Remote Sensing for Monitoring Shoreline Dynamics in the Cross River Estuary

The Cross River Estuary in Cross River State serves as a critical ecological corridor and economic resource for coastal communities dependent on fisheries, aquaculture, and mangrove products. Monitoring shoreline dynamics in this estuary is essential for sustainable coastal resource management. This study uses multi-temporal Sentinel-2 and Landsat imagery to track shoreline position changes along the Cross River Estuary from 2017 to 2023. Waterline extraction using the Normalised Difference Water Index produces shoreline vector data for six epochs. The Digital Shoreline Analysis System computes erosion and accretion rates along 150 shore-normal transects. Results reveal that the eastern estuarine bank experiences net erosion averaging 3.1 metres per year, driven by a combination of tidal action, reduced upstream sediment supply, and mangrove loss. Accretion dominates the western bank adjacent to active mangrove forests. The study recommends integrating shoreline monitoring data into the Cross River State Coastal Management Framework and supports mangrove restoration as a nature-based shoreline stabilisation strategy. Keywords: shoreline dynamics, estuary, remote sensing, Cross River, coastal monitoring