Evaluation of Rainfall-Runoff Erosivity Factors for Individual Storms

THE Universal Soil-Loss Equation is widely used to satisfactorily estimate average annual soil loss from rainfall. Without modification, it is somewhat unsatis-factory for estimating soil loss from individual storms. Several erosivity factors that could be used to estimate soil loss from individual storms were investigated in this study. Rainfall erosivity factors like EI30 that include both rainfall rate and amount terms were found to be much better predictors of soil loss than a factor including rainfall amount alone. Lumped erosivity factors that in-clude rainfall amount, rainfall intensity, and runoff amount were even better predictors than EI30, whereas erosivity factors with separate terms for rainfall and runoff erosivity were best. However, these factors did not greatly improve soil loss predictions as compared with EI30.