A study funded by the Natural Resources Defense Council concludes that "Climate change will impact water supplies, exacerbating existing pressures on water resources caused by population and economic growth" putting most of Arizona in their extreme water supply vulnerability category [right, credit NRDC].
Meanwhile, federal officials reported in August that Lake Mead is at risk of dropping below the 1,075 foot elevation which would trigger an agreement by the 7 states with claims to Colorado River water according to the New York Times, with reduction in water deliveries to Arizona and Nevada. However, water managers could send more water from Lake Powell downstream to Lake Mead to avoid the cuts.