Dark Canyon

and its Notorious Rapid

Dark Canyon Rapid; May 1963: Gregory Crampton; Special Collections, J. Willard Marriott Library, U of U

Dark Canyon Rapid Overview, looking upstream from river left, George Simmons 1956

Running Dark Canyon Rapid, Grant Reeder 1960s, courtesy of Stuart Reeder

In the confines of the main canyon’s limestone, opposite Dark Canyon’s mouth, a steep wall on river right added to the constriction of the river. Rocks on the left, wall on the right. [insert gritted teeth, tight life jacket, brown shorts]

The largest tributary to the Colorado River through Cataract Canyon used to create one of the fiercest rapids on the entire run through the Colorado.

As the river bends around and changes its flow from the south to the west, the side canyon pushed out a large debris fan, damning the river to create a 15-20 drop in elevation.

Dark Canyon Rapid Elevation Profile, 1921 USGS Birdseye Survey

Scouting Dark Canyon Rapid, 1950s, George Simmons

Will we ever see it again?

Visual of Historic Side Canyon with various Reservoir sediments and Side Canyon Alluvial Deposition

Likely, no…

Dark Canyon is such a huge drainage that in the past 50 years, reservoir or no reservoir, that rapid likely would have changed in some form.

The very thing that made Dark Canyon so notorious (a huge side canyon that flowed into the Colorado at a very constricted location) may hold the same factors that may help it have a chance to yet again have a fearful reputation…