Effetti degli eventi alluvionali del settembre 1992 nelle aree di Genova e Savona

Abstract

On the 28th of September 1992, 435 mm of rain fell onto the Molassana Station in the Bisagno River basin with an ensuing flood causing severe damages to the eastern urban area of Genoa and numerous landslides on the surrounding hills. At the same time, the Sturla River, adjacent to the Bisagno River, overflowed causing two casualties, injuries and devastation in several urban areas. In the area of Savona, floods by the Sansobbia, Letimbro and Quiliano torrents were devastating (a rainfall peak of 390 mm was measured on 23rd September, 1992 at the Stella Station in the Letimbro River basin): casualties, missing and injured persons, devastation of shops, workshops, ground floors of residences, garages, wharehouses ensued, and many bridges collapsed. The surveys at our disposal before the rainfall event and the data collected soon after the floods, once again show the irresponsible attitude of Man with regard to rain and streams and his lack of knowledge on the use of territory. For a long time slopes have been abandoned, and constructions occupy river embankments up to exposed river beds, forcing the river to flow in a artificially restricted course. The expanded use of asphalt and concrete without the compensatory planting of trees has caused an increase in river power and speed. Lack of river bed maintenance has favoured the pernicious growth of thick vegetation and brushes, the accumulation of all kinds of waste products and of litter and industrial refuses. Furthermore river beds have continued to be used as free-of-charge multiporpuse building areas.