The Upper Colorado River Watershed: Headwaters for one of North America's Most Iconic Rivers

The Upper Colorado River watershed spans almost 2,000 square miles in north-central Colorado and is the headwaters for the mighty Colorado – one of North America’s most iconic rivers.


Snow melt from long, cold winters feed the rivers and streams that make up the Upper Colorado River watershed. Annual flow varies widely depending on snowfall and time of year, with anywhere from under 100 cubic feet to over 10,000 cubic feet flowing through the watershed. Flows are highest in the spring and early summer, when winter’s snowfall melts under the hot Colorado summer sun, and lowest in the fall, after snow in the mountains has melted but before winter has begun.  

Nearly 40 million people depend on water from the Colorado River, with over two million people in the Colorado front range alone depending on the Upper Colorado River watershed for their daily water needs. Flowing through seven states and two countries, beginning its journey high along the Continental Divide in the Rocky Mountains. Two major water diversions – Adams Tunnel and Moffat Tunnel – and nine reservoirs (Grand Lake, Shadow Mountain Reservoir, Lake Granby, Willow Creek Reservoir, Monarch Lake, Meadow Creek Reservoir, Windy Gap Reservoir, Williams Fork Reservoir, Wolford Mountain Reservoir) channel water for human use. Annual diversions through the Moffat Tunnel collection system alone average just over 45,000 acre feet, moving water that would flow west to the Pacific Ocean to east of the continental divide.

The health of the Colorado river starts in its headwaters. The quality and quantity of water in a river is intrinsically bound up with what happens on the land surrounding its shores, or its watershed. A watershed is the area of land where runoff from rainfall and snow melt feed into a larger body of water, such as a lake or river.

UCRWG Target Watershed Area

UCRWG identifies nine sub-watersheds in our target area:

Blue River

Gore Canyon/Colorado River

Fraser River

Middle Upper Colorado River

Muddy Creek

Troublesome Creek

Upper Colorado River

Williams Fork

Willow Creek

The water that flows through our watershed is the life blood for the plants and animals that call the High Rockies home, with a number of high altitude terrestrial and aquatic species dependent on the waters of the Upper Colorado River. The streams and rivers that compose the Upper Colorado River watershed are home to a variety of trout, sculpin and dace, while the presence of mayflies, stoneflies and caddis flies indicate healthy water.

Land uses throughout the watershed vary, with human activity impacting water quality and quantity. Human uses of the land range from rural to urban, with ranching, logging and development all impacting the flow of our rivers and streams.

The Upper Colorado River also serves as an outdoor playground for thousands throughout the year, with skiing and snowmobiling in the winter and golfing, rafting and fishing in the summer. All of these activities and uses influence the health of our watershed, and are closely linked to both water quality and quantity.