Troy explores in depth the water needs of Southern California and Arizona, and the power hungry infrastructure needed to deliver that water. In the process he delivers some startling information.
For Southern California, "to get from the Sacramento River to the crest of the Tehachapi Mountains, one year's worth of water requires just slightly less electricity than the combined amount used by all residences in the city of Los Angeles."
"But despite modern materials and engineering methods, the water delivery system of the American West is comparatively ephemeral - for the sole reason that it depends so heavily on energy. We have built major cities in response to the engineered availability of water, and we did so in an era when energy was cheap and apparently plentiful. But ultimately the price of energy might be as destructive to our public water supplies as invading barbarians were to Rome's."