Century-Old Battle Over Yosemite's 'Second Valley' Heats Up

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When San Francisco voters head to the polls in a few weeks, they’ll be weighing in on one of California’s oldest environmental battles. A large part of San Francisco’s water supply is stored inside a national park – in a reservoir built in Yosemite’s Hetch Hetchy Valley.

Environmentalists all the way back to John Muir have called on the city to store its water elsewhere so the valley can be restored. A November ballot measure would require the city to develop a plan to do that. But the battle over Hetch Hetchy is just as fierce today as it was a century ago.

It’s evident when you drive up to the entrance booth in Yosemite National Park on your way to Hetch Hetchy Reservoir. The ranger hands you a brochure from the San Francisco Public Utilities Commission that reads: “20th century engineering marvel. Hetch Hetchy Reservoir is the keystone of this clean, efficient water and power delivery system.”

Why would a city agency pass out promotional pamphlets about a reservoir? Probably to respond to people like Mike Marshall.

“This belongs to the American people. And what we can do – what San Francisco can be leaders in is draining this and bringing this incredible place back to life,” says Marshall, director of Restore Hetch Hetchy.


His group has a singular goal: drain the reservoir and make the valley a second Yosemite Valley. And for the first time in decades, that goal is in reach. Measure F on the San Francisco ballot would require the public utilities commission to draw up a plan, at the cost of $8 million, for draining the reservoir and finding new water storage. In 2016, that plan would go before San Francisco voters.

Hetch Hetchy Valley in 1906. Photo: USGS.

“We thought ‘what a great debate to have.’ Now that we know what we know, should we revisit a decision 100 years ago that had huge environmental consequences?” Marshall says.

History of a Valley Turned Reservoir

Yosemite was already a national park when San Francisco went looking for a reliable water supply a century ago. The idea for a new reservoir didn’t get much traction until the 1906 earthquake, when much of the city burned to the ground. “They used that as a rallying cry and it was a huge battle in Congress,” Marshall says.

Naturalist John Muir led the fight against it. He wrote about the valley’s sheer granite cliffs and scenic waterfalls, calling it a twin to Yosemite Valley.

Eventually, he lost, and San Francisco began building the O’Shaughnessy dam in 1914 to collect water from the Tuolumne River. “Although they lost the battle, they launched a national environmental movement.”

Today the valley is under 300 feet of water, which supplies two and a half million people in San Francisco and cities around Silicon Valley. But the battle over Hetch Hetchy never really went away. In 1955, Sierra Club director David Brower made a film called “Two Yosemites.”

In 1988, the National Park Service released a study about what would happen to the landscape if the reservoir was drained.

“Within a year of the river reclaiming itself, you’ll start to see green meadows along the banks. And within a few years you’ll start to see saplings and trees come up,” Marshall says. Within 50 years, the report says, oak woodlands would return and pine trees would be 50 feet tall.

Of course, there’s the question of what happens to the water supply. Marshall says it can be stored elsewhere. “People mistakenly believe Hetch Hetchy is our only reservoir. It’s one of nine reservoirs. So what our initiative does is ask San Francisco to plan to consolidate from nine to eight reservoirs.”

Marshall says by expanding other reservoirs, using underground storage and recycling more water, San Francisco could make up for Hetch Hetchy’s storage. “We don’t recycle any water. We’ve stopped, for all intents and purposes, using groundwater, except for a little bit. Those are things we’re going to have to do anyway."

'Things Were Different Then'

“We are looking at recycled water. We are building recycled water plants. We are building groundwater pumping wells,” says Michael Carlin, deputy general manager of the San Francisco PUC.

The Tuolumne River emerges below the O’Shaughnessy dam.

“We’re looking at all those things. And to say, gee whiz, you also should just plan that your system is gone... doesn’t make any sense.” As a public employee, Carlin says he can’t take a position on the issue, but he has concerns.

The Hetch Hetchy system is reliable, he says. The water is so clean, it doesn’t require filtration. And the PUC doesn’t own all the reservoirs in the system, so Carlin says they’d have to rely on other water districts if the reservoir was drained.

“Asking them if they’re willing to store San Francisco’s water there, the answer that we’ve gotten from them at least is no,” says Carlin.

Then there’s the cost. Studies throughout the years have put it between one and 10 billion dollars.

The SFPUC has never studied it, but Carlin doubts that would help. “There have been extensive studies in the past. They have come to the same conclusion which is just a set of questions. And the issue is whether any additional study will just lead you to the same set of questions.”

The ballot measure has a number of opponents: San Francisco Mayor Ed Lee, Senator Dianne Feinstein and the Silicon Valley Leadership Group, who say it’s a huge risk, because businesses depend on reliable water.

“If we were to propose building this reservoir today in a national park, chances are it wouldn’t happen. But it happened in 1913. Things were different then,” Carlin says.

On November 6th, San Francisco voters will decide if they want to take a step toward rewriting that history.