Visit South Platte River Park in Littleton, Colorado (a suburb a few miles south of Denver) on a summer weekend and you’ll likely see dozens of people paddling, wading, fishing, or tubing on the river. A few weeks ago I was one of those tubers enjoying higher than normal flows on the South Platte, thanks to the high snowpack this past winter. As we floated on riffles and gentle rapids, families of ducks grazed at the river’s edge and trout swam beneath us. Occasionally we got caught on someone’s fishing line or bumped tubes in crowded sections of the river.