Case histories of lake-forming landslides in the Dragone valley (Northern Apennines, Italy)

The Torrent Dragone valley (Province of Modena) is affected by a very high incidence of landslides, due essentially to the dominant presence of argillaceous and shaly soils. This characteristic has always favoured the formation of large-scale landslides along entire slopes, which in some cases have determined the obstruction of the riverbed. Although the persistence of barrier lakes is limited, the risk connected with a sudden evacuation of the basins, where large amounts of water can be stored, should not be underestimated. The data resulting from geomorphological surveys and aerial photo interpretation have led to the identification of the slope portions where slope movements are still active or frequently recurrent and the riverbed more susceptible to the formation of new barrier lakes. The study is completed by investigations on the mineralogical composition of the clayey soils and their geomechanical properties, in order to better understand and assess the kinetic trends of the landslides.