Coastal Erosion Assessment Along the Ondo State Shoreline

Coastal erosion represents one of the most pressing environmental challenges facing Nigeria's Atlantic coastline, with communities in Ondo State, South West Nigeria, increasingly vulnerable to shoreline retreat and flooding. This study assesses the rate and spatial extent of coastal erosion along the Ondo State shoreline, covering approximately 180 kilometres from Ilaje to Ese-Odo local government areas. Historical aerial photographs and recent Sentinel-2 satellite imagery from 2015 to 2024 are used to compute shoreline change rates using end-point rate and linear regression methods within the Digital Shoreline Analysis System. Field reconnaissance is conducted to document erosion morphology, identify critical erosion hotspots, and assess existing coastal protection structures including sea walls and riprap installations. Socioeconomic surveys are administered to coastal residents to capture livelihood impacts and community perceptions of erosion severity. Preliminary analysis suggests accelerating erosion rates of two to four metres per year in unprotected sections, with significant property loss and displacement of fishing settlements. The role of longshore sediment transport, storm surges, and human interference such as sand mining is examined. The study recommends integrated coastal zone management strategies, including beach nourishment, mangrove replanting, and revised building setback regulations. Findings are intended to inform the Ondo State Ministry of Environment and the National Emergency Management Agency. Keywords: coastal erosion, shoreline change, Ondo State, integrated coastal management, sediment transport