Need and Urgency of Landslide Risk Planning for Nilgiri District, Tamil Nadu State, India

Landslide is one of the major natural hazards that are commonly experienced in hilly terrains all over the world. Landslides are affect at least 15 per cent of the land area of Indian area which exceeds 0.49 million km². In India the incidence of landslides in Himalayas and other hill ranges is an annual and recurring phenomenon. There is a variation in the degree of landslide incidences in various hill ranges. For example, the landslide incidences are high to very high in Himalayas, high in Northeastern hill ranges, high to moderatein Western Ghats & Nilgiris and low in the hill ranges of Eastern Ghats & Vindhyas. The landslide hazard zonation atlas of India published by Building Materials and Technology Promotion Council (BMTPC), Government of India reveals that the Nilgiris district of Tamil Nadu state is one of the severe to very high landslide hazard prone areas of India.

Unprecedented rains triggered about a hundred landslides within an area of 250sq.kms in the district during 1978. Nearly 200 landslides were recorded during 1979 and causing loss of life and severe damage to property. Though the Nilgiri and other mountainous areas are known to be susceptible to landslides, occurrences of such magnitude were unknown earlier. A total of 28 landslides of medium to large size occurred on 14 November, 2006 along NH67 between Kallar and Pudukkadu villages and along Mountain Railway track between Adderley and Barliyar stations. In the recent times casualities and damage due to landslides have increased in the Nilgiri Hills. More than 110 landslides were reported within five days from 10 to 15 November, 2009, and taken away about 80 human lives, also the vast damage reported on houses, roads and railway lines. This taught the lesson for the need and urgency of landslide planning in Nlgiris among the scientific community and planners.