How can the Netherlands adapt to sea level rise on the long term: maintain, advance or retreat? This article compares the results of seven plans and designs from a diverse group of scholars and professionals that offer very different answers to this question. This diversity broadens the options, which is vital in this stage. Both problem solving and design approaches are shown to be worthwhile, when grounded in coastal, landscape, and ecological dynamics as well as visions of the Netherlands in the far future.@en

A breach in a flood defence will affect the downstream water levels in a riverine system, and therefore the flood risk of the system. The effect of this changed flood risk is used in an economical optimization to assess if this significantly changes the economically optimal safety targets of the flood defences in a riverine system. The impact of breaches on the flood risk and the economically optimal safety targets is modelled using simplified hydrodynamic relations and a number of conceptual case studies for small systems. Significant differences were found, but are limited to cases with a relatively high chance of breaching and/or high impact breaches. These differences seem to mostly affect the optimal heights of the flood defences, which means that including the effect of breaches can result in a different-optimal investment path.@en