Assessment of Soil Loss Using GIS and RUSLE Model in Bakiya River Basin (BRB), Central Nepal

Soil erosion is the major geological hazard in the fragile landscape of Sub-Himalaya. This study examines the susceptibility of the Bakiya River Basin (BRB) in Central Nepal to soil erosion because of its steep topography, fragile geology, the impact of intense monsoon rainfall, and the lack of a direct monitoring mechanism available for rainfall-runoff. This study examines the spatial variations of soil erosion across the basin with the integration of the Revised Universal Soil Loss Equation (RUSLE), Remote Sensing (RS), and Geographic Information System (GIS). The findings identified the areas vulnerable to soil erosion, which are primarily influenced by the topography. The erosion rates in BRB vary from 0 to 729.6 t.ha^-1.yr^-1, with an average erosion rate of 41 t.ha^-1.yr^-1. Furthermore, about 65% of the total area needs immediate conservation action, which exceeds the threshold of 25 t.ha^-1.yr^-1. Model validation using the ROC curve yielded an AUC value of 0.827 which indicates a "Good" accuracy classification for the erosion estimates. The study's findings provide valuable information for conservation planning. They could prove valuable for the proposed and ongoing critical projects such as the Kathmandu Terai Fast Track (KTFT) and Nijgadh International Airport. Erosion control in the BRB is critical for the productivity of soil and environmental protection, as well as for minimizing downstream impacts such as sedimentation, flooding, and soil degradation. This study emphasizes the importance of sustainable management approaches in preserving the basin's soil and economic feasibility.