Damming Yosemite Park's Hetch Hetchy Valley

In the least crowded corner of Yosemite National Park, debates about the future of Hetch Hetchy Valley have been going on for over 100 years.
By Staff ,

Overlooking Hetch Hetchy Valley with the O’Shaughnessy Dam and Wapama Falls. Photo by Gloria Wadzinski

In the least crowded corner of Yosemite National Park, debates about the future of Hetch Hetchy Valley have been going on for over 100 years.

When naturalist and conservationist John Muir first visited the valley, he wrote that is was "a grand landscape garden, one of Nature's rarest and most precious mountain temples." Even after Muir won the fight to preserve Yosemite as a national park in 1890, and later to expand that protection to the Sierra Nevada high country, in the end he couldn't save the Hetch Hetchy Valley.

In 1913, Congress authorized a public-works project to dam the Tuolumne River. Ten years later, construction of the O'Shaughnessy Dam was completed, completely flooding the Hetch Hetchy Valley. Today the valley floor still sits underwater, completely covered by a reservoir that supplies the growing urban population of the San Francisco Bay Area. Park visitors can walk atop the dam, and imagine what the valley once looked like.

The O’Shaughnessy Dam at Hetch Hetchy Valley. Photo by Gloria Wadzinski

Gloria Wadzinski

Some environmentalists including the Sierra Club have never given up Muir's fight to save Hetch Hetchy, and many still dream of returning the valley to its natural state. After much political wrangling, the issue went on the ballot for California voters to decide in late 2010 and was defeated.

But even if it is still too late to save Hetch Hetchy, what happened there did help turn the tide against damming rivers elsewhere in the West, including at Kings Canyon in the Sierra Nevada and the Grand Canyon in Arizona, where dams were never built.

Hetch Hetchy by the Numbers

1913

is the year president Woodrow Wilson signed the Raker Act, allowing San Francisco to Build a Dam in the Hetch Hetchy Valley.

1938

is the year the O'Shaughnessy Dam was completed.

3,900

feet is the area's elevation, making for a long hiking season.

2.4 million

San Francisco area residents rely on the dam for water.

38 miles

is how far it is from Yosemite Valley.

Source: National Park Service

Related stories:

Yosemite's Hetch Hetchy vs. California's Need for Water

Easy Hike to Wapama Falls in Hetch Hetchy Valley