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International audienceLevees are large alignment works on which only imperfect information are usually available. In this particular context, a probability-based model is suggested for evaluating the levee performance, taking into account imperfect data in a probabilistic format. Such a model will implement subjective probabilities that have been elicited by expert assessment to evaluate all criteria and uncertainties thereof. Based on a deterministic model of multicriteria aggregation and using Monte Carlo simulations, this will ultimately help build probability distributions for the performance indicator and for each levee section. The benefit of this model is to determine how much an evaluation may be trusted and to help decide which technical actions should be taken to improve a levee section performance. Résumé: Les digues sont des ouvrages à grands linéaires pour lesquels on ne dispose généralement que dinformations imparfaites. Dans ce contexte, on propose un modèle probabiliste dévaluation de la performance des digues permettant la prise en compte des données imparfaites sous format probabiliste. Ce modèle met en œuvre des probabilités subjectives élicitées par jugement expert pour lévaluation des critères et de leurs incertitudes. Sur la base dun modèle déterministe dagrégation multicritère et au moyen de simulations de Monte Carlo, il permet au final de construire des distributions de probabilité pour lindicateur de performance et pour chaque tronçon de digue. Ce modèle présente les avantages dapprécier la confiance qui peut être accordée à une évaluation et de guider le choix des actions techniques pour améliorer la performance dun tronçon de digue. © 2013 Copyright Taylor and Francis Group, LLC

Abstract. On August 29th of 2005, Hurricane Katrina hit the gulf coast of the United States leading to one of the most powerful disasters in history. Damage costs reached more than 100 billion dollars, as well as 150,000 flooded houses and 1,330 deaths. 10 years later, the damage remains visible in the city of New Orleans, and the rate of recovery is highly varied throughout different neighborhoods in the city. A popular idea is to associate this to the neighborhood social class, i.e. the poorer an area is, the more difficult the recovery process is. However the reality is more complex. This study looks at two economically similar and highly damaged neighborhoods, with two deeply different recoveries. The Lower 9th Ward, an isolated, and poor neighborhood surrounded by water with the Mississippi River and the industrial canal, has experienced an extremely slow recovery. However, in the isolated and relatively poor neighborhood known as Village de l'Est, located on former marshes at the edge of the city between Lake Pontchartrain and the Bayou Bienvenue, the Vietnamese community ties and cohesion have brought the neighborhood back to fruition faster than anyone would have expected. Despite many common features weakening their technical resilience, such as relatively modern and fast urbanization on former natural and low lands protected mostly by levees, their radically different reaction following Katrina points out the key role of social resilience. This communication will aim to present decisive social aspects of resilience aside from geophysical and physical features such as risk awareness, social link and community culture.

International audienceLevees are large alignment civil engineering works with a performance that is assessed with great difficulty due to its longitudinal variability. We hereby suggest that a decision-making support procedure should be identified, built and implemented so as to split levee alignments into homogeneous sections and identify them according to their performance level. Our work is focused on defining actions for the purpose of solving the decision-making problem with regard to large alignment works. In order to select a suitable decision-making method, we suggest a formulation and a comparison between two types of multi-criteria methods: the ELECTRE TRI outranking method and a unicriterion method. The relevance of building a unicriterion for the purpose of our study is investigated considering the existing operational interconnections between the levee evaluation criteria