Hydrophysical model of soil erosion: a basic equation and influence of bed load and suspended sediment on soil detachment by shallow water flow

The hydrophysical model is based on the three premises. According to the first and the second premises soil detachment is proportional to the cubed flow velocity in general. Within the range where flow velocity is higher than 0.4 u(0) and less than 1.6 u(0) the detachment of soil particles has a probabilistic nature. The experimental data are described well by the equation formed from these premises. The third premise runs as follows: the detached soil particles, which move in the water Course of an overland flow as bed load and suspended sediment, in some way influence the detachment of new soil particles. The influence of natural and artificial bed load produced from different materials on wash out of chernozem samples are described satisfactorily by the exponential function. The suspended sediment corks up the pores of soil. Therefore it leads to a strengthening of the cohesion forces between soil particles and aggregates and consequently to a decrease of erodibility.