Hold of underground cavities in Vienna

Since 2010, the State, in the Department of Vienna, has initiated a series of inventories to assess “cavitated” risk in its territory. In 2010, cavity inventories were carried out by the Bureau de Recherches Géologique et Minières (BRGM). They are based on a national methodology that allows data to be collected from the consultation of available bibliographical references as well as the questioning of all the municipalities of the department.The information concerning all the listed cavities can be found on the site: www.georisques.gouv.fr On the basis of this inventory established in 2010, more detailed inventories were carried out on a selection of municipalities. These studies, conducted by the BRGM, consist of identifying and summarising the cavities present in each communal territory and assessing the issues impacted on the surface. A (non-exhaustive) topographic survey of the cavities was conducted to visualise the ground rights of each underground cavity and thus characterise the surface issues impacted by the presence of these voids. In general, the stakes are people, property, activities... threatened by a hazard (here, the collapse of the soil due to the presence of underground cavities), and who are likely to be affected or damaged by them. The areas impacted by the cavities will need special attention from the local authorities in order to best control urbanisation in under-cavated areas. In addition, in other studies (development of PPRs, geotechnical studies related to development projects) the underground cavity right-of-way was lifted and mapped. This table includes the right-of-way of the underground cavities identified during the various detailed inventories and studies carried out in the department of Vienna.