Spatial Integration of Rainfall and Runoff Kinetic Energy for Soil Erosion Prediction in the Pandanduri Reservoir Catchment Area, Indonesia

Abstract

The main problem that occurs in the Water Catchment Area is soil erosion. The results of soil erosion can cause increased sedimentation, which ultimately reduces the capacity of the reservoir. Several erosion approach models, such as USLE, generally emphasize rainfall as a factor of soil detachment, while surface runoff as a sediment carrier has not been explicitly integrated into spatial analysis. This study aims to integrate rain kinetic energy and runoff kinetic energy in predicting soil erosion in the Pandanduri Reservoir Catchment Area by incorporating both energies based on runoff occurrence land units (SLKL). The data needed in this study include rainfall data, DEM, soil type maps, and land cover maps. Rain kinetic energy is calculated as a temporal controlling factor, and runoff kinetic energy is derived from slope and flow accumulation factors. The analysis results identified 30 land units, 84 runoff units, and 235 runoff occurrence land units. The calculation results show that the erosion rate ranges from 0.02–8.90 tons/ha/year. Runoff kinetic energy exhibits significant spatial variation and strongly influences the rate of soil erosion. The integration of rainfall kinetic energy and runoff kinetic energy provides a more realistic erosion prediction and can be used as a basis for determining conservation priorities in the Pandanduri Reservoir Catchment Area.