Raindrop-induced and wind-driven soil particle transport

A wind tunnel study under wind-driven rains was conducted to determine the combined effect of rain and wind on the rainsplash transport process. The rains driven by horizontal wind velocities of 6, 10 and 12 m s(-1) were applied to three agricultural soils packed into a 20 x 55-cm soil pan placed at both windward and leeward slopes of 4.0degrees, 8.5degrees and 11.3degrees. Transport rates were measured by trapping the splashed particles at set distances in the upslope and downslope directions, respectively, for windward and leeward slopes. Rainsplash transport under wind-driven rains was adequately described (R-2 = 0.93) by relating the transport rate to the rain impact pressure and wind shear velocity by log-linear regression technique. Average trajectory of a raindrop-induced and wind-driven particle was also adequately predicted by the momentum loss per unit time per unit length of travel (u(*)(2)/g)., The travel distance is found to be three times greater than the path of a typical saltating sand grain. (C) 2002 Elsevier Science B.V. All rights reserved.