Macro Landslide Hazard Zonation Mapping - Case Study from Bodi – Bodimettu Ghats Section, Theni District, Tamil Nadu - India

Abstract

Landslide is a common natural hazard that usually occurs in mountainous areas. Rapid urban development and high traffic intensity movements have been hampered to a great extent by phenomenon of landslides. In Ghat section, vertical cuttings and steep slopes are induced slope failures. An assessment of landslide hazards is therefore a prerequisite for sustainable development of the hilly region. In the present study, Macro Landslide Hazard Zonation was carried out in the Bodi – Bodimettu ghats section, Western Ghats, Theni district. The slope spreads over an area of about 10.09 sq km encompassing Puliuttu Ar. sub-watershed. The study was made with help of different types of data including Survey of India topographic map, geology map, important inherent factors like lithology, structure, slope morphometry, relative relief, land use/land cover and hydrogeological conditions using Bureau of Indian Standard (BSI 14496 (Part 2):1998) and related thematic maps. Based on the thematic layers, landslide hazard evaluation factor (LHEF) and total estimated hazard (TEHD) were calculated and the macro hazard zonation map was prepared. Landslide Hazard Zonation (LHZ) of the terrain shows that out of 17 facets, facets 1 to 5 and 8 falls under Moderate Hazard zone category and facets 6, 7 and 9 to 17 under the High Hazard zone category. The field study with further analysis for hazard concluded that about 68% of the total area falls in the high hazard zone.