A New Method of Determinin Rainfall Erosivity in the Hilly Area of Southwestern China

摘要

Rainfall erosivity (R) is one of the key factors involved in the soil loss prediction equation that should be determined in a rational and simple way. Analysis of the erosion data of plots and rainfall data in the hilly area of Sichuan Basin. China revealed that the critical value of erosive rainfall is 14mm and the erosive intensity of rainfall is 1.5 mm·h-1. An average of 82% rainfall events could be eliminated with only 8.8% relative error using the critical value of erosive rainfall. The best characteristics of rainfall for calculating the rainfall erosivity were found to be the product (PIa) of rainfall (P,mm) and the average rainfall intensity (Ia, mm/h). The following novel equation of rainfall erosivity (Rn) was developed based on (PIa): Rn=66.22+2.98PIa. This model was also tested and found to be effective for the study area. Therefore, the equation developed here is a feasible and simple method for calculating the rainfall erosivity in the central hilly area of Sichuan,China.