A San Francisco-based environmental group turned in signatures on Monday supporting an effort to place a measure on the city's November ballot that would radically reform the way much of the Bay Area gets its drinking water.

The proposal, sponsored by Sierra Club spinoff Restore Hetch Hetchy, would require San Francisco to prepare a plan to transition away from one of its primary water sources, the Hetch Hetchy Reservoir in Yosemite National Park.

Draining the reservoir would allow the Hetch Hetchy Valley, which famed naturalist John Muir once described as "one of nature's rarest and most precious mountain temples," to reappear from its submerged slumber.

"The Hetch Hetchy Valley in Yosemite National Park is an American gem," Restore Hetch Hetchy Executive Director Mike Marshall told the San Jose Mercury News. "It is one of the most extraordinary ecosystems in the world. Yosemite is one of the crown jewels of our park system, and it deserves to be whole."

Measures need 9,702 valid signatures to qualify for the ballot. Marshall said his group turned in more than 16,000.

Nearly a century ago, the O'Shaughnessy Dam was installed in Hetch Hetchy Valley to collect water from the Tuolumne River. Under the 1913 Raker Act, which permitted the dam's construction, the San Francisco Public Utilities Commission is allowed draw water from the reservoir on the condition that the city "first draw upon their own stored water to the fullest practicable extent."

Critics have argued that San Francisco has done a lousy job obtaining water from local sources.

One unlikely opponent of the dam is conservative California congressman Dan Lungren, who wrote a letter to U.S. Secretary of the Interior Ken Salazar earlier this year urging the federal government to investigate the SFPUC for violations of the Raker Act.

Local officials, who almost universally oppose the measure, have balked at the charges.

"The suggestion that San Francisco is not using its water supply efficiently is simply not true. Per person, Bay Area residents use less than half...the state's per-capita average," said California Senator and former San Francisco Mayor Dianne Feinstein in a statement to the Los Angeles Times. "Hetch Hetchy provides critical water supplies to 2.5 million people and thousands of businesses, and any effort to jeopardize that water supply is simply unacceptable."

SFPUC uses 7.5 million gallons recycled water around the Bay Area ever day for irrigation. But San Francisco currently doesn't use any local sources for drinking--although plans have been announced to drill a number of groundwater wells on the city's west side.

While San Francisco gets 100 percent of its water from the overall Hetch Hetchy system, the actual Hetch Hetchy Reservoir is only one of nine such reservoirs in a network that stretches from Sierra Nevada mountains, across the Central Valley and out to the coast. The Hetch Hetchy Reservoir holds about 25 percent of the system's water capacity.

Backers of the ballot measure plan on enlarging Don Pedro Reservoir in the Sierra Foothills as a way to replenish the storage lost by the destruction of the O'Shaughnessy Dam.

The Modesto and Turlock irrigation districts, which jointly operate Don Pedro, are not in favor of the proposal. They argue that not only is it largely unfeasible to enlarge Don Pedro, but they're loathe to share more of their region's water with the Bay Area.

On top of the water issue, San Francisco generates a large portion of its electricity from the O'Shaughnessy Dam. The 400 megawatt hydroelectric capacity of the Hetch Hetchy system would be cut by 40 percent if the dam was taken down.

If the bill to study the plan passes this November, its backers hope that San Francisco residents will approve the restoration of Hetch Hetchy Valley as soon 2016.

Check out this video about restoring Hetch Hetchy featuring actor Harrison Ford: