In 1910, voters in San Francisco approved a $45 million bond issue for the construction of a water system on the Tuolumne River.
In 2010, city residents could vote on a proposal to tear out a key part of the system — Hetch Hetchy Reservoir in Yosemite National Park.
Restore Hetch Hetchy, the group leading the effort, aims to get the measure on the November ballot.
A vote in favor would not spring the wrecking crew into action, as the city still would have to find alternatives for storage, possibly in an enlarged Don Pedro Reservoir.
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But passage would make it clear that San Franciscans want Hetch Hetchy Valley restored to its pre-dam splendor, said Mike Marshall, the group's executive director.
"If we get it on the ballot, it will be a bit of a game-changer," he said.
The details of the measure, including how to pay for dam removal and other work, are being discussed.
A 2006 state study estimated a $10 billion cost to raze the dam, restore the valley and replace the lost water supply. Restore Hetch Hetchy contends that all of this could be done for $1 billion to $3 billion.
The group suggests that part of the money could come from the state and federal governments and from private donations. It argues that the restoration would provide a natural wonder for all to enjoy while reducing the state's water and hydropower supplies by less than 1 percent.
Opponents of the removal generally agree that the reservoir should not have been built in Yosemite, but they say reducing water storage in a drought-plagued state would be foolish.
Critics include the San Francisco Public Utilities Commission, which runs the system.
"Our city is facing a $522 million budget deficit, and there certainly are other priorities," said Tyrone Jue, director of communications for the commission. "Quite frankly, (the campaign) doesn't take into account the 2.4 million people in the Bay Area who depend on water from Hetch Hetchy Reservoir."
Opposed from the start
The ballot measure would be one more chapter in a saga that started more than a century ago.
John Muir and fellow environmentalists considered Hetch Hetchy Valley as magnificent as Yosemite Valley to the south. They suffered a bitter defeat in 1913, when passage of the federal Raker Act allowed the city to build the dam.
It took 21 years to complete all of the reservoirs, tunnels and other waterworks. Since 1934, the system has supplied water to San Francisco and several nearby cities. It also generates hydropower for the Modesto and Turlock irrigation districts and other users.
Environmentalists seethed for decades about allowing the 312-foot-tall dam in a national park. They saw a ray of hope in 1987, when Interior Secretary Donald Hodel suggested removing it. Studies and debate followed, but the dam still stands.
Marshall said his group decided last year to focus on educating San Franciscans about how the valley could be restored without reducing their water supply.
The group contends that even without the dam, river water could be pumped into the diversion tunnel downstream from Hetch Hetchy. It suggests increased use of other parts of the system, including Cherry Creek and Lake Eleanor in the Yosemite area and Calaveras Reservoir in Alameda County.
Marshall said the city could increase water conservation and recycling, along with tapping groundwater.
Enlarge Don Pedro?
Another possibility is enlarging Don Pedro, owned by MID and TID and nearly six times as big as Hetch Hetchy. San Francisco would have to negotiate with the districts.
MID General Manager Allen Short said removing Hetch Hetchy would reduce the state's ability to capture excess river flows and endure droughts.
"California needs all the water storage and power that it has now, plus more," he said.
Restore Hetch Hetchy could get the measure on the ballot by collecting about 47,000 signatures from registered voters in the city or persuading the San Francisco Board of Supervisors to place it.
If time is tight this year, the measure could wait until November 2011, Marshall said.
His group, which used to be based in Sonora, had about 1,800 members and a budget of about $250,000 as of last year.
One of the board members is Jerry Cadagan of Sonora, a retired lawyer. He takes issue with people who say the reservoir is a mistake that should be allowed to remain.
"I have a different train of thought," he said. "When you make this big of a mistake, correct it."
Bee staff writer John Holland can be reached at email@example.com or 578-2385.