Comparison of Various Rainfall Erosivity Formulas in the Application of USLE for Erosion Cases in Indonesia

Abstract

Erosion is a complex process that results in the movement of soil particles from one place to another through a series of processes of detachment, entrainment, transport, and deposition. Erosion can cause serious environmental problems, such as loss of soil fertility, and sedimentation of rivers, lakes, and reservoirs. Therefore, it is important to identify and mitigate erosion problems in the management of a watershed. The erosion prediction model that is popularly used, especially in Indonesia, is the Universal Soil Loss Equation (USLE). One of the parameters in the USLE formula is the rainfall erosivity factor (R). Many formulas have been developed to calculate the R-factor. However, not all formulas are suitable for application in Indonesia. In this study, a comparison of several R formulas from various countries in the Asia Region was carried out. From the results of the comparison, it was found that for Riam Kanan Sub-watershed, the appropriate formula for rainfall erosivity is the Merritt et al. (2003) formula, while for Brantas Sub-watershed erosivity formulas from Utomo (1994) and Babu et al. (2004) is the most suitable. The results of this study can be used as a consideration in determining the appropriate rainfall erosivity formula (R) for a particular case.