Case study: effects of urban sustainable development on floods in the Grand Paris

Grand Paris is a new global plan for the Paris metropolitan region; it has lead to a new transportation master plan and to development of several areas around Paris. Our case study is the project of national interest (Opération d’Intérêt National) by EPA ORSA (public institution of town planning Orly-Rungis-Upstream Seine river), located in the south-east of Paris suburbs, including Seine and Marne rivers. The urban sustainable development of this area should be finished in 2050, its aim is to “live with the river ” but at the same time increase the resilience. We have created a 2D model (with TELEMAC 2D) of the EPA ORSA territory, and run several urbanization scenarios for different stages of the project (2011, 2018, 2025 and 2050) and ten flood events. The redevelopment of the Seine Valley has to respect the French Water Act and then cause zero impact. Also, we have built a 1D model (with HEC-RAS) to spread the water level and discharge impact in the Seine Valley (upstream and downstream of the 2D area). Through the “Grandes Ardoines”, located in Vitry example, we can see that a