Floodplain Backwater Effect on Overtopping Induced Fluvial Dike Failure

Abstract

Fluvial dikes (i.e., levees) can be damaged by overtopping flows, leading to breach formation and severe floods. Accurate prediction of the breach geometry and outflow hydrograph is crucial to achieve sound inundation risk assessment and mitigating measures. A set of laboratory experiments were performed to study overtopping induced fluvial dike breaching. The effects of floodplain tailwater on the breach expansion and outflow were investigated. Results are compared to previous experiments under different main channel inflow discharges combined with a free floodplain. The dike breaching process follows three stages: gradual start of overtopping and slow initiation of dike erosion, fast deepening and widening of the breach with highly transient flows, and flow quasi‐stabilization with or without sustained breach expansion. Using the recorded data, a simplified regression model relating the breach stabilization time and the final breach width to the floodplain confinement and inflow Froude number in the main channel is proposed.

Continuous Monitoring of Fluvial Dike Breaching by a Laser Profilometry Technique

“…In both models, one complete dike sweeping lasted Selected experiments are presented in this paper, but the focus is on the demonstration of the capabilities of the LPT, rather than on the findings of the fluvial dike breaching experiments. Readers may refer to the works carried out by Rifai et al (2017Rifai et al ( , 2018) for more details.…”

“…Dike breaching is a challenging concern both from the perspective of the scientific issues that are involved (e.g., physical processes, monitoring, and numerical modeling) and for the practical consequences of the induced floods (e.g., casualties and damage). The knowledge of processes involved in breach expansion still calls for further research efforts (Frank, 2016;Rifai et al, 2017Rifai et al, , 2018, and despite some advances (e.g., Amaral et al, 2020;Dazzi et al, 2019;Dewals et al, 2018;Kakinuma & Shimizu, 2014;Onda et al, 2019), the current status of breaching numerical modeling remains unsatisfactory. The breach development is poorly represented, and large uncertainties prevail in the numerical results (Elalfy et al, 2017;Volz et al, 2017), contrasting with the needs of robust tools for the design of flood hazard maps, emergency plans, and mitigation measures.…”

Flow and detailed 3D morphodynamic data from laboratory experiments of fluvial dike breaching

“…Therefore, the breach growth dynamics and subsequent breach flow hydrograph have to be accurately estimated as they are key inputs for flood risk analysis and management. The present dataset is the outcome of a research project aiming at improving our understanding of the physical processes underpinning breach expansion and breach hydraulics in the case of fluvial dike failures 3,12 . A comprehensive test program was conducted (54 tests) on two experimental models, shedding light on dike breaching dynamics in various realistic configurations, including varying: (i) channel flow conditions, (ii) channel dimensions, (iii) floodplain confinement level, (iv) bottom erodibility, and (v) dike material composition.…”

“…3 which focuses on the channel flow condition effects on dike breaching and (ii) the work conducted by Rifai et al . 12 investigating tailwater effects, i . e .…”

Barrier lake formation due to landslide impacting a river: A numerical study using a double layer-averaged two-phase flow model

“…Over the past few decades, numerous efforts have been devoted to study barrier lake failure and the resulting flood, including laboratory experiments [10][11][12] and numerical modeling studies [13][14][15][16][17][18]. However, studies on barrier lake formation remain rare.…”