National Geographic: In early September, at the abandoned Piute Farms marina on a remote edge of southern Utah's Navajo reservation, we watched a ten-foot (three-meter) waterfall plunging off what used to be the end of the San Juan River.
Until 1990, this point marked the smooth confluence of the river with Lake Powell, one of the largest reservoirs in the U.S. But the lake has shrunk so much due to the recent drought that this waterfall has emerged, with sandy water as thick as a milkshake.
My partner DeEdda McLean...