摘要：Sediment detention basins, also called SABO dams, are key
facilities in flood protection systems of mountain catchments, specifically
in torrents prone to massive bedload transport or debris flows. A better
understanding of the processes generating sediment trapping is required to
optimize their functioning. Two monitoring stations have been
implemented in the French Alps on two torrents: the Manival (SaintNazaire-Les-Eymes)
and the Claret (Saint-Julien-Mont-Denis). Time-lapse
photos show an event depositing 10,000 m3
of debris flow in a basin in less
than six minutes and several events partially filling the other basin with
gravel, impairing its capacity to store debris flows later. After a
presentation of the catchments, this paper qualitatively analyzes the
dynamics of the depositions. It highlights and stresses the consistency and
differences between bedload and debris-flow deposition. Overall, despite
clear differences of geomorphic activity, deposits tend to fill the trap basins
just enough to enable the sediment transport continuity reestablishment
through the basin. The open check dams thus play a role only provided that
this continuity precondition is completed. These observations enhance our
comprehension of massive sediment trapping in torrents and our capacity
to better adjust trap maintenance and design to the objective sought in each
site.
其他摘要：Sediment detention basins, also called SABO dams, are key facilities in flood protection systems of mountain catchments, specifically in torrents prone to massive bedload transport or debris flows. A better understanding of the processes generating sediment trapping is required to optimize their functioning. Two monitoring stations have been implemented in the French Alps on two torrents: the Manival (Saint-Nazaire-Les-Eymes) and the Claret (Saint-Julien-Mont-Denis). Time-lapse photos show an event depositing 10,000 m3 of debris flow in a basin in less than six minutes and several events partially filling the other basin with gravel, impairing its capacity to store debris flows later. After a presentation of the catchments, this paper qualitatively analyzes the dynamics of the depositions. It highlights and stresses the consistency and differences between bedload and debris-flow deposition. Overall, despite clear differences of geomorphic activity, deposits tend to fill the trap basins just enough to enable the sediment transport continuity reestablishment through the basin. The open check dams thus play a role only provided that this continuity precondition is completed. These observations enhance our comprehension of massive sediment trapping in torrents and our capacity to better adjust trap maintenance and design to the objective sought in each site.
