Rôle et intérêt de zones d'écrêtement des crues

Flood cutting down areas role and interest

Cemagref, Division Hydrologie-Hydraulique, Lyon

Abstract

There are many stakes linked with river management and especially with Loire river: water ressource, environment, flood risk are the three main types. Flood plain areas may play an important function to satisfy part of these stakes. Their hydraulic functioning allow flood lamination and favour indirectly water ressource both in quantity and quality. They may keep an economic interest by productive activities which tolerate flood constraint or, indirectly, by leasure activities. At least, they have an essential role for environment due to specifc water ecosystems linked to them. The limits in the efficiency of classical works and social demand evolutions lead to find new management rules sumarised in the "Dynamic slow-down" concept. New methods like Inondability allows their effective uses to take into account the diversified stakes and situations along a river. Applied to Loire river, this evolution should favour a more harmonious development of the valley and a reduction of flood damages in case of exceptional flow, that, if it occures today, would have dramatic consequences.