"Rep. Lungren is the first member of the U.S. Congress to come out in support of this," said Ron Good, head of Restore Hetch Hetchy. "It's a breakthrough."

Lungren's endorsement of draining the 360,000 acre-foot reservoir is being announced in an opinion article the conservative Republican is sending to area newspapers. The cost of the valley's restoration is estimated at as much as $10 billion, although Good said environmentalists believe the cost will be far less.

Congress would have to approve the work, however, and that's where the big rub is. Sen. Dianne Feinstein, D-Calif., has been longtime opponent of the restoration idea. No other Bay Area Democrat in Congress has endorsed the idea, especially House Speaker Nancy Pelosi, D-San Francisco.

But Lungren is not exactly striking out on his own, either. The Bush administration has included $7 million in the Interior Department's 2008 budget to study restoration.