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WATER RESOURCES RESEARCH, VOL. 41, W05021, doi:10.1029/2003WR002519, 2005

Changes in the water surface profile of the Colorado River in Grand Canyon, Arizona, between 1923 and 2000

Christopher S. Magirl

U.S. Geological Survey, Tucson, Arizona, USA


Robert H. Webb

U.S. Geological Survey, Tucson, Arizona, USA


Peter G. Griffiths

U.S. Geological Survey, Tucson, Arizona, USA


Abstract

In 1923, a U.S. Geological Survey expedition surveyed the water surface profile of the Colorado River through Grand Canyon with theodolite and stadia rod. In 2000, lidar overflights collected topographic data centered on the river corridor, allowing construction of a new water surface profile and detection of change in the profile since 1923. By registering the surveys with respect to each other on the basis of 11 locations that were independently determined to have been unchanged between 1923 and 2000, 80 rapids were directly compared for change between 1923 and 2000. The average change for all measured rapids was +0.26 m, indicating net aggradation of the coarse-grained alluvium forming the rapids throughout Grand Canyon. In addition, comparison of the two water surface profiles showed enhanced pool-and-rapid morphology. While 50% of the total drop of the river occurred in just 9% of the river distance in 1923, that value increased to 66% by 2000.

Received 24 July 2003; accepted 28 February 2005; published 24 May 2005.

Keywords: debris flows; Grand Canyon; lidar; rapids; water surface profile.

Index Terms: 1821 Hydrology: Floods; 1825 Hydrology: Geomorphology: fluvial (1625); 1810 Hydrology: Debris flow and landslides; 1808 Hydrology: Dams; 1861 Hydrology: Sedimentation (4863).

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Citation: Magirl, C. S., R. H. Webb, and P. G. Griffiths (2005), Changes in the water surface profile of the Colorado River in Grand Canyon, Arizona, between 1923 and 2000, Water Resour. Res., 41, W05021, doi:10.1029/2003WR002519.