Ecological Risk Assessment of Oil Spill Events Using a Coupled Geospatial and Weight of Evidence Data-Process Model

Abstract

This research work applied geospatial and weight of evidence approach to ecological risk assessment for quantifying environmental exposure to oil pollution in the Niger Delta. Spatial data for Pipelines, Oil spills and Land Cover were used to quantify the extent of Ecological resources exposed to oil pollution using a data-process model. Regional scale risk assessment was done using the combination of geospatial and statistical approaches. Hotspot and Proximity analysis were used for geospatial analysis while weight of evidence was adopted for statistical computation. Ecological resources were identified from land cover maps and ranked according to their perceived importance. Hotspots of oil spill incidents were determined using spatial autocorrelation. Ecological resource vulnerability was determined using buffer zoning of 5 km and 10 km respectively as high and low risk zones, with sample maps made to show extents of resources at risk. Areal extent of ecological resources at risk were calculated and standardized for each of the delineated buffer zones. An aggregate of the weight of each ecological resources and area was computed to categorize the risk as either high, medium or low. This study has successfully assembled and produced relevant spatial and attribute data sets and applied integrated geostatistical analytical techniques to understand the distribution and impacts of oil spills in the Niger Delta. The procedure was seen as an alternative to existing management processes used for monitoring and management of oil spill events.