Effect of slope steepness parameter computations on soil loss estimation: review of methods using GIS

AbstractIn the analysis of soil loss equation, the researchers have suggested two methods of deriving the slope steepness parameter. One method is having percentage slope term, while the other method is having sinθ as its term. In this paper, both the methods were analysed and compared in soil loss computation using Revised Universal Soil Loss Equation, over a Gangapur catchment area in India, having steep slopes. The soil loss rates derived were 0.98 million tonnes per year in case of steepness parameter derived by sinθ and 1.226 million tonnes per year in case of steepness parameter derived by percentage slope term. The observed rate of soil loss is 1.23 million tonnes per year. This methodology of soil loss estimation was also validated with similar catchment of Punegaon dam. It is concluded that for medium to steep terrain, percentage slope method estimates more accurate soil loss than other empirical methods for slope steepness estimation.