Coastal Risk assessment and management-related issues of two sand spits at the southern coast of Senegal

This poster describes the southern coast of Senegal (Petite Côte Sénégalaise), characterized by a succession of large sandy spits with contrasting morphological evolution and degree of anthropization. The sandy spits of Mbodiène and Joal located on either side of the tip of Joal reflect this situation, the first spit (Mbodiène) being relatively unaffected by massive human occupation and the second (Joal) further south, considered one of the largest fishing ports in Senegal, being almost entirely urbanized. This paper deals with the evaluation of erosion and coastal risks, as well as the discussion of erosion management issues on the two sand spits. For this work, we calculated a Coastal Sensitivity Index (CSI) at a spatial scale of 1 km for the sand spits of Mbodiène and Joal taking into consideration coastal characteristics (geomorphology, coastline changes, coastal elevation, beach slope, bathymetry), coastal forcings (sea level rise, mean tidal range, significant wave height), and socio-economic characteristics (coastal population density, land use) as indicators. The study revealed that the high density urbanized sand spit in the south (Joal) is characterized by the highest risk, followed by some central areas with a significant erosive focus. In contrast, the more morphologically dynamic northern spit (Mbodiène), with developed beaches and dune systems, has the lowest level of risk.  These results could be useful in the development of adaptation strategies to increase the resilience of this coastal zone and then be extended to the management of the entire Senegalese coast characterized by numerous sandy spits.