ANALYZING THE IMPACT OF LANDUSE ON EROSION RATES ON THE CAPACITY OF SABO DAMS

Abstract

Landuse changes in the Bangga Watershed, Sigi Regency, Central Sulawesi, have become the main factor increasing erosion and sedimentation threatening the capacity of Sabo Dam, This study aims to analyze the effect of landuse change on erosion and sedimentation rates and evaluate the Sabo Dam's capacity to reduce sediment, The method used is a quantitative approach using the Universal Soil Loss Equation (USLE) model to calculate erosion rates and the USDA Sediment Delivery Ratio (SDR) method to estimate sediment transport, Analyzes were conducted on landuse data for the 2013–2025 period, rainfall, soil types, and slope gradients using Geographic Information Systems (GIS), The results show that the conversion of 912,99 Ha of secondary forest into shifting cultivation areas exponentially increases erosion, especially on steep slopes (>45%) with erosion values reaching 4,224 Ton/a/Year, The highest erosion occurred in 2019 after the flash flood, reaching 106,532,60 Ton/Ha/Year, The Sabo Dam with a capacity of 8,500,000 m³ is still able to accommodate the highest total sediment (8,176,943,79 m³) with a remaining capacity of 323,056,21 m³, Operation and maintenance of the Sabo Dam must be carried out annually to ensure optimal sediment control function, Policy recommendations include restricting secondary forest conversion on steep slopes and critical land rehabilitation programs covering 379,79 Ha,