Science - September 16, 2004

Dutch may lose fight against the sea

It is well known that the Dutch are masters at building defences against the sea. What is less known is that wood worm from the Indies and German bombs at different points in history did a great job at destroying those defences, and that the sea is steadily becoming a more dangerous threat to the Netherlands. Dr Jan Bieleman highlighted these issues in the first of series of lectures for foreign students about the Dutch fight against the elements.

In his lecture last Wednesday lunch time Bieleman, originally a landscape architect but now teaching and doing research at the Agricultural History group at Wageningen University, started by acknowledging the excellent achievements of the Dutch in their struggle to control the sea. The culmination of these efforts is the Delta Works, a series of giant dams along the coast of Zeeland. ‘We can now defend ourselves against a storm surge like the one that happened in 1953 in which a large area of the Netherlands was flooded.’ But, warned Bieleman, the Dutch should not get too complacent.

There are lessons to be learned from history. The threat from the sea became greater at times through their own fault. Bieleman: ‘For example in the eighteenth century we still had wooden sea dykes, and many of them were destroyed. How did it happen? In 1731 a wood worm attacked the dykes, and it turned out we had carried the wood worm by ship from our colonies in the East Indies.’

Bieleman went on to recount other bad surprises to the interested audience which included Americans, Spanish and Chinese MSc students. ‘The Dutch had been draining and reclaiming large areas of land and building dams around them for many years, when in 1945 the Germans, who were losing the war, bombed a big dam in the north of the country which had just been recently completed around the Wieringermeerpolder. The land was flooded again in no time.’

Nowadays the war is largely forgotten, and modern technology enables the Dutch to build dykes that will last for centuries, but Bieleman pointed out another weak point. In their enthusiasm to drain the land, creating space for so many people, the Dutch may be creating an insoluble problem. ‘In our polders that used to be lakes, like the Haarlemmermeer where Schiphol is located, the land lies below sea level, so groundwater has to be pumped out continuously to avoid flooding. This pumping, however, compacts the clay soil and means the land is becoming lower and lower, making pumping more and more intensive. We have to find a way to stop this process, but this will not be easy. And we also need to think about the rising sea level due to global warming. We are in a very vulnerable position,’ said Bieleman. In the hope that the Netherlands will not become totally submerged in the long run, the historian tries to take a glimpse of the future. ‘We may eventually need an enormous dam, like the Delta Works, but stretching along the entire Dutch coast and extending into German and Belgium. And we may have to give up the northern Wadden Islands to the sea.’ / HB

The last lecture in the series will be held on 22 September, Imag building, Mansholtlaan 10, Room C67, 12.30 – 13.10.
There will be excursions on 24 September and 2 October.
info: www.wau.nl/sg

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