Details of the Dutch government’s latest controversial plans to keep the country safe from rising sea levels and river flows over the next century are reported in the latest issue (164, CE3) of ICE’s Civil Engineering journal.
A team of eminent authors led by Marcel Stive of Delft University say the Netherlands’ Delta committee’s latest recommendations are feasible both technically and economically, and could be applicable to other low-lying areas.
The proposed programme of work will cost the country up to €3 billion a year – around 0.5% of its gross national product – and is based on a gradual upgrading of safety standards in the light of potential economic growth, changing group casualty risk and uncertain climate change.
Over two thirds of the Netherlands’ economy and half its population is below sea level. Protection is provided by 53 ‘dyke rings’, the failure of which could result in economic losses of €10–50 billion per ring. Rather unusually, mandated flood safety levels vary from 1:10 000 for rings around rich, economically vibrant area such as South Holland to just 1:1250 for those protecting poorer, more rural areas.
Stive says implementing the latest recommendations will require a paradigm shift in the Dutch approach to water and coastal management. ‘Whereas in the past the challenge was formulated to fight the forces of nature, it is now recognised that many issues other than protection against flooding have to be accommodated – particularly ecological issues.’
Recommendations include increasing flood-protection levels tenfold by 2050, maintaining coastal defences with beach nourishment as required, modifying the Eastern Scheldt storm-surge barrier for a sea-level rise of up to 1m, making room for greater Rhine and Meuse flood flows and raising Ijsselmeer lake levels by 1.5m.
For further information please contact the ICE Proceedings editor Simon Fullalove on +44 (0)20 7665 2448 or email editor@ice.org.uk.