Semi-automatic Maps for 2015 French Riviera Floods

During 2015 French Riviera floods, precipitation with exceptional intensity was recorded. Floods occurred on small rivers but also on small dried thalwegs often forgotten or urbanized. Cerema was involved in the data construction of the flood event survey. More than 700 flood marks are now available in the national flood mark database on the website http://​www.​reperesdecrues.​developpement-durable.​gouv.​fr/​. The structure of this database (flood marks, photos, videos, damages) enables to compare knowledge available before and after 2015 floods, particularly with knowledge provided by the work made after the flood directive was implemented. To provide quickly flood hazard maps (for urban planning) covering all affected areas, Cartino model was used. Cartino is a semi-automatic 1D hydraulic model, based on three hydraulic software (Mascaret, Hec-Ras and Flutor). It covers 80 basins and more than 250 reaches. A feedback on strengths and weaknesses of this approach in this case will be explained. We also propose an evaluation grid to know when to choose this type of approach, mixing uncertainty on topography, discharge, roughness, reliability of software for steep slope.