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The rapids and the pools - Grand Canyon: Chapter D in The Colorado River region and John Wesley Powell (Professional Paper 669)

Professional Paper 669-D
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https://doi.org/10.3133/pp669D

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Abstract

Through the Grand Canyon the Colorado drops in elevation about 2,200 feet in 280 miles; most of this drop occurs in rapids that account for only 10 percent of the distance. Despite the importance of rapids, there are no waterfalls. Depth measurements made at 1/10-mile intervals show that the bed profile is highly irregular, but the apparent randomness masks an organized alternation of deeps and shallows. Measurement of the age of a lava flow that once blocked the canyon near Toroweap shows that no appreciable deepening of the canyon has taken place during the last million years. It is reasoned that the river has had both the time and the ability to eliminate the rapids. The long-continued existence and the relative straightness of the longitudinal profile indicate that the river maintains a state of quasi-equilibrium which provides the hydraulic requirements for carrying the debris load brought in from upstream without continued erosion of the canyon bed. The maintenance of the alternating pools and rapids seems to be a necessary part of this poised or equilibrium condition.

Publication type Report
Publication Subtype USGS Numbered Series
Title The rapids and the pools - Grand Canyon: Chapter D in The Colorado River region and John Wesley Powell (Professional Paper 669)
Series title Professional Paper
Series number 669
Chapter D
DOI 10.3133/pp669D
Year Published 1969
Language English
Publisher U.S. Government Printing Office
Publisher location Washington, D.C.
Description iii, 15 p.
Larger Work Type Report
Larger Work Subtype USGS Numbered Series
Larger Work Title The Colorado River region and John Wesley Powell (Professional Paper 669)
First page 131
Last page 145
Country United States
Other Geospatial Colorado River
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Additional publication details