Adapting to Climate Change in Urban Water Management: Flood Management in the Rotterdam

Adapting to Climate Change in Urban Water Management: Flood Management in the Rotterdam–Rijnmond Area

van Vliet, M. / Aerts, J. C. J. H.

Many large coastal cities are located in deltas, which makes them vulnerable to floods. In many cities flood damage has increased due to increases in population and assets, and this process is expected to continue. At the same time, climate change will cause floods to occur more often in many rivers and deltas due to higher discharges and sea level rise. These trends call for the development and implementation of new technologies and strategies in flood risk management. This call is also acknowledged in the Netherlands, a country that has a strong history of relying on structural measures. The city of Rotterdam includes many unembanked areas, large parts of which will be redeveloped in the near future. Current practice is to elevate all unembanked areas to a 1 in 4,000 years flood level. This is not only very costly, but also causes problems when an area is redeveloped in phases, or when existing buildings will remain as both cause unwanted elevation differences and differences in flood protection. Rotterdam is therefore looking for adaptive (non-structural) measures to decrease flood damage in these areas. Such measures are presently little used in the Netherlands. One key question is how these new measures fit in within current policies, laws, and regulations in Rotterdam. This chapter describes measures studied for a case study area in Rotterdam, gives an analysis of the policies, laws, and regulations relating to these measures, and examines the implications for urban flood management. Our research shows that, in principle, the rules do allow for implementation of adaptive measures. It is, however, problematic how these measures can be enforced, and this weakness can cause problems, e.g. when not all waterfront buildings are dry-proofed. Better communication of flood risks is recommended, as this will increase awareness and preparedness, which in turn might lead to a higher implementation rate of adaptive measures.