Gov. Jerry Brown went back to the future Wednesday, saying water problems have confronted him, his father’s governorship and their predecessors as they sought ways to get northern water to the south. Brown said delta-linked proposals had been studied for decades, with perhaps a million personnel-hours spent looking at the plan. “Until you put a million hours into it, shut up!” Brown, defending the proposal, told a gathering of hundreds of people at a statewide at a conference of the Association of California Water Agencies. Brown’s comment drew applause.