Decision support tools for natural hazards management under uncertainty: new approaches based on multicriteria decision analysis and evidential reasoning

The natural risks management process involves several temporal steps (preparedness, mitigation, crisis management, recovery...) and spatial zones (triggering, propagation and deposition or extension areas). Decision support systems are expected to help the experts, the risk managers, the local authorities to take difficult decisions often based on imperfect information provided by more or less reliable sources. This paper presents two methodologies related to the development of decision support dedicated to risk management. First, the global methodology to analyze a multicriteria decision problem is presented in the context of the analysis of criticality of road sections exposed to natural hazards in the framework of the Paramount project. Secondly, we describe the ER-MCDA (Evidential Reasoning – Multicriteria decision analysis) that associates the principles of Analytic Hierarchy Process (AHP) and new uncertainty theories such as Fuzzy Sets, Possibility and Belief Functions theories. An extension of this method to spatial information is also presented.