Assessment of Coastal Erosion Trends Along the Badagry Coastline, Lagos State

Coastal erosion along Nigeria's Atlantic coastline threatens critical infrastructure, settlements, and ecosystems, with the Badagry coast among the most actively eroding segments in Lagos State. This study assesses shoreline change trends along a 45-kilometre stretch of the Badagry coastline using multi-temporal satellite imagery and historical topographic maps spanning 2010 to 2024. Digital shoreline analysis was conducted using the Digital Shoreline Analysis System extension within ArcGIS, computing end-point rate and linear regression rate statistics for 87 transect lines. Field surveys documented erosion indicators including scarped beaches, undermined structures, and displaced sand fences. Community interviews with 90 coastal residents captured local observations and displacement histories. Findings indicate a mean shoreline retreat rate of 3.6 metres per year, with hotspot areas around Agbara and Ajido recording retreat exceeding seven metres annually. Wave energy concentration at coastal promontories, dredging activities in adjacent waterways, and destruction of nearshore vegetation are identified as primary drivers. Forty-two residential and commercial structures have been lost to erosion within the study period according to household accounts. The study recommends coastal setback zone enforcement, beach nourishment as a medium-term intervention, and restoration of mangrove and coastal vegetation belts as natural erosion buffers. Keywords: coastal erosion, shoreline change, Badagry, Lagos State, coastal management.