Rainfall energy loss : an empirical model

Kinetic energy of a rainfall event is determined by its intensity. However, the effective kinetic energy reaching a soil surface that is responsible for detachment and transportation of soil particles is often less than the total kinetic energy of the rainfall event. This is because of the cushioning effect a film of water provides. Therefore it is essential to account for the loss in kinetic energy of a rainfall event and incorporate it in simulation models to accurately estimate soil erosion. This paper proposes a logarithmic energy loss model to estimate kinetic energy of rainfall reaching the soil surface. The model accounts for the depth of shallow overland flow and rainfall intensity. The empirical model was established through the set of data obtained from a rainfall simulation experimental setup consisting of a laboratory-scale tilting hydraulic flume, rainfall simulator and a series of sensitive piezoelectric force transducers. Slope variations were simulated by mechanically tilting the flume between 0[degrees] and 15[degrees]. Responses captured by the transducers in the form of voltage and pulses were analysed to establish the empirical model. The high Nash-Sutcliffe efficiency (E = 0.90) suggests the reliability of the empirical model and its potential for applications in soil erosion modelling.