ABSTRACT
Fluvial dyke breaching is a major concern for flood risk management; but the mechanisms of dyke breaching remain incompletely understood. We report here on forty (40) laboratory tests performed to assess the influence of the geometry of dykes made of non-cohesive sediments on the evolution of the breach discharge. Three parameters were systematically varied: the side slopes of the dyke and its crest width. Each geometric configuration was tested for several main channel inflow discharges. Results show that the breach discharge grows faster when the dyke volume becomes smaller and when the inflow discharge is increased. All geometrical parameters were then lumped into a single non-dimensional parameter and a characteristic time was defined to quantify the growth rate of the breach discharge. For a given inflow discharge, the proposed characteristic time increases linearly with the non-dimensional parameter.
