Flood risk management and the "Inondabilité" method: a socio-economic perspective

Abstract

To deal with flood risk management, it is now accepted to consider the risk as the comparison between vulnerability and hazard. The "Inondabilité" method uses this concept in order to provide tools for river management. In order to compare the two notions of vulnerability and hazard, we use a discharge-duration-frequency (QdF) hydrological model. It allows the transformation of the two previous components in the same unit and we can finally have a risk map. These results help for an objective negotiation for an adapted river management taking into account many stakes: flood risk but also water resource and environment. We try to show the particularity of the "Inondabilité" method, compared to some classical methods used for risk management, especially in the field of economic valuation. The concept of average annual damage cost, as the main estimator of vulnerability, seems not to be very well adapted to the nowadays situation of land use and river management. We prefer an analysis of the maximum acceptable risk that allows a positive management of land use. This approach gives appropriate answers for river management, adapted to local land use and improves the global economic optimum.