The Lost Twin of Yosemite Valley That Even John Muir Couldn’t Save From Being Flooded

Hetch Hetchy Valley (Yosemite)

John Muir called Hetch Hetchy Valley “Yosemite’s twin.” Then San Francisco showed up with dynamite and concrete mixers. What followed was a decade-long brawl that split the nation and changed how we think about nature forever.

Here’s the wild story, plus how to explore this controversial valley that’s still making waves.

San Francisco’s Desperate Water Search

San Francisco struggled with poor water supplies throughout the late 1800s. The growing city depended on small local springs and streams that couldn’t meet its needs.

City engineer Carl Grunsky looked at possible water sources in 1900-1901 and picked the Tuolumne River flowing through Hetch Hetchy as the best option.

Mayor James Phelan got water rights to the Tuolumne in 1901, but federal officials first said no to damming the valley. Everything changed on April 18, 1906, when a massive earthquake hit.

The quake and resulting fire wiped out 25,000 buildings across 490 city blocks. Water pipes broke, leaving firefighters helpless as flames ate through the city.

People blamed the Spring Valley Water Company, which controlled all the city’s water. Determined to prevent another disaster, city leaders pushed harder for the Hetch Hetchy dam.

The Birth of Environmental Activism

The Hetch Hetchy fight started America’s first major environmental battle. For the first time, people across the country argued about how public lands should be used.

Two main ideas emerged. Preservationists thought certain natural places should stay untouched because of their beauty and spiritual value. Conservationists believed natural resources should be used carefully to help society.

The Sierra Club, started by John Muir in 1892, led the fight against the dam. First created to protect the Sierra Nevada mountains, the club now faced its biggest challenge.

Americans from all walks of life joined the debate. City water needs clashed with national concerns about protecting parklands.

John Muir’s Passionate Defense

John Muir launched a fierce nationwide campaign against the dam starting in 1908. The Scottish-born nature lover had spent decades exploring and writing about California’s Sierra Nevada mountains.

Muir wrote extensively about Hetch Hetchy, including moving essays and his 1912 book “The Yosemite.” His powerful words inspired 200 newspaper editorials across the country to oppose the dam.

Knowing public opinion mattered, the Sierra Club held a formal vote on the issue. Muir wrote the case against it in a pamphlet called “The Hetch Hetchy Valley,” arguing the dam would ruin a national treasure.

“Landscape gardens, places of recreation and worship, are never made beautiful by destroying and burying them,” he wrote, rejecting claims that a lake would make the valley more attractive.

Muir’s work showed a new way of thinking about nature—protecting it for its own sake rather than just for what humans could get from it.

Gifford Pinchot’s Utilitarian Vision

Gifford Pinchot, America’s first Chief Forester, became the main voice supporting the dam.

When speaking to Congress in 1913, Pinchot argued that giving clean water to half a million San Franciscans outweighed saving the valley for the few thousand tourists who visited each year.

Ironically, Muir and Pinchot had once been friends, camping together in Montana’s wilderness before the Hetch Hetchy issue split them apart.

The Congressional Battle

San Francisco officially applied for Hetch Hetchy water rights in 1908 under Mayor Edward Robeson Taylor. For five years, Congress debated whether a city should be allowed to dam a national park.

The Raker Act, named for Congressman John Raker of California, finally passed on December 7, 1913. The bill allowed flooding the valley to create a city water supply.

President Woodrow Wilson, facing heavy pressure from both sides, signed the bill into law on December 19, 1913.

Building the O’Shaughnessy Dam

Work began in 1914 on what would become one of America’s biggest engineering projects of the early 1900s.

City Engineer Michael O’Shaughnessy led the huge project that would later carry his name. Workers first dug more than 100 feet into the riverbed to reach solid granite bedrock, creating a stable base for the dam.

Crews cut down centuries-old trees from the valley floor to prepare for flooding. Concrete plants ran on-site, mixing local sand and rock with cement brought in by rail.

When finished in 1923, the first dam stood 227 feet high. Engineers raised it to its current height of 312 feet in 1938, creating a lake holding billions of gallons of water.

John Muir’s Final Battle

The Hetch Hetchy controversy became John Muir’s last and most crushing conservation battle. At 76 years old, he had given decades to protecting America’s wild places.

The defeat hit Muir hard. After Congress approved the dam, he wrote to a friend that he felt like he was “going into battle already wounded.” His health quickly got worse in the months that followed.

Muir died of pneumonia in a Los Angeles hospital on December 24, 1914, just one year after losing the Hetch Hetchy fight.

Some writers suggest the loss helped break his health, noting that “the prophet didn’t make enough conversions” to save the valley he loved.

The Birth of the National Park Service

Public anger over flooding Hetch Hetchy Valley sparked a movement to prevent similar losses in other national parks.

Just three years after the Raker Act, Congress passed the National Park Service Act in 1916.

No similar damage has been allowed in any national park since Hetch Hetchy.

The Hetch Hetchy Water System Today

The Hetch Hetchy water system now delivers clean Sierra Nevada water to 2.7 million people throughout the San Francisco Bay Area.

The reservoir can hold up to 117 billion gallons of water, supplying San Francisco, Santa Clara, Alameda, and San Mateo counties.

Snowmelt from the high Sierra Nevada mountains creates water so pure that it rarely needs filtering. The system has received a filtration exemption from federal authorities, one of the few large city water supplies in the nation clean enough to qualify for this special status.

Hetch Hetchy water also powers hydroelectric generators along its route, creating clean electricity for public buildings, streetlights, and transit systems in San Francisco.

Visiting Hetch Hetchy

Hetch Hetchy sits in the northwest corner of Yosemite National Park, reached via Evergreen Road near the town of Groveland. Unlike Yosemite Valley with its millions of yearly visitors, this remote area sees only about 44,000 visitors each year.

Visitors can walk across O’Shaughnessy Dam for views of the 312-foot concrete structure and the water-filled valley beyond.

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