Inferring potential landslide damming using slope stability, geomorphic constraints and run-out analysis; case study from the NW Himalaya

Abstract. Prediction of potential landslide damming has been a difficult process owing to uncertainties related to landslide volume, resultant dam volume, entrainment, valley configuration, river discharge, material composition, friction, and turbulence associated with the material. In this study instability pattern of landslides, parametric uncertainty, geomorphic indices, post-failure run-out predictions, and spatio-temporal pattern of rainfall and earthquake is explored using Satluj valley, North-West (NW) Himalaya as a case study area to predict the potential landslide damming sites. The study area witnessed landslide damming in the past and incurred $ ~ 30 M loss and 350 lives in the last four decades due to such processes. Forty-four active landslides in the study area that cover a total ~ 4.81 ± 0.05 × 106 m2 area and ~ 34.1 ± 9.2 × 106 m3 volume are evaluated in the study to identify those that may result in potential landslide damming. Out of forty-four, five landslides covering the volume of ~ 26.3 ± 6.7 × 106 m3 are observed to form potential landslide dams. Spatio-temporal varying patterns of rainfall in recent years enhance the possibility of landslide triggering and hence potential damming. These landslides also resulted in 24.8 ± 2.7 m to 39.8 ± 4.0 m high material flow in run-out predictions.