Lake Mead is shrinking. The Great Salt Lake is shrinking. The Salton Sea is shrinking.Not just in the American West, but in Africa, Asia, and the sub-Arctic reaches of the globe, lakes are disappearing. Theres not just one reason: its a combination of agricultural overuse, drought, and climate change. The current, terrible drought in the American West could be just a hint of whats coming. In the next century, scientists have predicted that a megadrought will desiccate Americas center and southwest, putting even more stress on freshwater lakes, particularly the reservoirs that were man-made to begin with.And when these disappear, they reveal the secrets that had been hidden beneath the surface—now-useless infrastructure, once lively settlements, and, if they dry all the way, fine-grained and often alkaline dust thats picked up by the wind and blown across the surrounding area.