Simulation of flood wave propagation due to dike failures on the German Baltic Sea coast

This paper shows results of applications of a numerical model to the simulation of flood wave propagation due to a dike–break and a dike–overtopping events on the German Baltic Sea coast. The simulated domain is a small coastal area near the town of Zingst on a narrow peninsula that separates the Baltic Sea from a chain of lagoons. Simulations were carried out for the conditions observed during the 1872 severe storm which caused major damage to the entire coast. An improved two–dimensional finite–element model based on the solution of a non–conservative form of the shallow water equations using a combination of shock–fitting and through methods was used. The results demonstrate the effectiveness of the model in handling shock waves emerging from ruptured and overtopped dikes and thus to assist in the preparation of flood emergency and dike break action plans. The most important processes observed during the events were well captured by the model. They include the shape and evolution of the wave front, wetting, different levels of overtopping and the presence of mixed supercritical and subcritical flows with hydraulic jumps.