Environmentalists plan to file signatures on Monday to qualify a measure for the November ballot that would create plans to drain a major water supply for San Francisco.  It's the Hetch Hetchy Valley in Yosemite National Park, which provides water for the city and about 1.5 million people nearby.

Mike Marshall, executive director of "Restore Hetch Hetchy", says it's time to rethink how San Francisco gets its water.  "It's the first time since 1908 that San Franciscans have had a chance to vote on their water system in terms of its impact on Yosemite National Park," he said.  "It comes at a moment in time when all of us are trying to figure out how can we better walk on the face of the Earth, whether it is as a city or as an individual."

The initiative would require San Francisco to come up with a plan for alternative drinking water sources, as well as a plan for restoring Hetch Hetchy and the Tuolumne River.  The plan would be due by 2016. San Francisco city officials oppose the idea.