Determination of Suitable Landfill Site Using Geospatial Techniques and Multi-Criteria Decision Analysis: A Case Study of Nakuru Town, Kenya

The current system of selecting waste disposal sites in Kenya is manual, costly and time consuming. Computerizing the site selection process using Geographical Information System (GIS) can function as a decision support tool for improved efficient and effective municipal solid waste management. This studys aim was to develop landfill siting by employing GIS-based Multi-Criteria Decision Analysis (MCDA) such as Analytical Hierarchy Process (AHP) for evaluating the suitability for landfill site selection in Nakuru Town. The initial step of the methodology was GIS based operation and analysis that excluded all areas unsuitable for waste disposal facility. The selection of suitable criteria for landfill site selection were generated based on pre-existing information published on landfill criteria, existing environmental laws and regulatory requirements, as well as the prevailing local conditions. Seven suitability criteria are identified; geology, soil, land use, slope, surface waters, roads, and protected areas. Criteria were mapped using the GIS technique and spatial analytic tools, weights were determined by pairwise comparison matrix for the criterion maps and overlaid using GIS to create a landfill suitability map. Our results show that 62.8 % of the area was unsuitable for landfill siting; out of the remaining area, 5.52 % of the area was most suitable 11.24 % moderately suitable, 19.32 % suitable and 0.76 % poorly suitable.