Author(s): L. Schmocker; W. H. Hager
Linked Author(s): Willi H. Hager
Keywords: Dike breach; Erosion; Hydraulic modelling; Overtopping; Scale effects
Abstract: Dikes along rivers are designed to protect a valley including its population and property from floods. Many dikes have not been maintained or repaired during decades and overtopping has caused large damages. These flood events highlight the need to understand the damage processes due to overtopping. An accurate prediction of dike failure is essential to develop effective emergency action plans and to design early warning systems and hazard maps. In this project, systematic plane dike breach tests due to overtopping were conducted in a laboratory channel to examine the dike erosion processes and the model limitations. All dikes were of trapezoidal shape, consisting of uniform non-cohesive sediment and not protected by a core or a surface layer. The temporal dike breach progress was optically recorded to allow for a detailed analysis of both the water and the sediment surfaces. This research provides general results regarding the overflow erosion process, seepage effects and scaling issues. Minimum dimensions for both the dike height and width, the sediment diameter and the overtopping discharge were formulated for which scale effects are negligible.