Determining Suitable Sites for Large-Scale Petrochemical Industry in South Eastern Nigeria Using GIS-Based Multicriteria Analysis

Site selection is one of the most important choices in the start-up, expansion, or relocation of any business. Construction of a new industrial system is a significant long-term investment, and identifying the site is a vital step on the path to the success or failure of the industrial system. Site suitability assessment in Southeast Nigeria, like elsewhere, is influenced by inherent conflicts and a complex network of socioeconomic and ecological constraints, necessitating the use of a flexible decision-making support tool capable of incorporating multiple evaluation criteria, including the perspectives of various decision-makers. In this study, a GIS-based multi-criteria approach was used for site suitability evaluation for the large-scale petrochemical industry in Southeast Nigeria. The objectives of the study include reviewing planning concepts and existing planning guidelines for the siting petrochemical industry, defining important factors and criteria needed for the establishment of the industry in the area, determining potential locations for the proposed industry through the combination of these factors, while considering constraints, using multi-criteria analysis and produce maps showing suitable sites. Datasets used for the study comprised satellite images for land use, SRTM, climate data, geology, soil, rainfall and disaster risk. The methodological approach enabled the evaluation of relative priorities of locating sites for the petrochemical industry, based on a set of criteria such as physiography, land slope, distance to river, soil type, rainfall, climate, land use land cover, distance to geological structures, land systems and geomorphology, distance from settlement, accessibility, distance from Central Business District (CBD), and disaster risk. Analytical Hierarchical Processes (AHP) were used in comparing criteria through matrix comparison and derive relative weights of the criteria. The weighted overlay was used to integrate suitability criteria maps to derive the final suitability map. An iterative post-aggregation constraint was applied ·to identify potential sites as a basis for delineating potential areas for the petrochemical industry. The final suitability map showed that 31% of the region was unsuitable for such industries due to the presence of developed areas such as built-ups, and residential and commercial areas. However, 35% of the region had less suitability while about 9% was highly suitable. In general, all the states in the southeastern region had high potential for large-scale petrochemical industries as 37 out of 95 local government areas in the region had highly suitable locations. It was recommended that demographic and environmental impact assessment be implemented in order to ensure suitable or potential sites would be effective and resourceful for the people, communities, and the region at large. In this way, industries can exist with less harmful impact on the environment while promoting economic growth and sustainability.