Gunnison River, CO

The Gunnison River is a tributary of the Colorado River, approximately 180 mi (290 km) long, in the U.S. state of Colorado. It is the fifth largest tributary of the Colorado River, with a mean flow of 4320 ft³/s (122 m³/s).

It rises in west central Colorado, in eastern Gunnison County, formed by the confluence of Taylor and East rivers. Just past the town of Gunnison, the river begins to swell into the expanse of Blue Mesa Reservoir, a 36-mile (58 km) long reservoir formed by Blue Mesa Dam, where it receives the Lake Fork of the Gunnison. Just downstream it is dammed again to form Morrow Point Reservoir, then just downstream of that dammed for the final time to form Crystal Reservoir. The reservoirs produce hydroelectric power and supply water for the surrounding areas for both municipal and irrigation use. The reservoirs are the upper part of the Black Canyon of the Gunnison, one of the longest, narrowest, and deepest gorges in the world. Below Crystal Dam it begins to roar through massive cataracts and flows through the deepest part of the gorge. At the outlet of the canyon it receives the North Fork River, then downstream near Delta is joined by the Uncompahgre River. It then winds through desert canyonlands until it empties into the Colorado near Grand Junction, carrying almost as much water as the former.

The Gunnison River ranges in width from 100 to 1000 feet (30 to 300 m) and 3 to 50 feet (1 to 15 m) in depth. The river's powerful current and many rapids make upstream travel nearly impossible. It is navigable for small craft throughout its course and by larger boats below the Black Canyon. Parts of the Black Canyon are unnavigable to any sorts of craft because of giant cataracts. Navigation through the entire canyon is dangerous and for experienced boaters only.