Artisanal fisheries in the Niger Delta and Nigeria’s coastal waters support the livelihood of its inhabitants, thus management of water pollution has public health significance for the regions and beyond. Oil Spills and contaminated runoff from the hinterland always find their way to the coast via the extensive network of rivers and creeks across the delta. This is a major cause of marine pollution in the region. With this understanding there is a need to map and model the dynamics of oil pollution across the coastal waters of the Niger Delta, thereby providing evidence and data support for their management. This study explored the potential of mapping oil slicks along the inland and coastal water of the Niger Delta using the SENTINEL-1 Synthetic Aperture Radar (SAR). The Interferometric Wide Swath Mode imagery Ground Range Detected Imagery for the 2nd of January 2019 was acquired for the study area, processed using Sentinel Application Platform (SNAP) and the oil spill detection algorithm was applied on the Amplitude Vertical-Vertical Band. After preprocessing, the non-polluted areas were found to have high backscatter (amplitude >18.0). For the impacted areas, lower values were recorded – amplitude decibel value of between 15.9 and 18.0. A total of 329 polygons of oil slick were identified, covering an area of 46.34 km2. The impacted surface area ranges between 0.000064 – 15 km2. The farthest impacted surface can be found around 18.25km from the Bonny coastline. Results showed that a significant proportion of the oil slicks are concentrated along the upper reaches of the Bonny River spanning Okrika and Ogu/Bolo LGA. Towards the nearshore, the oil slicks were disaggregated into several units. Contiguous units were found closer to the banks and coastline. Out of the 329 polygons, 14 were identified along the New Calabar River, emptying into the Bonny Estuary. The impacted surfaces along the New Calabar River were smaller in size compared to those found along the Bonny River. The results identified the pattern and distribution of oil slicks across a segment of the Gulf of Guinea dominated by oil and gas industry activities. This study highlighted the potential of remotely sensed data to support coastal pollution management efforts. It further highlighted the potential for spatiotemporal monitoring of oil slicks along coastal and inland waters. Challenges for deploying such a platform include the high computing power required and the lack of in-situ monitoring data for validation.
Keywords: Inland Waters, Modelling, Oil Pollution, Synthetic Aperture Radar, coastal waters
