Mapping Oil Spill Extents in Ogoniland Using Sentinel-1 SAR Imagery

The Ogoniland area of Rivers State has been subjected to chronic oil contamination from pipeline leaks and sabotage, severely degrading terrestrial and aquatic ecosystems. This study maps recent oil spill extents in Ogoniland using Sentinel-1 Synthetic Aperture Radar imagery acquired between 2020 and 2023. Oil spills on water bodies are detected using the dark spot anomaly method, which exploits the dampening of radar backscatter by oil films on water surfaces. Terrestrial spill areas are delineated by integrating SAR data with optical imagery from Sentinel-2 to detect vegetation stress through the Red Edge Chlorophyll Index. A total of 23 distinct spill events are mapped, covering a combined area of approximately 4,700 hectares. Results are cross-referenced with incident reports from the National Oil Spill Detection and Response Agency to validate detection accuracy. The study documents persistent contamination sites that predate the United Nations Environment Programme Ogoniland assessment and remain unaddressed. Keywords: oil spill, SAR, Ogoniland, Sentinel-1, contamination mapping