The Identification of Landslide Risk-Prone Areas in the Imbulpe Divisional Secretariat in Sri Lanka: A GIS-Based Multi-Criteria Decision Analysis

Abstract

Landslides can be identified as a prominent natural hazard that causes significant loss of life and property damage in many parts of the world and Sri Lanka. Planning experts, local governments, and decision-makers can benefit greatly from the identification of landslides and the creation of landslide susceptibility maps. Accurate landslide susceptibility maps are essential to minimize the loss of life and property. The landslide risk zones in any area can be plotted using GIS-based MCDA techniques that integrate the Analytic Hierarchy Process (AHP) and Weighted Linear Combination (WLC) functions in ArcMap. This study attempted to develop a multi-criteria decision analysis for the appraisal of landslide risk zones in the Imbulpe DSD in Rathnapura District. To analyze the danger of landslides, MCDA was used in conjunction with GIS as a spatial decision-making tool. Slope, drainage pattern, soil type, geology, land use, and rainfall pattern were the six factors used in the study. Landslide risk maps were produced based on weighted techniques such as Analytic Hierarchy Process and Weighted Linear Combination. The slope area significantly affects the likelihood of a landslide. Results revealed that landslides were spreading in a manner that extended toward the eastern section of the study area. Because there are no good locations to build houses in the study area, a huge number of individuals tend to live in unprotected areas. The majority of the landslides in the area occurred during May, October, and November because those months received heavy rainfall. As remedial actions, it can be proposed to displace people living under landslide risk in the northeast and northwest slope areas to suitable protected areas.