Even if Climate Change does not occur (increased temperature and less rainfall) we know from tree ring records that droughts in the west of 30 or more years were not uncommon. Our current drought so far is only half this length. The current State assured supply rules fall will short of assuring supplies under such long term drought. If we do not plan for such now and just wait until water supplies are curtailed, actions to respond will either be very expensive or impossible. If Climate Change does impact temperature and rainfall, the situation will be much worse.