7068

• UCREFRP Catalog Number: 7068
• Author: Bishop, B. A. and D. B. Porcella.
• Title: Physical and Ecological Aspects of the Upper Colorado River Basin.
• USFW Year: 1980.
• USFW - Doc Type: 17-55
• Copyright Material: YES

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Chapter 2

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PHYSICAL AND ECOLOGICAL ASPECTS
OF THE UPPER COLORADO RIVER BASIN

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A. Bruce Bishop,* Donald B. porcella*

An Overview of the Upper Colorado River Basin

The natural physical setting of the Colorado River Basin is best

characterized by the word diversity. The descriptions of John Wesley

Powell (1895), as he explored the Colorado River and its canyons, elo-

quently depict the intimate relation of the river and the lands from

which its flows arise:

All winter long snow falls on its mountain-crested rim,
filling the gorges, half burying the forests, and cover-
ing the crags and peaks with a mantle woven by the winds
from the waves of the sea. When the sU1lllller sun comes
this snow melts and tumbles down the mountain sides in
millions of cascades. A million cascade brooks unite to
form a thousand torrent creeks; a thousand torrent creeks
unite to form half a hundred rivers beset with cataracts;
half a hundred roaring rivers unite to form the Colorado.

Consider the action of one of these streams. Its source
is in the mountains, where the snows fall; its course,
through the arid plains. Now, if at the river's flood
storms were falling on the plains, its channel would be
cut but little faster than the adjacent country would be
washed, and the general level would thus be preserved;
but under the conditions here mentioned. the river con-
tinually deepens its beds; so all the streams cut deeper
and still deeper, until their banks are towering cliffs
of solid rock.

For more than a thousand miles along its course the Colorado
has cut for itself such a canyon.

*Utah Water Research Laboratory, Utah State University, Logan, Utah.

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