A group of powerful California farmers pulled their support Tuesday from a pair of massive, $16 billion tunnels that would have re-engineered the state's water system in a decisive move that dealt a major blow to the project pushed by Gov. Jerry Brown. The board of Westlands Water District, the nation's largest supplier of irrigation water to farms, voted to withdraw its participation from the project after more than an hour of tense discussions and comments from farmers who overwhelmingly concluded it was too expensive.After the vote, John Laird, secretary of the California Natural Resources Agency, said the aging water infrastructure must be modernized."Failing to act puts future water supply reliability at risk," he said in a statement. "This vote, while disappointing, in no way signals the end" of the project known as WaterFix.Tuesday's vote leaves the project's future in peril, potentially heightening a longstanding feud between typically dry Southern and Northern California, where much of the state's water originates.