The effects of dredged channel geometry on the barrier lake outburst

The events of barrier lake outburst have been frequently reported under the impacts of earthquakes, climate change and human activities, which usually brought tremendous disaster to the downstream regions. Dredging a channel is one of the main measures to deal with the barrier lake risk. However, the effects of the channel geometry on the outburst have been unclear. Therefore, we conducted a series of large-scale field experiments on the barrier lake outburst responding to different geometry profiles of dredged channels. Results show that the barrier lake outburst with dredged channel has four development stages, i.e., erosion alongside the dredged channel, backward headcut erosion, rapid development and weak development. For all cases in this work, the peak stage in the reservoir appears earlier than the peak discharge. The rates of the enlargement of the dredged channel are similar among all the cases, while the start time of the enlargement and the final width of the breach are different. Digging of a small notch advances the enlargement of the breach.