Channel change on the Santa Cruz River, Pima County, Arizona, 1936-86

Open-File Report 93-41
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Abstract

The Santa Cruz River, an ephemeral river that drains 8,581 square miles in southeastern Arizona, has a long history of channel instability. Since the late 19th century, lateral channel erosion has caused extensive property damage, particularly in Pima County. During the flood of 1983, about $100 million damage was caused in the Tucson area alone; most damage resulted from bank erosion on the Santa Cruz River and its tributaries. The nature, magni- tude, location, and frequency of channel change on the Santa Cruz River were highly variable in time and space from 1936 through 1986 along a 70-mile reach in Pima County, Arizona. Four mechanisms of lateral channel change--channel migration, avulsion and meander cutoff, channel widening, and arroyo widening--were identified on the Santa Cruz River. The dominant mechanism in a reach depends on channel morphology and flood magnitude. The dominant vertical change has been degradation. The timing and magnitude of channel change at a particular location are controlled primarily by hydroclimatic factors such as magnitude, duration, intensity, and frequency of precipitation and floods. The location of channel change and its magnitude in response to a given discharge are controlled largely by topographic, geologic, hydraulic, and artificial factors. Although much of the present morphology of the Santa Cruz River is the result of recent large floods, a direct link between hydroclimatic con- ditions and channel change is not always evident because resistance of the channel to erosion varies with time. (USGS)

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Channel change on the Santa Cruz River, Pima County, Arizona, 1936-86
Series title Open-File Report
Series number 93-41
DOI 10.3133/ofr9341
Edition -
Year Published 1993
Language ENGLISH
Publisher U.S. Geological Survey ; U.S.G.S. Earth Science Information Center, Open-File Reports Section [distributor],
Description vi, 65 p. :ill., maps ;28 cm.
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