Author(s)

E. Pasche, G. Ujeyl, D. Goltermann, J. Meng, E. Nehlsen & M. Wilke

Abstract

In consequence of the climate change, a sea level rise within the coming decades is highly probable and the intensity of storm surges will probably increase at least in the North Sea region. In this changing environment, great uncertainty exists about the need to adapt conventional coastal flood protection structures. This calls for response strategies to improve the flood resilience behind the dikes, in the Hinterland. Within this paper, the concept of cascading flood compartments is presented as an appropriate strategy to deal with the residual risk in the Hinterland. The key element of this approach is that an overtopping of the main dike line is accepted requiring their enforcement to resist erosion from hydrodynamic loads. Inner dikes are arranged in a multi-layer cascade of compartments creating a redundant system of flood containment. The necessary adaptations and restrictions to the built environment vary from simple resistance measures of dry- and wet-proofing to the development of amphibious settlements with floating homes and houses on piles. The whole concept is illustrated on the island of Wilhelmsburg in Hamburg, where urban areas are protected against storm surges through a ring dike. The necessary storage capacity of the flood compartment system is determined for the climate change scenarios of 2030 and 2085. A realistic arrangement of flood compartments can be found, proving the effectiveness and efficiency of this response strategy. 3d graphics illustrate the transfer from a water-abandoned city to an amphibious city, backing the statement that this flood response strategy opens new opportunities for cities. Keywords: climate change, flood risk management, cascading flood compartments, flood response strategy, amphibious cities.

Keywords

climate change, flood risk management, cascading floodcompartments, flood response strategy, amphibious cities.