Estimating the r-factor with limited rainfall data: A case study from Penisular Malaysia

Abstract

Lack of long term, continuous pluviograph data makes it difficult to determine the R-factor for the Revised Universal Soil Loss Equation (RUSLE) in many parts of the work Limited pluviograph data and long term daily rainfall data for two sites in Peninsular Malaysia were used to evaluate a daily rainfall erosivity model and estimate the R-factor and its monthly distribution. Mean annual rainfall for the two sites ranged from 1880-3070 mm, and the R-factor ranged from 13,60-21,600 MJ mm ha-1 hr-1 yr-1. A model using daily rainfall data to estimate monthly EI30 performed well with the coefficient of efficiency in excess of 0.87 and a mean discrepancy of less than 2% in the monthly distribution of rainfall erosivity. The rainfall erosivity model can be used to accurately estimate the R-factor and its seasonal distribution with long term daily rainfall data which are available in Malaysia, and elsewhere in the world.