Assessment of Coastal Erosion Vulnerability in Lagos Island and Lekki Peninsula, South West Nigeria

Coastal erosion along the Lagos shoreline is accelerating, threatening urban infrastructure, ecosystems, and livelihoods. This study assessed coastal erosion vulnerability at selected sites along Lagos Island and Lekki Peninsula using a composite vulnerability index approach. Shoreline change rates over a twenty-year period were quantified using multi-temporal satellite imagery and digital shoreline analysis software. Physical vulnerability indicators including wave exposure, beach slope, shoreline change rate, sediment type, and relative sea level rise were scored and combined into a Coastal Vulnerability Index. Social vulnerability indicators including population density, infrastructure proximity, and adaptive capacity were incorporated into a composite assessment. Results showed that eleven kilometres of the Lekki Peninsula shoreline fell into the high to very high vulnerability category, with mean shoreline recession rates of 2.8 metres per year. Groyne structures and beach nourishment projects had temporarily slowed erosion at several sites but failed to address the underlying sediment deficit from reduced longshore sediment supply. High social vulnerability coincided with high physical vulnerability in densely populated informal settlements along the Lekki waterfront. The study recommends a comprehensive Integrated Coastal Zone Management plan for Lagos State incorporating dynamic setback zones, managed retreat strategies for highest-risk areas, and nature-based shoreline protection through beach restoration and dune stabilisation. Keywords: coastal erosion, vulnerability assessment, Lagos, shoreline change, coastal management.