Influence de la structure de l'îlot urbain sur le schéma d'écoulement le long d'une rue inondée

International audience; The study of flooding in urban environments has some complexity, mainly due to the presence of buildings, among others (e.g., vehicles, street furniture, drainage system, underground transportation system). These buildings and their facilities are grouped into blocks that are normally assumed to be impervious in urban flood studies. However, water enters these blocks through different openings such as e.g., windows, doors, gates, fences, and these lateral flow exchanges between streets and blocks can locally alter the flow pattern. In order to study these exchange processes and their influence on both flow depth and velocity in the streets during flood events, experiments were conducted on a devoted physical model termed MURI (Urban Model for the study of Inundation Risk), at Irstea, Lyon-Villeurbanne, France. The present study focused on two geometric configurations, a straight street flanked by two lateral cavities, and a straight street flanked by one-side opening. These flows were also compared to a quasi-uniform flow (reference flow without openings). The experiments have shown that a detailed description of the building blocks is required if flow depths and velocities (flood hazard) has to be locally estimated.