Map Viewing Service (WMS) of the dataset: PPRi hazard zone of the Issoirian alloy val(63DDT20110004) approved on 19-12-2013 — Puy-de-Dôme

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 hazard type. 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. The allocation of a hazard level at a given point in the territory takes into account the probability of occurrence of the dangerous phenomenon and its degree of intensity. In this PPR, three levels of hazard (low, medium and strong) are defined according to water heights and flood flow velocities that can result in impacts s potentials more or less strong for people and goods: • strong hazard: water heights greater than 1 metre or flow speeds greater than 1 metre per second, •medium hazard: water heights between 50 cm and 1 metre, and flow velocities between 0,5 and 1 m per second, •low hazard: water heights less than 0.5 metres and speeds less than 0.5 metres per second.用于RPP风险分析的灾害图所标示的、遭受一种或多种灾害影响的区域。 灾害图为灾害专项研究的成果，其研究目标为评估研究区域内任意点位的各类灾害强度。该评估方法因灾害类型而异，最终会在研究范围内划定若干区域，形成按灾害等级分级的区划。 对区域内特定点位的灾害等级进行划定时，需综合考量该危险现象的发生概率及其强度等级。 本PPR中，依据可能对人员及财产造成不同程度影响的水位高度与洪水流速，划定了三级灾害等级： • 强灾害：水位高度超过1米，或流速超过1米/秒； • 中灾害：水位高度介于0.5米至1米之间，且流速介于0.5米至1米/秒之间； • 低灾害：水位高度低于0.5米，且流速低于0.5米/秒。