Flood damage reduction by compartmentalization of a dike ring: comparing the effectiveness of three strategies

Compartmentalization of dike ring areas is currently seen as one of the promising options for managing or reducing the risk of flooding. Recently, several studies on the effectiveness of subdividing dike ring areas by means of compartmentalization dikes were published. These studies show that the total damage after a flood could indeed be smaller, but that the damage could also turn out to be larger on a local level. The available studies on compartmentalization usually consider only one dike pattern in the area concerned. This article develops, assesses and compares three fundamentally different strategies, based on different configurations of the compartmentalization dikes. Not only do we examine the effects of the most probable flood scenarios, we also look at the worst-case scenario, whereby the water is able to flood into the dike ring area from all sides. The spatial layout of the area codetermines the effectiveness of each strategy. Dike ring area 14, which lies in the west of the Netherlands and that covers some cities, like Amsterdam, Rotterdam and The Hague, was chosen as the area of application. The results show that for this dike ring, the secondary dike strategy is most effective in reducing the number of expected victims under different flood scenarios.