Cartographie des zones inondables et analyse du risque inondation dans la plaine bas Isser,wilaya de Boumerdes.

Abstract

Algeria has been experiencing disturbances in the climate regime for a few years, the precipitation becoming more sudden, more intense and with devastating effects. Mediterranean watersheds are the most affected by this phenomenon "flash floods", many floods have been recorded in these basins in the image of the basin of Algiers, the Issers basin and Annaba. The damage recorded is enormous hence management of these disasters remains a priority.The purpose of our study is to contribute to flood management in a watershed by analyzing and mapping the areas most vulnerable to flood risk. Our study area is the Isser plain in the lower part of the large catchment of Wadi Isser. This region is characterized by an alluvial plain that receives all the waters that precipitate in the high altitudes of the surrounding mountains. The distance between the plain and the summits being short, with the low vegetation cover and the impermeability of the soil make the time of water concentration reduced, thus favoring the accumulation downstream at the level of the flood plain of the Oued Isser which contains very exposed issues. This study consists of manipulating a large mass of data (climate, satellite, field observations ... etc) in the GIS and remote sensing environment to first extract a map of the flood zones, then in a second time a map of the flood risk by multi-criteria analysis of hazard and issue data. The obtained risk map is a basic tool for any project and planning policy to reduce the risk of flooding in the Lower Isser region. This map offers the possibility of targeting intervention zones during development and orienting new projects beyond the risk zone