Protestors scaled the second-story sign in front of East Bay MUD's downtown Oakland offices to illustrate their opposition to the inclusion of an expanded Pardee Reservoir in the utility's long-term plan.
"We think they shouldn't do that because we want to protect the remaining free flowing miles of the Mokelumne River for the people and the fish and the wildlife that use it today," said Katherine Evatt from the Foothill Conservancy.
As part of its 2040 water supply management program, EBMUD included a proposal to expand its main supply reservoir Pardee by building a new 400-foot dam farther downstream.
That would increase Pardee's capacity by 50 percent, raising its current level by 33 feet and flooding much of the Mokelumne River.
"It would drown that stretch of river and kill all the vegetation around it. Under existing law, in fact it would even prevent any kind of recreation from going on there. People really care about this river and they're not going to let it happen," said Ron Stork from Friends of the River.
"We spent over $6 million and over two and a half years in developing studies to assist us with these options," said EBMUD Board President Doug Linney.
But EBMUD's board maintains that in order to adequately plan for future growth in the Bay Area, all reasonable options must be explored -- although none would be pursued without widespread community support.
"The only way we're going to do a project is if we do it together. If it's a regional project that they get benefits as well as us," said EBMUD spokesman Charles Hardy.
The Pardee expansion wouldn't occur until the year 2023. But now that the board has voted to include it in its long-range plan, detailed environmental studies can begin.
Opponents say it's a process they'll move to stop in court.