Waters that fill the South Platte River in Colorado, start high in the Rockies and bring fresh flows that nourish cities and farms on the eastern plains. As creeks and streams pick up volume they're also picking up contaminants along the way. A recent study found a range of pharmaceuticals, from heart medication to birth control chemicals, high up in the watershed. Does that mean humans shouldn't hike in the high country because they might inadvertently affect the water? Absolutely not. There are easy ways to enjoy the outdoors, yet leave no trace behind.