Investigation of landfill suitability based on semi quantitative risk matrix and GIS

Open dumping is the most widely practiced method in Sri Lanka to dispose municipal solid waste (MSW) because it is the cheapest and easiest method compared to other methods available to manage MSW.Currently, there are no guidelines available for a proper selection of landfill dump site which may minimize the environmental, social and economic problems in the country. Site selection for landfill sites is an important aspect from both environmental conservation and social/economical point of view. Data was collected from the Udapalatha area for analyzing. Considering priority of all criteria in comparison with others, a specific risk rate was decided to each criterion according to their total influence on the whole process of decision making. Suitable landfill site was analyzed by using the Geographic Information System (GIS) together with risk assessment. To identify appropriate landfill areas in the study area, five input map layers including surface water bodies, distance from transportation routes, distance from urban areas, land use/land cover, and elevation were used in the mapping. Based on these data a risk assessment wascarried out with a semi-quantitative matrix. The findings obtained from this study could be used for preliminary information to develop criteria for new landfill site selection. Finally, suitable low-risk regions in the area have been proposed for solid waste landfill disposal