Rivers and Streams

A turbulent river with white rapids runs through a steep canyon. Trees and green shrubs are on the riverbank. Small rocks are in the foreground. — Gunnison River at high flows after spring snowmelt
NPS/C. Roundtree

A diagram shows mountains in grey shaded areas and a river in blue. Arrows denote where spring snowmelt drains into the river. — Tributaries to the Gunnison River drain from the West Elk Mountains, San Juan Mountains, and Uncompahgre Plateau.
NPS graphic

Gunnison River

The Gunnison River headwaters start at the confluence of the Taylor River and East River. Snowmelt feeds tributaries to the Gunnison River from the West Elk Mountains, Sawatch Mountains, San Juan Mountains, and the Uncompahgre Plateau. The river was previously known as the Grand River, in addition to other names before the mid-1800s. It was renamed after John Williams Gunnison, an U.S. army officer who led expeditions to find a railroad route through the Rocky Mountains and Black Canyon.

The river runs about 180 miles (290 km) in a western direction before joining with the Colorado River near Grand Junction, Colorado. 14 miles (22.5 km) of the Gunnison River flows within Black Canyon of the Gunnison National Park.

For the past two million years, the Gunnison River has moved sediment, rocks, and gravel to erode through volcanic, sedimentary, and Precambrian basement rocks. Over time, the waters carved a steep canyon nearly half a mile deep. The estimated rate of erosion is one inch (3 cm) per 100 years. Today, the river moves turbulently through the canyon bottom. Carrying grit and gravel, it continues its eroding power.

From above, visitors can see the river and hear rapids echo up the canyon walls. Black Canyon is so vertical that the river drops around 43 feet (13 m) per mile. The river’s steepest point at Chasm View drops 240 feet (73 m) per mile.

Steep dark canyon with large grey boulders and a river flowing. A small waterfall cascades over the rocks. Green vegetation is along the riverbank. — The Gunnison River has a steep river gradient around 43 feet (13 m) per mile.
NPS

A River Changed

When the park was established first as a National Monument in 1933, the Gunnison River was free-flowing through the canyon. However, as seen today, that is no longer the case. Before reaching the park, the Gunnison River is dammed to create the Wayne N. Aspinall Storage Unit. The Wayne N. Aspinall Unit is one of the four main units of the Colorado River Storage Project (CRSP), a project to provide water storage for the Upper Colorado River Basin states of Colorado, Wyoming, New Mexico, and Utah.

Between 1965 and 1976, three dams created three reservoirs in the upstream Curecanti National Recreation Area: Blue Mesa Reservoir, Morrow Point Reservoir, and Crystal Reservoir. The reservoirs are used for both water storage and hydroelectric power. Water from several high mountain streams empty into the reservoirs, contributing the overall flow. The Gunnison Tunnel, located just east of the park boundary at East Portal, also diverts water from the Gunnison River towards Montrose for industrial purposes. Once it reaches the national park boundary, it resembles a river yet again.

Due to the upstream changes in flows and river dynamics, the National Park Service secured a Federal Reserve Water Right in 2008. This water right ensures a spring snowmelt peak flow through Black Canyon that mimics the natural hydrograph and the resulting natural processes (such as vegetation scouring and erosion).

River Characteristics

Within the park, river is steep, fast, and almost unnavigable. It is characterized by large boulders, pools, difficult rapids, and a powerful current. Even the most experienced boaters must portage, or carry a boat, through sections. Shorelines are narrow, and the river touches canyon walls in some places. Riparian vegetation is minimal due to powerful spring peak flows scouring the narrow canyon bottom.

Red Rock Canyon, a tributary near the western park boundary, flows into the Gunnison River before it continues into the Gunnison Gorge National Recreation Area (BLM). The Smith Fork, North Fork, and Uncompahgre rivers flow into the Gunnison River before Dominguez Canyon. After leaving the canyon, the river eventually empties into the Colorado River.