SCS-CN-based modeling of sediment yield

Coupling the soil conservation service curve number (SCN-CN) method with the universal soil loss equation (USLE), a new model is proposed for the estimation of the rainstorm-generated sediment yield from a watershed. The coupling is based on three hypotheses: (1) the runoff coefficient is equal to the degree of saturation, (2) the potential maximum retention can be expressed in terms of the USLE parameters, and (3) the sediment delivery ratio is equal to the runoff coefficient. The proposed sediment yield model is applied to a large set of rainfall-runoff-sediment yield data (98 storm events) obtained from 12 watersheds of different land uses (urban, agricultural, and forest). For all watersheds the computed sediment yield is found to be in good agreement with the observed values. The results and analysis of model application show that the model has considerable potential in field.