The Manival near Grenoble (French Prealps) is a very active debris-flow torrent equipped with a large sediment trap (25 000 m3) protecting an urbanized alluvial fan from debris-flow. We began monitoring the semdiment budget of the catchment controlled bu the trap in Spring 2009. Terrestrial laser scanner is used for monitoring topographic changes in a small gully, the main channel, and the sediment trap. In the bedload transport after the events in 2009 and 2010 are presented revealing the dependency of the sediment supply from the production zone of the torrent catchment. The past two years the torrent storage has been identified as to have a decreasing trend despite seasonal recharge.