Exponential Distribution Theory and the Interpretation of Splash Detachment and Transport Experiments

Abstract

Soil detachment and transport by rainsplash is usually the first step in soil loss and sediment transport. It can be measured using a variety of approaches, including splash cups, trays, and boards. However, the results of splash experiments are affected by their geometry and not readily translated into generally applicable parameters. In this study, we develop a theory that can be used to interpret splash experiments. It is based on the assumption that the spatial distribution of particles splashed from a point source can be described by an exponential decay function, for which there is considerable support in the literature. The theory is evaluated for the cited experimental techniques, partly with the use of a numerical model. It is made clear that conventional measurements of splash and the true rate of detachment by splash are two different entities that can be linked if the average splash length is known. In principle, the theory is not valid for a sloping surface, but analysis of the magnitude of the error involved indicates that in many cases good estimates of detached amounts can still be obtained.