Potential Landfill Site Selection in Gondar Town: A Decision Support System using GIS and Remote Sensing Technologies

Abstract

Selecting appropriate site for landfill is one of the major problems for most of towns and cities particularly in Ethiopia. This is due to the fact that the selection of suitable site requires the consideration of many environmental and socio economic variables. The study was initiated to map the potential suitable sites for solid waste landfill in Gondar town using GIS and remote sensing technologies. To achieve the objectives of the study GIS based multi criteria evaluation method was employed. To identify appropriate site for landfills 9 criterias were considered. All the input map layers were first georeferenced and converted in raster format to make them ready for reclassification. Afterwards they were reclassified based on their suitability level according to the standards set by different researchers and the prevailing local conditions of the study area. After reclassification weights for each criteria was assigned by following AHP procedures using pairewise comparison matrix. After assigning weights for each criterion they were combined together using weighted overlay tools and highly suitable areas were identified. The final suitability map shows that about 4.5% of the study areas were found to be highly suitable and 39.5% was unsuitable for landfill site. The identified highly suitable sites were then reevaluated using criteria like distance from the center of the city, distance from the nearby settlement and size of the area. To assign weights for each candidate landfills Analytical Hierarchy Process was employed and highly suitable sites among the 7 sites were identified. Accordingly Landfill site 7 which is found in south east part of the town and landfill site 3 found in the north west of the town were selected as the first and second most highly suitable sites for landfill respectively. These sites were selected because they are large in size and are found in a compromise distance from the city center as well as from residential areas. This study showed that GIS and remote sensing technology are efficient and cost effective to select suitable sites for landfill in an attempt to facilitate decision making process.