PPRN Vaucluse Floods (84) — Hazard Zone Synthesis

This sheet provides access to localised data on the hazards of approved RPP floods in the Vaucluse. Hazard is the manifestation of a natural phenomenon such as floods or forest fires. It is studied by the state services, assisted by service providers and expert partners in the field, according to criteria specific to each of the phenomena. The study of the hazard makes it possible to develop the hazard map, which is one of the graphic documents of a PPRN. This map delimits the areas impacted by the natural phenomenon, distinguished by the intensity of the hazard, i.e. the level of danger encountered. The hazard map of a PPRN usually represents 3 types of hazard zones (i.e. 3 hazard levels): strong, medium and weak vagaries. Depending on the phenomenon studied, the exposed territory and the technical analysis tools, other hazard areas could be defined (e.g. residual hazard for flood hazard, very strong hazard for forest fire). The assessment of the level of intensity is not based on the same criteria according to natural phenomena, and it is important to consult the presentation note of a PPRN for the classification grid used. For PPR Floods, the assessment of hazards results from the combination of the maximum water height reached by the PPR reference flood (usually centennial flood) and the current velocity at any point in the flood zone. Depending on the PPRI and the sectors studied, the assessment of hazards may also result from an analysis of stream beds (hydrogeomorphology) that are more or less mobilised during flooding. It is recalled that the map of hazards of a PPRN does not directly entail planning constraints, unlike the regulatory zoning of a PPRN. However, this map is a geographical representation of the natural risk studied which deserves to be used as an element of information for the actors of the territory and the population, and where appropriate as an element of knowledge to prepare crises and adopt the right reflexes during an event.