Identifying potential landfill sites using GIS and Analytic Hierarchy Process in Hawassa City, Ethiopia

Municipal solid wastes are heterogeneous trash materials that arise from both human and animal activities. Ethiopian cities, with limited or no access to suitable solid waste disposal sites, are facing heightened environmental, economic and public health risks due to such wastes. The main objective of the present study was to identify and map suitable landfill sites in the Hawassa city by integrating Geographical Information System (GIS), Remote Sensing and Analytic Hierarchy Process (AHP) methods to contribute to the citizens’ welfare. The process involved generation of eleven factor maps in a GIS environment to achieve the set objectives. The classification of a satellite image generated eight Land Use Land Cover (LULC) classes using Erdas Imagine where built-up area (3014 ha), swamp (2624 ha), and Lake (9501 ha) that were used as factors in disposal site selection. The relative weights of factor maps were determined using pairwise comparison matrix analysis. Based on the results, groundwater well with 23.96% weight was identified as the most influential factor followed by built-up area, while elevation weighting 1.44% appeared the least. The result of weighted overlay analysis revealed that 24804.90 ha (91.7%), 46.57 ha (0.17%), 824.81 ha (3.12%), 1351.06 ha (4.99%), and 4.26 ha (0.02%) of the study areas fall under unsuitable, less suitable, moderately suitable; suitable and highly suitable land for disposal site, respectively. From the identified moderately suitable, suitable and highly suitable sites, areas potentially suitable based on spatial criteria were located in the northeastern, sub-central and southern part of the study area. Besides, the identified suitable sites were checked for their surface area size to be ≥ 10 ha to increase the service life of the identified landfills. Finally, the identified spatially suitable candidate areas for solid waste disposal sites are expected to provide valuable inputs for decision makers and ultimately promote environmentally friendly urban setting and contribute to the Sustainable Development Goals.