ESP AD A, A UNIQUE FLOOD MANAGEMENT TOOL: FIRST FEEDBACK FROM THE SEPTEMBER 2005 FLOOD IN NIMES

摘要

In France, the serious damages caused in urban areas by the recent floods (like Nimes in 1988 or Marseille in 2000) showed the importance of efficient and adapted reactions of the municipality. Faced to a flood crisis, decisions should be taken based on the current information available that are often very limited due to the lack of time to obtain, manage and analyse them. Therefore, ESPADA is an integrated tool that was developed to forecast and manage urban flooding in real time. The modelling system is based on predicted precipitations from radar imaging, a rainfall-runoff model, a hydraulic model developed for urban area and a risk definition representing the flood importance. For its first application, this innovative system has been developed for the city of Nimes and the first results were obtained for the floods that occurred in September 2005. Concerning the system performance, couple of important lessons can be learnt from such an event. The following points are analysed : (ⅰ) implementation of meteorological scenarii for stationary storm cells, (ⅱ) reinforcement of the in situ video control of the main overflow points and (ⅲ) data validation (detection of unrealistic values) and (ⅳ) consideration of the karst contribution. Finally, the good performance of the system is very promising and proves the significant advancement obtained when combining the growing computer power and the increasing urban hydrological knowledge.