Water sustainability of ancient civilizations in mesoamerica and the American Southwest

Many civilizations, which were great centers of power and culture, were built in locations that could not support the populations that developed. Throughout history, arid and semi-arid lands seem to have produced more people than they can sustain. I will attempt to make comparisons between civilizations of the past in Mesoamerica and the American southwest and the present world in the context of water resources sustainability. Water has always been a very important factor in the development and survival of societies. A central theme of this paper is very simply, the ancients have warned us.