Landslide Hazard Susceptibility Analysis and Modelling in the Vicinity of the Proposed Subansiri Lower HE Project, Arunachal Pradesh

The Himalayan region of India, in particular, faces an escalating slope instability due to landslides, posing significant pressure on rapid developmental activities. In this chapter, the study focuses on generating a comprehensive landslide susceptibility map (LSM) to analyze and detect the most crucial zones susceptible to landslides for the biggest hydroelectric project undertaken in India- Subansiri lower hydroelectric project situated on the intensive slopes of the Himalaya which is under a constant threat of recurring landslides utilizing a Geographical Information System (GIS) based Analytical Hierarchy Process (AHP) model. The LSM was created by considering a range of 9 geo-environmental parameters like slope, aspect, lithology, lineament density, geomorphology, drainage density, NDVI, LULC, and Road (Euclidean distance) to identify areas susceptible to future landslides and to delineate potential hazard zones. Using the Receiver Operating Characteristic (ROC) curve model, the AHP model was validated and yielded accuracy rates of 79.2%, 79.8%, and 79.2% for the geometrical-interval, quantile, and natural breaks (Jenks) classification models, respectively. A predictive numerical rockfall model Rapid Mass Movement Simulation (RAMMS) was employed to detect the runout trajectories and spatial extent of rockfall around the vicinity of the dam. The velocity of the estimated future rockfall was detected to be 9.84 ms−1, Jump height of 1 m, and kinetic energy of 132.80 kJ. The study’s outcomes hold practical implications for infrastructure development and management in landslide-prone regions, as the susceptibility map can aid in the implementation of effective risk mitigation strategies.