Coastline dynamics analysis in Dakar region, Senegal from 1990 to 2040

This study examines coastal shoreline dynamics in the Dakar region of Senegal, a subject of growing importance as climate change drives economic losses in coastal countries and makes shoreline behaviour a key parameter for understanding climate impacts in littoral zones. The study aims to characterize coastal dynamics separately for the period from 1990 to 2020 across the three distinct coasts of Dakar — which differ in their geologic, geomorphologic, and hydrodynamic conditions — and to project shoreline change forward to 2040, building on and comparing against previous studies. To do so, it applies a Geographic Information System (GIS) approach, one of the most widely used methods for determining coastline dynamics, drawing on historical Landsat imagery from the USGS and processing the data through QGIS 3.12.0, ArcGIS 10.4, and DSAS software to compute shoreline change rates and estimate future coastline positions using the derived velocity formula.

The results reveal contrasting dynamics across the three coasts. The northern coast is characterized by an average retreat rate of about -0.44 m/year, while the western coast shows accretion at roughly 0.21 m/year and the southern coast records a modest retreat of about -0.11 m/year. Projecting these trends forward, the study estimates average rates of -4.4, 2.1, and -1.1 m/year by 2030 on the northern, western, and southern coasts respectively, indicating a pronounced acceleration of erosion on the northern coast in particular. These findings underscore the value of GIS- and remote-sensing-based approaches for monitoring coastal change and supporting climate adaptation planning in vulnerable coastal regions.