Landslide Hazard Zonation of Tehri Reservoir Rim Area Using Modified LHEF Rating Scheme

Abstract

The study aimed to utilize the capabilities of geospatial technology for landslide hazard evaluation factor (LHEF) scheme recorded in the Bureau of Indian Standard (BIS) code to prepare a landslide hazard zonation (LHZ) map of the Tehri reservoir rim area at the macro-scale. Multisource remote sensing data were visually and digitally interpreted to produces thematic layers and slope facet as recorded in BIS method. LHEF method is suited for meso and macro scale mapping thus, to broaden the scope of LHEF scheme, novel approaches were adopted namely, the mapping unit ‘slope facet’ was more precisely extracted through digital and visual interpretation of remote sensing data, the structural favorability map was extracted using photo-lineament density criteria. Additionally, two external factors, rainfall and seismicity were incorporated in LHEF rating scheme and used a matrix-based system to propose their combined rating. With the modified LHEF rating scheme, we have succeeded in identifying LHZ with reasonable accuracy. The bar chart method used to validate LHZ results that clearly indicated a high number of landslides falling in high to very high hazard zone conversely, very few landslides observed in low to very low hazard zone identified from current approach.