through the north western part of Yosemite National Park when we stumbled on this…
Gateway to Hetch Hetchy park, California
The ‘Gateway to Hetch Hetchy’, and we wondered, where it would take us. So obviously, we entered into the unknown.



It turns out Hetch Hetchy is a reservoir held together by the enormous O’Shaughnessy Dam in the heart of California.

Who knew! We’re writing a post about our trip here becasuse it was an incredible experience away from the hustle and bustle and tourism of Yosemite National Park.


Hetch Hetchy and the O’Shaughnessy dam should not be overlooked while visiting Yosemite National Park, the scenery here is incredible and you’ll find quiet spots throughout the area to picnic and enjoy the moment away from tourists who flock in from San Francisco and Los Angeles.


The full Hetch Hetchy Project provides 80% of the water supply for 2.6 million people.



Hetch Hetchy Facts

Hetch Hetchy is the name of the glacial valley where the reservoir resides. Hetch Hetchy is the collective name for the whole water system.

The Hetch Hetchy reservoir is drained by the Tuolumne River and the entire area is known for its natural beauty, similar to its neighbor in the Yosemite Valley.

In 1923, as part of the Hetch Hetchy Project, the O’Shaughnessy Dam was built on the Tuolumne River with the purpose of building up the Hetch Hetchy Reservoir.

The Hetch Hetchy dam and reservoir are the centerpieces of the project, and since 1934, it began to deliver water 167 miles (269 km) west to San Francisco and its client municipalities in the greater San Francisco Bay Area.

The city of San Francisco pays a lease of around $30,000 per year for the use of Hetch Hetchy, which sits on federal land.

Approximately 265,000 acre·ft (327,000 dam3) of water is delivered each year, or 31,900,000 cu ft (900,000 m3) per day, to residents of San Francisco and San Mateo, Santa Clara, and Alameda Counties.

The journey the water takes is approximately 160 miles.

O’Shaughnessey Dam Facts

The O’Shaughnessy Dam and reservoir, and the series of aqueducts, tunnels, and tunnels as well as 8 other dams make up the entire Hetch Hetchy Project.


The O’Shaughnessy Dam is 430-foot (131 m) high made of concrete and it is named after engineer Michael O’Shaughnessy, who oversaw the entire construction.

The Dam may not have existed if it wasn’t for the disastrous earthquake and fire of 1906, which underscored the insufficiency of the existing water supply.

In 1890, the city of San Francisco was rapidly outgrowing its limited water supply, which depended on intermittent local springs and streams and San Francisco mayor James D. Phelan proposed to build a dam and aqueduct on the Tuolumne River which ultimately spawned the fixture of the O’Shaughnessy Dam.

The Journey through the Valley

A dual paved road takes you through the beautiful scenery of the Hetch Hetchy Valley, exactly like the roads through Yosemite National Park.

It’s easy to see where there was a lot of controversies when the Hetch Hetchy Project was implemented, the scenic views, beautiful flora and natural wonder is somewhat interrupted by the presence of the enormous Dam and hydro water.

The Hetchy Hetchy Valley was chosen for its water quality and hydroelectric potential, and it’s quite an experience finding it at the center of one of the most popular national parks in the system.

There are a few spots to pull over for incredible views when driving downhill to the Dam itself. H3 was a good spot for one of the best views we have ever encountered in California.

Seriously, where else can you get an unspoiled, peaceful view like this…

The drive to the O’Shaughnessy Dam is downhill, straightforward and peaceful. There is a campground by the dam and easy parking.

Exit your vehicle and walk across the dam for an experience you’ll never forget.


Enjoy the informative boards that tell you how and when the dam was built…


And how much renewable energy it brings to over 2 million people 160 miles away.


Venture through the dark tunnel at the end of the Dam head if you dare…

The tunnel leads to the Hetch Hetchy Trailhead where you can walk around the reservoir among beautiful cliffs and pine trees, just keep an eye out for black bears!

For More Information, Visit the Official Site.


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