Federal officials are preparing to flood the Grand Canyon. No, not all the way.
The U.S. Department of the Interior will be pumping more water through the Glen Canyon Dam to spread an abundance of sand throughout the floor of the canyon. The move is meant to replicate pre-dam conditions and will help create new beaches for rafters and protect delicate archaeological sites in the canyon. There's enough sediment built up behind the dam to fill a football field to a depth of nearly 70 stories.
Water began flowing through the dam on Monday and will continue for five days, flattening out rapids throughout the length of the Colorado River. The sediment replenishment is designed to prevent erosion and other ecological problems that could arise as part of the dam's influence on the river.
What would it take to actually fill the Grand Canyon with water? One website puts the (very rough) estimate at 2098.5 cubic miles to a depth of 4,000 feet. At current water flows of 30,000 cubic feet per second, it would take about 327 years to fill up the canyon, which would then be the second-deepest continental lake on Earth and the fourth largest by volume.