Identification of Optimum Route Alignment in LS areas Using GIS & RS

Sri Lanka receives a high intensity of rainfall all over the year especially from the two monsoon periods and two inter monsoon periods. According to the geological structure of the country, rainfall pattern has been directly influenced the occurrence of landslide that is one of most recorded natural disasters in Sri Lanka. Road network especially in hilly terrain is affected by landslide in every rainy season. Therefore, the maintenance cost of the Road Development Authority is increasing and roads have to be closed for traffic due to landslides. Hence developing a methodology to identify an optimum route alignment in landslide areas is essential in the planning of roads. To identify the optimum route alignment for Beragala-Koslanda landslide area, geo-informatics approach was used considering engineering factors simultaneously in the present study. 1:10,000 scale topographic map, 30m resolution downloaded USGS DEM, 1:100,000 geology map and 1:50,000 landslide hazard zone map were used as basic input data for the analysis.