Keynote lecture: Flood defense in The Netherlands: a new era, a new approach

Intensive land use and far-reaching alterations to the fluvial hydrosystem, made feasible by technological developments in the past century, have reduced the hydromorphological resilience of the Rhine and Meuse river basins. Because the hydromorphodynamic processes could be controlled to a greater extent, residents of the riverine areas lost their sense of the natural dynamics of river systems, and further urbanization of areas prone to flooding took place without the potential dangers being recognized. It was particularly in the low-lying polders of The Netherlands that the potential damage from flooding increased tremendously over time. The Dutch Ministry of Transport, Public Works and Water Management is currently trying to achieve sustainable water and river management by developing and implementing a new approach to flood defense. In addition to the implementation of technological measures, the government aims to create more space for the rivers, combined with objectives from other policy areas, including the reconstruction of rural areas, development of the ecological infrastructure, surface mineral extraction, land use and other area-specific projects such as housing schemes. This approach is not confined to The Netherlands: similar concepts have recently been introduced at various other locations in the Rhine and Meuse river basins. The new approach requires land-use changes and introduces new scientific research issues relating to land and water use, hydromorphology, river management and socio-economics. This paper discusses this new approach and related scientific developments.