I write this sitting in the Phoenix airport, where America West has seen fit to deposit me en route to Seattle. Ah, the glorious efficiencies of the hub-and-spoke model.
Flying over Arizona, I couldn't help but notice a few things. Almost all of the surface water is contained in manmade structures, mostly canals and swimming pools. What little natural water I saw for the last hour of flight was so dirty that I thought I was viewing dusty riverbeds until the sun glinted off their surfaces. It is impossible to ignore, with the macroscopic perspective provided by altitude, that water is not an abundant natural phenomenon around here.
That would deeply concern me if I were a resident. After all, human survival doesn't depend on too many things, but a steady water supply is definitely among them. I doubt I will ever wish to live in a place where, in the case of a catastrophic failure of human infrastructure, I wouldn't be able to walk to a source of drinkable (at least with simple mechanical filtering) water.
Maybe I'm just a paranoid nut for concerning myself with catastrophic failures of human infrastructure.