34 Flood Defence ’2002, Wu et al. (eds)© 2002 Science Press, New York Ltd., ISBN 1-880132-54-0 Keynote lecture: Flood defense in The Netherlands: a new era, a new approach H.T.C. van Stokkom Ministry of Transport, Public Works & Water Management, Division East, Gildemeesterplein 1 6800 ED Arnhem, The Netherlands, E-mail: h.t.c.vstokkom@don.rws.minvenw.nl A.J.M. Smits University of Nijmegen, Nature Conservation of Stream Corridors Toernooiveld 1, 6500 GL Nijmegen, The Netherlands Abstract: 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. Keywords: sustainable flood defense strategies, hydromorphology, habitat restoration, socio-economics, public-private enterprises. 1. INTRODUCTION Located in the delta formed by the Rhine and Meuse rivers, The Netherlands has a long history of adapting the natural water and river systems to user functions such as housing, agriculture and shipping. Fig 1 provides an overview of the Rhine and Meuse river basins. The “everlasting fight” against floods in this small country, much of it situated well below sea level, is legendary. Large parts of The Netherlands are still subsiding, while the sea level is rising. Approximately 25% of the country is currently situated below mean sea level (by up to 6.7 m). Without the dikes and dunes along the coast, 65% of the most densely populated part of The Netherlands would be flooded every day. Huisman et al. (1998) presented a historic overview of geographic and hydrological aspects of The Netherlands and described the organizational and legislative developments of water management. Originally, the water boards, Netherlands oldest democratic institutions, took care of flood protection and land reclamation. However, the water boards tended to focus on regional interests, which frequently led to controversial management measures and sometimes to