Abstract
At present landslide hazard assessment has given an important role in developing land utilization regulations aimed at minimizing the lives and damages of property. To assess the landslides, variety of approaches have been used in landslide assessments. They can be classified into qualitative and quantitative assessments. Walapane is one of the important social and economic area in Nuwara Eliya district. The landslides frequently occurred in this area, and it was seriously affected to the livelihood and lives. This area was selected due to the considerable amount of annual rainfall, the significance of the slope and yearly change of the land use. Therefore the problem was the landslide hazard and its prevention for a sustainable development of this area. The objective of this study is to prepare landslide hazards zonation map in Walapane. There were six data layers used in this study such as slope changes, annual rainfall variation, a variation of soil types, land use change, geology and the distance from the waterbodies. Then every factor was classified according to the features of each factor and the factor which had been affected by the landslide earlier. The classification was done according to the three risk classes called low risk, moderate risk, and high risk. Then all the vector maps were converted into raster format. For landslide susceptibility map, weight scheme was applied to the factors based on their importance for landslides. Analytic Hierarchy Process (AHP) was used to calculate the weight, the. Six data layers were overlaid considering weights of each factor. Then the landslide hazards zonation map was prepared. Landslide hazards zonation map was developed for November, December and January. According to the past landslide data, most of the landslides occurred in this period. Walapane was classified into three risk level in each month based on the final landslide hazard zonation maps (Table 1).
The map was validated using past landslide data. The overall accuracy of the hazard maps were November 68%; December 85% and January 63%.
