Sediment and large wood trapping structures, also called SABO dams or open check dams, are regularly used in debris-flows and debris-flood mitigation schemes. They are very effective and efficient when used at appropriate sites and then correctly designed & maintained. Still, the processes occurring in these structures that result in the trapping of all or part of the solid load remain poorly understood. As a consequence, numerous structures are ill-designed generating high maintenance costs, the requirement for complementary works, and/or a higher likelihood of failure. Better understanding the driving mechanisms of deposition and erosion processes at the fan scale and at the structure scale may help design engineers to select the best type of structure for a given site and to design its shape and geometry in the most efficient manner.

This webinar will clarify the typical cascading processes resulting in deposition and flooding that are involved in interactions between fan channel and sediment & large wood-laden events. Those cascading processes make particular necessary changes in the debris-flows or debris-flood processes eventually using trapping structures or other structural measures. Participants will learn what can and cannot be achieved with open check dams, draw a simple portrait of the five main types of structures in relation with their particular function, and review the main existing design criteria helping to define the geometry of the dam and its basin.

This webinar is strictly dedicated to review and train engineers to decide whether or not trapping structures seem relevant for a given site and to perform the functional design of the basin and the open architecture, i.e., to define type, shape, and geometry. The webinar will not cover the structural design (impact forces, load scenario, internal and external stability) and will slightly cover the maintenance policy.