The 1953 flood disaster prompted a new approach to the design of dikes and other water-retaining structures , based on an acceptable probability of overflowing . Risk is defined as the product of probability and consequences . The potential damage in lives , property and rebuilding costs is compared to the potential cost of water defences . From these calculations follows an acceptable flood risk from the sea at one in 4,000 – 10,000 years , while it is one in 100 – 2,500 years for a river flood . The particular established policy guides the Dutch government to improve flood defences as new data on threat levels becomes available . Some famous Dutch polders and the year they were laid dry are : The Markerwaard is the name of a proposed polder in the IJsselmeer that was never built . The construction of Markerwaard would have resulted in the near-total reclamation of the Markermeer . Markerwaard was expected to be finished in 1978
1953 flood disaster
North Sea flood of 1953
Land reclamation in the Netherlands