The lifeblood of Phoenix and Tucson is the Central Arizona Project, a mighty canal dug from the Colorado river hundreds of miles away. Although urban Arizona is notoriously wasteful in water use, the canal itself supposedly only loses 3-4% of its water to evaporation. (I had previously thought it a lot worse)

That fact surprises me, though I won't dispute it. Nonetheless, it's an ominous sight straight out of Cadillac Desert, snaking among the impossibly green golf courses and exotic palms.