Those who manage and use reservoirs in the western United States are used to cycles of boom and bust: wet periods fill reservoirs, while droughts empty them. But as the Southwest enters what looks like an uncertain future of climate change, there's evidence that Lake Powell may be in for a particularly hard time.
Two hundred miles upstream from Glen Canyon Dam, the Colorado River roars through Cataract Canyon in a rust colored tumult, thick with silt and clay. Each year, the Colorado and its tributaries carry, on average, some 61 million cubic yards of sediment into Lake Powell, enough to fill more than 200,000 railroad boxcars.
More than a century ago, a Harvard undergraduate named Alfred Vincent Kidder came out west. He came to volunteer at some archaeological sites that had just been excavated - places like Mesa Verde and other ancient ruins.
Nicknamed Ted, he had little more than a tape measure, a cheap compass and a Kodak camera. But the experience changed his life - and the course of southwestern archaeology.