Important Flooding (TRI) territories of the Clain and Vienna valleys in the agglomerations of Châtellerault and Poitiers

Based on the National Preliminary Flood Risk Assessment (EPRI) and the EPRIs of each River Basin District and their Addendums, 124 Significant Flood Risk (TRI) territories have been established throughout the national territory. These areas with significant flood risk are subject to an in-depth risk diagnosis. A risk mapping is thus carried out on each IRR and adopted by the Basin Coordinating Prefect (Decree of 22/10/2018). This mapping is a major step in the knowledge of the specificities of the territory, the uncertainties to which it may be subjected and in the localisation of the issues related to these events. The aim is to gain a better understanding of the vulnerability of the territory in order to know which management tools should be preferred. This mapping gives first access to the analysis of the vulnerability and socio-economic functioning of the area: exposure of sensitive establishments (hospitals, schools, Seveso companies), strategic locations of road networks, sensitivity of energy, drinking water or sanitation networks... Once the territory with a significant flood risk is identified and analysed against flood risks, the next step is to put in place targeted risk management to anticipate and reduce the impact of crises. With a high urban population density, IRRs receive special attention from public authorities to reduce the cost of flood damage. Thus, together with the State, local authorities manage these risks, within a relevant geographical area, through a local strategy to meet the ambitions of the National Flood Risk Management Strategy (SNGRI) which is subsequently developed by an operational action programme, the PAPI (Flood Prevention Action Programme).