PREDICTION OF EROSION IN HILLY AREAS OF KHILAU SUB-SUB WATERSHED USING THE RUSLE METHOD

Abstract

Soil erosion poses an environmental threat to the sustainability and productivity of the land in the Khilau Sub-Sub Watershed, Bulok Sub-Watershed, Sekampung Watershed, Pesawaran Regency. The research aimed to predict soil erosion by implementing the RUSLE model on the Khilau Sub-Sub-Watershed, combined with remote sensing, GIS techniques, and field observation. This research is divided into several phases, i.e. soil data collection, getting satellite maps, obtaining rainfall data from 2011 to 2019, making the topographic maps of land slopes, land use, and soil types, whose overlay will be made, and data analysis. The results show that the areas with the highest risk of erosion were located on the hills and in the areas characterized by steep slopes of 1,395.48 (t/ha/year) with a slope level of >45% (very steep), which had the highest LS factor value and were characterized as areas with strong relief, i.e. hills (with a slope level of >20%). In conclusion, the erosion rate of the Khilau Sub-Sub Watershed is dominated by the erosion falling into the heavy category with an average erosion value of 405.17 (t/ha/year) by soil parameter, slope inclination, vegetation cover, and climate. The most influential factors in this study were the climate and slopes, where the lands used as mixed gardens and annuals had a high risk of erosion. So, it is of utmost importance to take soil protection and conservation measures for potential erosion protection in the area.