Abstract
The estimation of debris-flow volume is a fundamental task for the design of any hazard mitigation intervention in a mountain channel. The estimation 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 (stage sensors, geophones, etc.). Finally, volume estimation may be performed after the occurrence of the phenomenon, surveying the deposits left 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 method 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 SedAlp, has been recently funded by the Alpine Space programme. An important focus of the project is on methods and data collection on sediment transport. In this context, one of the activities that is taking place in a pilot area consists in the comparison of the different methods and procedures for debris-flow volume estimation.