Map Viewing Service (WMS) of the dataset: Plan for the prevention of natural flood risks — Communes of the Tarn sector — Zone d’aléas — Department of Tarn-et-Garonne

Area exposed to one or more hazards represented on the hazard map used for risk analysis of the RPP. The hazard map is the result of the study of hazards, the objective of which is to assess the intensity of each hazard at any point in the study area. The evaluation method is specific to each type of hazard. It leads to the delimitation of a set of areas on the study perimeter constituting a zoning graduated according to the level of the hazard. Award from a hazard level to a given point in the territory takes into account the probability of occurrence of the dangerous phenomenon and its degree of intensity. For multi-random PPRNs, each zone is usually identified on the hazard map by a code for each hazard to which it is exposed. All hazard areas shown on the hazard map are included. Areas protected by protective structures must be represented (possibly specific) because they are always considered to be subject to hazard (case of breakage or inadequacy of the work). Hazard zones may be described as data compiled to the extent that they result from a synthesis using multiple calculated hazard data sources, modelled or observed. These source data are not concerned by this class of objects but by another standard dealing with the knowledge of hazards. Some areas within the study area are considered “no or insignificant hazard zones”. These are the areas where the hazard has been studied and is nil. These areas are not included in the object class and do not have to be represented as hazard zones. However, in the case of natural RPPs, regulatory zoning may classify certain areas not exposed to hazard in a prescribing zone (see definition of Class PPR).