Optimizing Landfill Siting in Pokhara Metropolitan City Using Gis-Based Multi-Criteria Decision Analysis

Pokhara Metropolitan City has seen a rapid expansion of the urban footprint, and population growth has resulted in an increase in municipal solid waste that far exceeds the capacity for disposal and management. This study utilized a GIS-based Multi-Criteria Decision Analysis (MCDA) approach using the Analytic Hierarchy Process (AHP) to determine the best locations for landfill sites. The study selected eight criteria and assigned weights to the criteria based on the relative importance to determine landfill suitability: proximity to lakes, rivers, roads, and settlements, slope, soil type, land use/land cover (LULC) type, and tourism areas. An assigning weight and combining analysis was performed in ArcGIS in which spatial layers were reclassified for analysis using weighted overlay analysis. The final product was a suitable map of land represented in four classes: unsuitable, less suitable, suitable, and highly suitable. The study results demonstrate that only 5.2% of the total area is very suitable for landfill development and that the highest consolidated amounts of land designated as highly suitable were in the north and east wards. Field verification showed that the GIS-based model is reliable, and the process is transparent and replicable. The methodology used in this study is important for sustainable landfill siting in urban planning, and the method has wider applications for similar areas in the Himalaya region undergoing rapid urbanization.