Effect of Coastal Protection Works on Shoreline Variability in Rufisque, Senegal

Ndour, A.; Ngom, H.; Diadhiou, Y.B., and Ba, K., 2024. Effect of coastal protection works on shoreline variability in Rufisque, Senegal. In: Phillips, M.R.; Al-Naemi, S., and Duarte, C.M. (eds.), Coastlines under Global Change: Proceedings from the International Coastal Symposium (ICS) 2024 (Doha, Qatar). Journal of Coastal Research, Special Issue No. 113, pp. 326-329. Charlotte (North Carolina), ISSN 0749-0208. Coastal erosion, which is a threat to the Rufisque coastline, induced the building of protection works in the 1980s, leading to environmental degradation of the beaches and their disappearance. A comparison between the shoreline positions in 1954 and 2006 show that the entire coastline, with the exception of the beach between Cap des Biches and the thermal power station, is eroding with an annual rate of between 0.4 and 1.5 m/year, which is in equilibrium, or even slightly prograding (+ 0.15 m/year). However, the shoreline evolution experienced very significant spatial and temporal variations, especially after the hardening of almost all of the beaches by the seawalls. Studying the long-term evolution of the shoreline (more than 50 years) helped us estimate the impact of these protection works. Beyond the recognized mitigation of the coastline retreat they induced just after being built and the protection they offer residents against the strong rainy season swells, the seawalls have intensified the rate of retreat of the shoreline, especially at the southern end due to the fact that the swells are behind them.