PREDICTING SOIL DETACHMENT BY RAINDROPS

The process of soil erosion by water across a landscape is modeled by mathematically linking the subprocesses of detachment, transport, and deposition of sediments. Contemporary soil erosion models represent the raindrop detachment rate as a nonlinear function of rainfall intensity, the parameters of which have to be experimentally derived from interrill erosion plot data. We describe a model that predicts the rate of soil detachment by multiple raindrops impacting on a bare soil surface. The model depends on parameters of a soil-strength-dependent single-drop detachment model and a bivariate raindrop-size distribution function. The simulated data is analyzed to represent raindrop detachment rate as a linear and a nonlinear function of intensity. Equations that relate the parameters of soil detachment rate vs. intensity functions to the parameters of the single-drop detachment model are presented.