Sediment dynamics in mountain drainage basins

Mountain drainage basins are intrinsically transitional systems, in that they connect water, sediment, and wood fluxes from hillslopes, chiefly dominated by mass-wasting processes, to high order streams, in which fluvial transport prevails. Owing to the variety of hillslope-channel interactions, the transient forcing of tectonic activity and the imprinting of Pleistocene glaciations, in conjunction with ongoing atmospheric temperature rise and increasing anthropogenic impacts, mountain drainage basins can exhibit complex, largely unknown sediment dynamics. An improved understanding of these systems is needed for addressing fundamental scientific issues such as hillslope-channel coupling mechanisms and landscape evolution, as much as for solving more practical problems, including sediment management and the prevention/mitigation of coastal erosion, flood- and debris flow induced disasters.

Our work is focused on formerly glaciated mountain drainage basins of coastal British Columbia and the Alps (Trentino-Alto Adige region), and in unglaciated basins of the Apennines (Emilia Romagna region). Time scales of sediment flux investigation span from real time monitoring to millennial averages. In particular, we are currently working on: (i) bedload transport monitoring in Rio Grigno (Valsugana) and Rio Valle Ussaia (Val di Sole), as well as in the Santerno and Sillaro Rivers (Emilia Romagna); (ii) colluvial sediment dynamics via multi-temporal compilation of landslide and debris flow inventories in Val di Sole (Trentino), Val Venosta and Val Marebbe/Braies (Alto Adige); (iii) reconstructing the postglacial evolution of large debris-flow fans and hosting valley fills in Val Venosta by means of well drilling, radiocarbon dating and high-resolution seismics; (iv) constraining postglacial denudation rates by means of cosmogenic nuclides (Rio Gadria in Val Venosta and Capilano River in British Columbia; v) downstream hydraulic geometry of mountain streams (British Columbia and Val di Sole); vi) landslide response to forest management in the Tsitika and Eve watersheds (coastal British Columbia). We conduct these activities in collaboration with Metro Vancouver, Costabrunella srl, the Autonomous Province of Bolzano (Ufficio Geologia e Prove Materiali, Ufficio Bacini Montani), as well as with Regione Emilia Romagna (Ufficio Geologia e Servizio Area Reno e Po di Volano).