Vulnerability of urban areas to flooding: events in the North-West Italy, november 1994

The flood occurred on November 5-6, 1994 in North West Italy has emphasized the susceptibility of many urban areas towards river dynamics processes. In Piedmont 130 towns were flooded and a huge amount of lives got lost (50 were those directly caused by the flooding). A detailed analysis about the flooding of the urban areas of Alessandria, Asti, Clavesana and Ceva was carried out to recognise the reasons of the extreme vulnerability shown by Piedmontese towns towards river dynamics. The study was integrated with the reconstruction of the transformations, both natural and anthropic, that the landscape underwent during the last two centuries. The results clearly show how the flood effects were amplified or directly influenced by the anthropic installations on the territory. The methodology presented may be regarded as a tool to define areas subject to flood hazard and to correctly plan their territorial developr or consolidation). In 1988-93 the CNR-IRPI, in cooperation with the Geological Sector of the Piedmont Region, carried out such a research for 41 Piedmontese urban sites (Luino et al., 1993), verifying their extreme vulnerability towards river and slope processes. The recent hydrometereologic event did not only confirm the well known hazardous conditions of these sites, but also manifested, in a much wider territorial sphere, the need for a methodology able both to deepen significantly the knowledge of the interactions between human establishments and geomorphologic processes, and to provide useful tools for a correct planning of the environmental set-up.