Morphometric Control and Basins Response to Slope Failures -A Case Study along the Mughal Road, Pir Panjal Range, Northwestern Himalaya

ABSTRACT The Mughal Road, traversing the Pir Panjal Range of the northwestern Himalaya, is recurrently affected by slope failures that disrupt connectivity and pose significant hazards. This study examines the morphometric controls and basin-scale response to slope instability within selected catchments intersecting the road corridor. Morphometric parameters were extracted from highresolution DEMs and topographic datasets, including linear, areal and relief aspects, to prioritise the watersheds based on the erosion potential as well as mass wasting processes. Spatial analysis reveals that basins having higher values of bifurcation ratio, mean stream length ratio, and lower values of form factor are sensitive to the ongoing erosion and mass movement processes. The study reveals that the linear parameters have a direct relationship with run-off and erodibility, i.e. higher the values more the erodibility. On the contrary, shape parameters have an inverse relation with run-off and erodibility, i.e. lower the values more is the erodibility. Additionally, the relief parameters also have a direct relationship with surface run-off and erodibility. The findings underscore the influence of morphometric configuration on the initiation and propagation of slope failures, offering critical implications for hazard assessment, geomorphic risk zoning, and sustainable infrastructure management in highaltitude mountainous terrain. The study further demonstrates that the basin slope is considered the most fitting and prevailing parameter for the assessment of slope instability. A simple linear regression approach, i.e. FLAA = 1.315, BS - 0.114, was developed for the assessment of Fractional Landslide Affected Area (FLAA) along the Mughal Road. The correlation of FLAA and Basin Slope (BS) suggests that BS, in association with other effective morphometric parameters, played a major role in destabilising slopes in the study area.