As a native Coloradan, photographer Peter McBride always wondered how long it took irrigation water from his family’s cattle ranch to reach the Colorado River and ultimately the sea. That question sent McBride (with author Jonathon Waterman) on a two-year journey to follow the water. He photographed the Colorado, mostly from the air, in an effort to document where the river’s water actually goes. The results will appear in the book The Colorado River: Flowing Through Conflict (Westcliffe Publishers), due out in September. This sneak preview of McBride’s work marks the launch of our “Follow a drop of water” series, an ongoing look at some of America’s most beautiful and threatened rivers. So, how long does it take the mighty Colorado to reach the sea? The answer, these days, is: never.