摘要：Despite the strong societal impact of natural hazards,their documentation remains incomplete, with only a few inventoriesexceeding the past two centuries. Surprisingly enough, this also applies toEurope, a densely populated territory, and to floods, which along withstorms are the most common and damage-causing natural hazard in Europe. Inaddition, existing inventories have often been compiled by scientists andtechnicians and are used for risk management in a top-down manner, althoughthe participation of all parties concerned has been recognized as a keyfactor for disaster reduction. To address this double paradox, the presentarticle presents the regional flood risk observatory ORRION for the Alsatianregion, north-eastern France, and its very rich data content. Stemming fromtwo successive interdisciplinary and transnational French–German researchprojects, ORRION was designed as a participative online platform on whichinformation is shared between individuals, stakeholders, engineers, andscientists. This original approach aims at maximizing knowledgecapitalization and contributes to building a common knowledge base for floodrisk. ORRION is organized by events including all river floods that havelikely arisen from a single synoptic situation. For each event, it documentsinformation sources, date of occurrence, causes, and consequences in termsof damage and affected river basins and municipalities. ORRION has contributedtoward renewing our knowledge of flood hazard and risk in the target area.Notably, here, long chronicles of floods are derived for 13 rivers, theRhine and most of its main Alsatian tributaries and for all Alsatianmunicipalities, most of them since the end of the 15th century butover more than one millennium for the Rhine. Their main characteristicsaccording to various typologies (seasonality, causes, severity, etc.) areanalysed. Major developments over the study period related to sources, landuse, and/or climate change are identified. The advantages and limitations ofthe approach are discussed, and the potential to expand both dataexploitation and build common flood risk knowledge is outlined.
