Comparison of methods and procedures for debris-flow volume estimation

Arattano M.1, Bertoldi G.4, Cavalli M.2, Comiti F.3, D'Agostino V.4, Theule, J.3, 2014, Comparison of methods and procedures for debris-flow volume estimation, xii iaeg iNTERNATIONAL cONGRESS, TORINO, Settembre 2014,

The estimation of debris-flow magnitude (i.e. volume) is a fundamental task for the design of any hazard mitigation intervention in a mountain channel. The esti-mation may be carried out before the occurrence of a debris flow through methodologies aimed at assessing the debris potential in the basin. It can be carried out through instrumentation deployed along the torrent (radar sensors, ultrasonic sensors, geophones, etc.). Finally, volume estimation may be performed after the occurrence of the phenomenon, surveying the deposits left by the debris flow in the channel, in a possible retention basin or on the fan. The surveys can be carried out through a conventional topographic survey, through a terrestrial laser scanner (TLS), by photogrammetric techniques, etc.. Each of them delivers approximated results, due to different reasons. A systematic comparison of the results of these different estimation procedures, carried out simultaneously in the same catchment, might help to better understand their advantages and limitations, to improve their output and to validate and standardize the respective methodologies. An European Territorial Cooperation project, named "Sediment management in Alpine basins_ integrating sediment continuum, risk mitigation and hydropower" (SedAlp), has been recently funded by the Alpine Space programme. An important focus of Sedalp project is on methods and data collection on sediment transport. In this context, one of the activities that is taking place in the pilot area of the Gadria basin (Eastern Italian Alps), consists in the comparison of the different methods and procedures for debris-flow volume esti-mation.

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