Garrett Rue grew up fly fishing in central Colorado, often surrounded by mountains stained amber and maroon, and hiking along streams that seemed to borrow those colors. Sometimes he would cast for native trout and come back with nothing—because there was nothing to catch. Then he started hearing stories about people in nearby mountain communities who couldn’t drink their own water. He began to wonder: “These streams have problems supporting ecosystems, and they’re not usable for drinking. What’s going on here?”