[6][3] The drainage basin of the Gunnison collects water from different habitats, such as forests and alpine meadows, located along the Continental Divide.

The Gunnison River Basin is popular for recreational activities such as fishing, rafting, boating, camping, hiking, and rock climbing.

[7] Contamination of the Gunnison River with selenium and mercury results from irrigation of high-selenium soils derived from the Mancos Shale and from mineral mining.

Escalante noted that Rivera thought it was "the great Rio del Tizon", the long-used Spanish name for the lower Colorado River.

In subsequent years, however, the river was renamed for U.S. Army Captain John W. Gunnison of the Topographic Engineers, who was ambushed and killed by Pahvant Utes while mapping a trail west in Utah Territory in 1853.

The designated area begins 200 yards below the Crystal Dam and stretches through the Black Canyon to the confluence of the North Fork and Gunnison rivers.

[11] Part of the river's water is diverted to irrigate the Uncompahgre Valley via the 5-mile-long (8 km) Gunnison Tunnel, which was built between 1905 and 1909.

The decree set a flow regime that "will protect the water-dependent resources of the Black Canyon and help restore the ecological balance in the river system disrupted by three federal dams immediately upstream of the Park.

"[13] The Gunnison River is threatened by climate change, demand for water resources, and ongoing challenges regarding selenium contamination.

[22] Agricultural areas in the Gunnison River Basin are heavily farmed and provide large amounts of sediment during the growing months.

[26] Mercury in the Gunnison River comes from human activities including surface mining and burning fossil fuels such as coal.

The Colorado pikeminnow is especially vulnerable to high concentrations of mercury as its life cycle is relatively long and the distances they travel for migration are especially far.

Salinity is being addressed by implementing local investments into the water use infrastructure by converting old systems to direct pipeline and sprinklers to help reduce the amount of runoff into the Gunnison.

[35] As climate change reduces stream flow in the Gunnison River, future concentrations of both selenium and mercury will continually rise.

This has led water managers and stakeholders from the Gunnison River Basin to review options in order to reduce the impact of climate change.

[36] In addition, the Clean Water State Revolving Fund has awarded the Colorado Department of Public Health and Environment almost $13 million for future research and development along with pollution control and mitigation attempts.

[37] Most recently, the Gunnison River will soon be evaluated by state water quality officials to determine if the improvement programs have been successful in reducing the selenium and salinity levels toxic to the endangered fish.