First tests of Cartino2D method on Toulon French metropolis

To establish a flood risk assessment on its small coastal catchments for a PAPI project (flood prevention program), Toulon French metropolis and Cerema have been working together to test Exzeco and Cartino1D mapping methods and compare them with local knowledge on flood occurrences. The mapping work is based on flood scenarios with a high probability to low probability. Cartino1D results were not adapted to well represent all the scenarios particularly with a high probability in this topographic and urban specific context. This led to propose a 2D hydraulic modeling approach, based on Telemac 2D software. Telemac2D with the rainfall-runoff module was used on three sectors covering about 180 km(2). A new Cartino2D method enables us to use Telemac software on the whole territory. 66 sectors were created covering also about 180 km(2). Cartino2D can create the mesh for Telemac automatically and integrate many rain scenarios. At the end, post processing provides automated maps under GIS form of the 69 sectors and 8 rainfalls. Results of the various methods were compared with local studies. Historical data (interventions of firefighters, photos, videos, flood marks) has been compared with 2D results. The proposed 2D automated approach appears attractive in terms of mapping results and consistent with local studies and historical data. However, technical validation is limited by insufficient data in terms of quality and quantity. An effort must be made to capitalize on knowledge and make the models or the use of the models more reliable. At the end, a hazard and vulnerability mapping has been established to provide a homogeneous diagnosis of the territory.