San Francisco residents will vote on a ballot measure this fall that seeks to drain Hetch Hetchy, the controversial 80-year-old valley-cum-reservoir in Yosemite National Park that has drawn the ire of environmentalists since the days of John Muir. The measure asks voters to decide whether San Francisco officials should come up with a new water treatment plan and study other possible reservoirs to replace Hetch Hetchy. Studies by the state and outside groups have suggested that San Francisco could feasibly collect water downstream from the Tuolumne River without the dam. While environmentalists and Republicans, including Ronald Reagan's Secretary of the Interior, Donald Hodel, back the removal, Democrats like Nancy Pelosi and San Francisco Mayor Ed Lee oppose it. "It's a Trojan Horse for those that wish to have our public tricked into believing we have an adequate substitute for the Hetch Hetchy reservoir," Lee said. "We do not."