The Landslide Dam of Ventia Creek (Umbria, Central Italy)

Abstract

A landslide dam is a natural phenomenon in which the movement of a large quantity of material down the slopes dams a river. This paper presents a case of a dammed river where the natural lake has remained stable. The type and volume of the material are the main elements controlling such phenomena. A higher quality, digital elevation model was obtained with the use of a geostatistic approach, which couples an auxiliary map with the elevation data. A comparison between the DEM from before the event and after the event enabled the volume involved to be estimated more precisely and the main landslide features, such as the crown, the depletion zone and the accumulation zone, to be identified. The study enabled a method to be developed, which uses geostatistic interpolation techniques and auxiliary maps to achieve a better definition of the digital terrain model and, therefore, a more accurate assessment of mobilised volumes during the event, when topographic data are lacking.