I disagree about us needing more water. Our Ag industry is simply not as important as it would like everyone to believe. There is common misconception that food prices would skyrocket and people would go hungry if California's Ag production was severely cut short. This is especially true here in the Central valley where I was raised and live. People here are led to believe (by agribusiness propaganda) that California's economy would sink without Ag. It's not true at all.
California grows almost no staple crops, like wheat and corn. Instead we dominate the pistachio, almond, strawberry and artichoke markets. We also grow a shitload of alfalfa, a water intensive crop which at the present time is being shipped to China to feed their cows.
Food is a world-wide industry which is extremely agile. Any shortage in one area of the world can easily be filled by another.
The most sensible solution is to regulate water so as to price farmers out of production in times of drought. When the rains come back (and they will), they can grow to their heart's content. Ag is 2% of California's economy. It's not worth the investment.