Plaquette : Making the Senegal river navigable - IAGF 6ème session

The entire shoreline is receding by an average of 6 m a year. One way of slowing this erosion - without stopping it completely – is replanting, a practice that many villages implement spontaneously. Another method concerns the nourishment of beaches (recharging with sand), to withstand strong storms and w inds and avoid the construction of stone levees that cause the disappearance of beaches and the natural shoreline. Areaswith naturally salinized soils are very frequent in the coastal mud flats of tropical regions, but they expanded here during the drought period between 1968 and 1990. Now, the progression of salinization can no longer be attributed to drought alone. The salt content of the groundwater is very high in the Guandiol region, where the coast is exposed due to a breach opened in 2003 . ln other areas, the problem of over-salty drinking water is a concern for villages that have int roduced motorised pumps or which have built too many tourist facilities. Most of the villages currently have access to drinking water free of salt though increasing problems could worsen this situation in the future. Indeed, Senegal is affected by a rare phenomenon, that of inverted estuaries: in the Saloum and Casamance regions, salinity increases the further one goes upstream. These shallow estuaries form large surface areas in wh ich the seawater evaporates, wh ich explains why the salinity gradient increases from the coast to inland areas . The height of the sea water increases the risk and frequency of submersions by waves and storms. Coastal cyclones have been observed regularly since 2014 and are a new phenomenon that can be explained by global warming . They can have considerable impacts: the opening of breaches on the coast, the loss of harvests in rice-growing areas ... despite the fact that th is age-old farming trad ition requires salinity and submersions! 9