changed the course of Aaron Million’s life. One day in 2002, when he was a resource economics master’s student studying in a Colorado State University library basement, he came across a 1918 survey and had a “lightbulb moment.” The map showed a 41-mile crescent of the Green River—a tributary of the Colorado River that mainly runs through Wyoming and Utah—swooping through Colorado’s northwest corner. “I’ve cowboyed that river,” Million, who comes from a ranching family, recalls, but “I had frankly forgotten
