Rapid debris volume estimation by LiDAR data derived DEMs: applications to the 25 October 2011 debris flood event at Vernazza (Cinque Terre, Italy)

This study describes an example of analysis of morphological changes by using high resolution DEMs derived from LiDAR data. The evaluation of eroded or deposition volumes is based on the comparison between topographical profiles derived from two time-series of high resolution DEMs. The proposed method has been applied to selected areas of the Vernazza basin (Cinque Terre, eastern Liguria) that suffered strong morphological changes due to the 25 October 2011 very intense rainfall event. Three human embankments areas located along channels, completely or partially destroyed during the event, were selected for calculating eroded volumes whereas five areas in the valley floor were investigated for estimating deposition volumes. The obtained results have shown the impact of human embankments in increasing the effects of very hazardous phenomena typical of hilly or mountain areas, such as debris flows and debris floods. The proposed method, although approximate, can be very useful when a rapid estimation of volume mobilized in specific areas is required.