Rain Splash on Sheetwash

October 20, 2014

Rain Splash and Sheet Wash epod

Photographer: Stan Celestian; Stan's Web site   
Summary Authors: Stan Celestian; Jackie Phillips

During summer monsoon rains in Arizona many desert areas experience sheetwash. The impact of raindrops on a bare desert surface can easily disturb small sand sized particles, as shown in the insert. Each impact moves the grains in a back and forth motion with little if any net direction. However, on even a subtle slope the small movements of the particles and water will result in a downslope movement -- sheetwash. Without vegetation to hold the soil and absorb water, bare surfaces such as these are susceptible to higher rates of erosion as well as to flooding.