Resumen de Cartography of Flood Risks Due to Extreme Storm Surges on the Central Algerian Coast (Eastern Coast of Cherchell)

Nadia Amarni, Lounes Fernane, Mohammed Naili, Ryhane Lounas, Rabah Belkessa

• Located in the south of the western Mediterranean, in the central Algerian region, the eastern coast of Cherchell is characterized by its ecological, agricultural, tourist, cultural and patrimonial vocations and by its low topography in many places. It has participated over time in the economic development of the region (agriculture and beach tourism). In recent years, this coast, like all the world's coastlines, has been subject to several coastal hazards such as marine flooding. Flooding is the most frequent and most important threat in terms of induced impacts, and therefore any management plan needs to assess it, noting that no such study has been carried out in the region despite its economic importance. The objective of this paper is to assess the land area flooded by extreme sea levels. Therefore, by combining a high-resolution numerical terrain model with geographic information systems (GIS), the areas at risk of flooding were mapped. The results indicate that most of the flooded land is at the annual return period of extreme sea levels, which is explained by the low topography of the beaches (Hamdania and Bella) and the wadi plains (El Hachem and El Bellaa) near the coast, whereas the extreme marine levels of hundred-year return period do not really exacerbate the flooding risks, due to the mountainous topography of the region which becomes progressively higher when moving away from the coast and the wadi plains. These results represent a basic tool for local managers and decision-makers to adapt planning practices and policies for a better management of these vulnerable areas, and a good adaptation in case of risk.