GIS-Based Suitability Analysis of Landfill Sites in Davao City, Philippines

Abstract. The continued rise in solid waste generation in Davao City has placed significant pressure on its existing landfill infrastructure, with the lone operational facility in New Carmen reaching full capacity. Existing studies have highlighted the advantages of using Geographic Information Systems (GIS) in site suitability analysis, owing to their capacity to integrate multiple spatial factors and provide evidence-based decision support; this method can be useful for identifying a new landfill location. In response, this study investigates the spatial suitability of current, proposed, and alternative landfill locations through a GIS-based multi-criteria method grounded in the standards set by the DENR-NSWMC Resolution No. 64, Series of 2013. Spatial datasets corresponding to environmental, geological, infrastructural, and regulatory criteria were evaluated through a weighted overlay analysis, with priority coefficients of parameters derived from expert-based pairwise comparisons under the Analytical Hierarchy Process framework. The assessment revealed that both the existing and the proposed adjacent landfill locations generally fall within the “less suitable” classification, failing to meet several critical spatial and environmental thresholds. In contrast, a previously unconsidered site located in Barangays Callawa and Riverside met all key suitability conditions, including the minimum required area, and demonstrated full regulatory compliance to all parameters. This study underscores the importance of evidence-based spatial planning in addressing urban waste challenges and offers a replicable framework for identifying sustainable landfill locations in rapidly growing cities.