We are familiar with pipes, pumps, siphons, canals. etc. It is engineering of a routine, but massive scale to perform a major shift like this. The question is cost? Water can be pumped with solar/wind energy. With major area on their way to become parched deserts - except for water. What is the Value of all California crops every year - that can go to zero every year versus the one time cost of a major water project = a spend once, plus maintain = get a permanent 'annual California crop every year' Water project, by their nature are long lived and low maintenance.