Modelling dike breaching due to overtopping

Dikes along rivers protect a valley and its people and property from floods. Recent dike failures due to overtopping highlight the need to understand this damage process. Its accurate prediction is essential to develop effective emergency action plans and to design early warning systems and hazard maps. Laboratory tests of breach processes are related to scaling issues currently not understood. Therefore, a series of plane dike breach tests due to overtopping were conducted to examine model limitations. All dikes were of trapezoidal shape, consisted of uniform noncohesive sediment and neither contained a core nor a surface layer. The temporal dike breach progress was optically recorded to allow for a detailed analysis of the sediment and water surfaces. A systematic variation of both the dike dimension and the sediment diameter resulted in basic findings relative to: (1) Test repeatability; (2) Side wall effect; and (3) Scale effects. The results indicate definite minimum dimensions for both the dike height and width, sediment diameter and overtopping discharge.