GIS based risk assessment of oil spill in the coastal areas of Akwa Ibom State, Nigeria

Assessing the total loss and damages that may result from oil spill constitutes risk assessment. The study area is the coastal Local Government Areas (LGAs) of Akwa Ibom State, located in the Niger Delta of Nigeria. The delta generates the greatest proportion of foreign exchange and internal revenue earnings of the country as the crude oil sector accounts for 90 to 95% of export revenues. Since most of information used for oil spill risk assessment have some form of spatial content, extensive use of Geographic Information System (GIS) capabilities are used in the study. A combination of hazard and vulnerability data layers constitutes the GIS based risk assessment. Hazard was modeled in the study by sources of petroleum oil spill moderated by surface characteristics, while data on crop suitability, socio-economy, environmental sensitivity, accessibility, and settlement development, were used to model vulnerability. The resulting risk layer was classed into four Risk zones of very high, high moderate and marginal risk. Iko and the environs were found to be in the very high risk zone. Based on the fact that increasing investments are being made in the petroleum oil sector in Akwa Ibom State, the study analysis the implications of the findings and stresses the need for a comprehensive GIS based oil spill contingency plan for the area.Key words: Risk assessment, vulnerability assessment, impedance surfaces, cost distance modeling