CA's central valley is missing ~140 million acre feet of groundwater relative to historical norms, and is pumping an additional ~15 million acre feet a year. Ban that and desalinate 30 million acre feet of oceanwater at $2000 per acre-foot and you can have your cake and eat it too at a cost of 60 billion dollars a year, expand agriculture and develop a sustainable aquifer & watershed.

But central valley agriculture only makes $37 billion a year.