Costs of landslides and floods in XX Century in a Calabrian town starting from the data stored in the Historical Archive of IRPI (Cosenza)

The paper firstly presents the historical archive of Cosenza IRPI Section and the historical database that has been built basing on the data contained in it. Then, an application of these data to Catanzaro, the town that is the administrative center of Calabria region (Southern Italy), is presented. The gathering of historical data on past floods and landslides in Cosenza IRPI Section has been started since 1996, and it is still in progress. In 2005, some donations coming from regional and municipal PublicWorks offices greatly increased the documental corpus, and required a more incisive classification and management that led us to organize the documents in a real historical archive. Documents were sorted according to municipalities they concerned. In this way, for each of the 409 municipalities of Calabria a set of documents, maps and images was available. Collected documents mainly concern damage caused by the occurrence, since XIX century, of phenomena as floods, flash floods and landslides triggered by extreme meteorological events, or even damage caused by strong earthquakes. At the beginning of 2014, the central office of IRPI (Perugia) funded a project aiming to the digitalization of the archive and the subsequent publication of it on a web-platform. In this paper, the procedure adopted to build the archive and implement the database is described. Then, the elaboration of the historical series of data on Catanzaro town, which has been frequently damaged by rainfall-induced landslides and floods, is also presented. Basing on the documents coming from the archive of Ministry Public Works and stored in our Historical Archive, an assessment of costs related to damage that during XX century affected the houses of this town has been performed. The research pointed out the types of most damaging phenomena, the municipal sectors most frequently damaged, and the evolution of damaged areas throughout the years according to the increasing urbanization.