More than 15,000 signatures were turned in Monday by supporters of an initiative for the November ballot that would force San Francisco to formulate a plan to dismantle its water system in Yosemite National Park's Hetch Hetchy Valley.

The Yosemite Restoration Campaign gathered 15,806 signatures and turned them in this afternoon at the city's Department of Elections following a news conference on the steps of City Hall.

The initiative "is designed to take San Francisco from last in the state to first in the nation in terms of managing its water resources," said Mike Marshall, campaign director for the initiative. "We can do better."

Elections officials have 30 days to verify that at least 9,702 of the signatures are from registered San Francisco voters to qualify the measure for the ballot.

Marshall said the city has refused to consider a plan to dismantle the reservoir in Hetch Hetchy, which was created in 1923 by damming the Tuolumne River.

If the initiative is approved by voters in November, it would force the city to come up with a plan to improve its use of local water supplies and stop using water from Hetch Hetchy by 2035.

The plan would be crafted by a five-member board, and would have to be approved by voters in 2016.

Opponents of the initiative issued a statement today pointing out that nearly every local politician, including Mayor Ed Lee, all 11 members of the Board of Supervisors and Democratic Leader Nancy Pelosi, have come out against it.

Marshall said, "The issue isn't about what the politicians decide ... I think most San Franciscans would like to see Hetch Hetchy restored."

The opponents, a coalition called Citizens for Reliable Water and a Healthy Environment, said in a statement that the $8 million planning process set up by the initiative would put San Francisco "on a path to destroying one of the world's greatest engineering feats."