A Geo-Spatial multi-criteria evaluation approach for solid waste landfill site selection in Gampaha, Sri Lanka

Abstract

Solid waste management has become one of the most critical and challenging issues worldwide, and Sri Lanka is no exception. In Sri Lanka, the municipal solid waste production is estimated to be 7,500 metric tons per day, and a person generates 0.4 to 1.0 kg of waste per day [1]. As a result, a significant amount of waste that has not been collected is being openly disposed of, burnt, or disposed of illegally, thus contributing to environmental pollution, ecological degradation, and increasing health risks. The aim of this study is to select suitable waste landfill sites for the country’s rapidly urbanizing Gampaha district, in the Western Province. Remote Sensing and Geographic Information Systems (GIS) play an important role in spatial decision-making for waste management, as they allow comprehensive analysis of diverse environmental, social, and infrastructural data layers over large geographic extents. These tools provide a systematic approach to the assessment of site suitability when combined with Multi-Criteria Decision Analysis (MCDA). The Analytical Hierarchy Process (AHP) method is widely applied due to its ability to assign weights to criteria through pairwise comparisons, reflecting expert judgment. This integration of RS, GIS, and AHP-based MCDA has been successfully used in landfill site selection studies worldwide, and it offers a systematic and transparent approach for identifying suitable waste landfill sites in Gampaha District.