I feel california should massively invest in desalination plant. It wouldn't solve everything, but at least they would have something to drink (not sure if it would be profitable for most plantation and cultures).
See also:<p>'California is not in drought'<p><a href="https://news.ycombinator.com/item?id=27068716" rel="nofollow">https://news.ycombinator.com/item?id=27068716</a>