Assessment of denudation rate and erosion susceptibility in the upper Tamakoshi basin in the higher Himalayas, Nepal

The higher rate of slope erosion in the Himalayan basins is contributing to rapid change landform mountainous terrain, which has caused sedimentation, and inundation downstream. Tamakoshi basin a trans-boundary river that originates from Tibet flows through Dolakha Ramechap districts before joining Sapta Koshi river. Few studies exist Nepal attempting quantify susceptibility. However, they are scattered mainly focus on either rill-sheet or landslide only. Hence, this study attempted estimate by applying Revised Universal Soil Loss Equation (RUSLE), soil debris (2000-2019). Spatially distributed intensity maps derived RUSLE model, as well index-based susceptibility map, were integrated capture both running water gravity processes. novelty research it examined using process-based model rock displaced observed landslides over last 20 years. estimated gross annual 9.1million tons/yr, equivalent denudation 3.34 mm/yr. Of these, accounts for 7.6 million ton/yr, i.e., 2.88 mm/yr, covers about 84% total erosion. High potential areas associated with high rainfall, steep slopes, scarps, lower segment valley side relief, highly fractured deformed parts high-grade metamorphic rocks, such gneiss, quartzite, marbles, migmatite, granitic gneiss.