A multi-layer flood safety approach towards resilient cities

The multi-layer safety approach focuses on flood risk reduction through three types of measures: (1) prevention through dikes, levees and dams , (2) a flood resilient spatial planning and (3) an adequate crisis management. Whereas the official Dutch policy propagates the multi-level safety approach, the current Dutch water safety policy is still focused on prevention only (layer 1). The integration with the two other layers (i.e. a flood resilient spatial planning and an adequate disaster management) has still to be explored. In order to assess the technical and the organizational feasibility of the multi-layer safety approach in urban areas, the Province of North-Holland and the Waterboard Hollands Noorderkwartier have initiated a case study. In this case study various stakeholders of a pilot area were invited to discuss about the opportunities of the multi-level safety approach. The case study and accompanying workshop showed that an integration of the different policy layers (i.e. dike reinforcement, spatial planning and disaster management) adds much complexity to the decision environment of the stakeholders, both in technical and organizational terms. A first requirement of the stakeholders involved in such decisions was understandable information about flood risks and an integration of flood risk information with the different policy fields of spatial planning and flood disaster management. The applied 3D visualization and high detailed 2D inundation model was highly appreciated to provide this information.