The Yampa River is considered the only free-flowing river left in the Colorado River Basin -- and one of the last in western America. Nature photographer John Fielder, who lives in Summit County, insists that it stay that way. To advocate for the river's "wildness," he hopped into a raft, along with writer and professor Patrick Tierney. The two compiled essays and images from their trip, along with a few historical tidbits. It fuels a book called, "Colorado's Yampa River: Free Flowing and Wild from the Flat Tops to the Green." Fielder spoke with Colorado Matters host Nathan Heffel.