GIS-Based Multi-Criteria Assessment of Landfill Suitability in Awka South LGA, Anambra State, Nigeria

Abstract Municipal solid waste management requires suitable disposal locations that protect water resources and settlements while remaining accessible for waste collection and transport. This study assessed landfill suitability in Awka South Local Government Area (LGA), Anambra State, Nigeria, by integrating Geographic Information Systems (GIS), the Analytic Hierarchy Process (AHP), and a weighted linear combination (WLC). Seven criteria were evaluated: land use/land cover (LULC), slope, elevation, geology, soil, distance from drainage networks, and distance from roads. Criteria were standardized to a three-level suitability scale and weighted through pairwise comparison. LULC received the highest weight (0.27), followed by slope (0.20), elevation (0.16), geology (0.13), soil (0.10), drainage proximity (0.07), and road proximity (0.06). The consistency ratio was 0.046. The resulting suitability map classified 110.60 km² as low suitability, 42.01 km² as moderate suitability, and 2.50 km² as high suitability. Overlay with four existing waste-fill locations placed Agu Awka in the high-suitability zone and Ifite, Amawbia, and Okpuno in the moderate-suitability zone. The results identify a limited area with the most favourable combination of land-cover, terrain, geological, soil, hydrological, and access conditions. The GIS-AHP framework provides a spatial planning basis for comparing candidate locations and supporting improved solid waste management in Awka South. Keywords: landfill siting; geographic information systems; analytic hierarchy process; weighted linear combination; multi-criteria decision analysis; Awka South; Nigeria