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Southern Colorado Plateau Alluvial History and Processes

For additional information, please visit http://esp.cr.usgs.gov/info/sw/scpalluvial/.

River basins of the southern Colorado Plateau provide excellent records to understand the timing, magnitude, and extent of recent arroyo cutting and aggradation in the Southwest. This information will be used with past stream flow estimated from tree-ring studies to test for correlation between climate variation and alluvial activity. Changes in channel paths are being measured in the selected basins to examine the response of the system to unusual weather patterns such as El Niño-Southern Oscillation. A major outcome of this research will be a clearer understanding of the role of human activity in fluvial erosion. Work on the Paria River basin (southern Utah and northern Arizona) is leading to the development of a new model of arroyo cutting and valley-fill aggradation.

Comparisons of the effects of climate on post-1900 river processes in the Mojave Desert and southern Colorado Plateau reveal roughly similar patterns of response that can be related to short-term climate change, such as El Niño-La Niña conditions and the Pacific Decadal Oscillation. The analysis will provide important guidance for land management and arid-land restoration over the next several decades.