This story is part of a special National Geographic News series on global ... Some of the world's great rivers, from the Colorado to the Indus, don't always reach their ends because people have ...

This story appears in the February 2012 issue of National Geographic magazine ... Behind you, the Colorado River is trenching a deep meander from the Glen Canyon Dam toward the Grand Canyon.

Most of the collected runoff, if it hasn't vaporized or died in a mudflat, swells the Colorado River. By the time the ... of the roughly 30 parks and other national preserves that make the heart ...