The task of turning a desert into rich farmland has taken place over a period of 150 years. The main element is a string of retention reservoirs/recreational lakes from the high Sierra down to the foothills where water is held during the wet times (avoiding wastefuland destructive flooding) and released during the dry times for use by the farmers. The system has worked well, and has fed this nation, until the last 10-15 years when government has interfered and has allowed those reservoirs to drain down, diverting the water to the ocean where it does no good.
Think of those lakes as a pearl necklace which is now broken, allowing the water to spill and be lost. Where government has gone wrong is failing to save water during the wet times for use in the dry times. I don’t think that any of them have read the Bible recently. Remember Pharaoh and his 7 fat years followed by 7 lean years?
I saw an article in a scientific journal a few years ago suggesting that the "drought" in much of the western U.S. wasn't really a drought at all. It may very well be that we're simply emerging from 50-60 years of unusually wet weather in the West, and that the "normal" condition out there is semi-arid to desert. If that's the case, then all of the water infrastructure designed in that period may be obsolete.