Map of Colorado River Basin
The Colorado River begins high on Colorado's Western Slope in RockyMountain National Park. A major tributary, the Green River, begins in Wyoming. From their junction south of Moab, Utah, the Colorado River Basin encompasses Arizona, Nevada, New Mexico, California and Mexico.
Map of Annual River Flows in Western Colorado
Most of the state of Colorado's water is located on the west side of the Continental Divide in the Colorado River Basin, but the vast majority of its population is on the drier, eastern side of the Rocky Mountains. All together, the rivers located in Western Colorado account for more than 90 percent of the water that leaves the state.
Map of Colorado's Transmountain Diversions
Twelve diversion points take water from Colorado's Western Slope headwaters regions to the thirsty and ever-growing Front Range and Eastern Colorado areas. In the early days, most of the water was used for agricultural purposes. Today, cities are buying the water in increasing amounts for municipal and industrial use.
Map of Western Colorado Reservoirs
In the state, the Colorado River Basin has hundreds of reservoirs from small to large, including major reservoirs such as Lake Granby, Dillon Reservoir and Blue Mesa, the state's largest reservoir. Reservoirs are used for multiple purposes including flood control, water storage and recreation. Front Range water suppliers control many of the reservoirs in the Western Slope headwaters so they can divert water eastward. Map of the Colorado River District
The Colorado River District serves Grand, Summit, Pitkin, Eagle, Routt,Moffat, Rio Blanco, Garfield, Gunnison, Mesa, Delta, Montrose, Ouray,Hinsdale and Saguache counties.
The Colorado River District works in 15 Western Colorado counties to protect water from Front Range and downstream dominance. It was founded in 1937 in direct reaction to the Colorado-Big Thompson Project that diverts Colorado River headwaters to Northern Colorado, east of the Continental Divide.