Equations and evaluations of sediment carrying capacity of overland flows

Estimating sediment carrying capacity of overland flow is the key point in soil erosion process and it is also the criterion to decide whether erosion or deposition happens.The existing sediment carrying capacity equations are summarized and evaluated by using the laboratory data.Results show that Low and Abrahams equations can give good predictions without rainfall impact.Although the rainfall impact is considered,Shih equation performs well only under special hydraulic conditions.Guy equation separates the portion of sediment carrying capacity due to flowing water from that due to rainfall impact.New parameters of Guy equation are obtained through calibration and better predictions of sediment carrying capacity are given.The criterion of critical Shields number for sediment inception is not applicable for overland flows under rainfall impact.