This paper investigates the possible formation ofa landslide dam on the Kanyosha River near Bujumbura,the capital of Burundi, as well as the interplay between thebreaching of this landslide dam and the flooding along theriver. We present an end-to-end analysis, ranging from theorigin of the landslide up to the computation of flood wavesinduced by the dam breaching. The study includes three mainsteps. First, the mass movement site was investigated withvarious geophysical methods that allowed us to build a general 3-D model and detailed 2-D sections of the landslide.Second, this model was used for dynamic landslide processmodelling with the Universal Distinct Element Code. The results showed that a 15 m high landslide dam may form on theriver. Finally, a 2-D hydraulic model was set up to find out theconsequences of the breaching of the landslide dam on flooding along the river, especially in an urban area located downstream. Based on 2-D maps of maximum water depth, flowvelocity and wave propagation time, the results highlight thatneglecting the influence of such landslide dams leads to substantial underestimation of flood intensity in the downstreamarea.
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