Resistance of Coarse-grained Particles against Raindrop Splash and Its Relation with Splash Erosion

Abstract

Raindrop splash, which is the most critical factor determining detachment rate of soil particles, is the result of complex interplay between the erosivity of raindrops and splash detachability of soils. When the applied erosivity exceeds the intrinsic resistance (splash detachability) of soils, raindrop splash erosion will be initiated. However, studies on the elucidation of underlying process in the soil detachment by raindrop splash are very limited. This study investigated the resistance of coarse-grained particles to raindrop splash through both theoretical analysis and experiments. In addition, the splash erosion rate was evaluated by employing both erosivity (property of raindrop) and splash detachability (property of soils) variables. Results indicated that the median sand particle size was the primary variable determining the splash rate of coarse-grained particles, while, the effect of particle shape and relative density on raindrop splash was minimal. Thus, threshold kinetic energy and splash detachability factor were expressed in terms of median sand particle size. Finally, experimental results were compared with the theoretical model through the comparison of the border between splash and no splash, and a good agreement between those two was observed in this study.