{"id":1574,"date":"2011-06-09T20:35:55","date_gmt":"2011-06-09T20:35:55","guid":{"rendered":"http:\/\/www.joswassink.nl\/insight\/?p=1574"},"modified":"2011-06-09T20:35:55","modified_gmt":"2011-06-09T20:35:55","slug":"a-pretty-optimal-choice","status":"publish","type":"post","link":"https:\/\/www.joswassink.nl\/insight\/?p=1574","title":{"rendered":"‘A pretty optimal choice’"},"content":{"rendered":"

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NRC Handelsblad<\/p><\/div>\n

The advisory committee for the future of the Afsluitdijk presented its final report last week. The iconic dike between IJsselmeer and Waddenzee will not be made higher, but more solid, as the Dutch newspaper NRC Handelsblad reports.<\/strong><\/p>\n

Professor Han Vrijling (Civil Engineering and Geosciences) was ‘a little amazed’ by the chosen option. Rijkswaterstaat had made a shortlist of four renovation proposals submitted by various consultancies and consortia in response to a tender four years ago. There were designs with concrete storm shields, with nature reserves on either sides of the dike, energy plants running on osmotic power, and a storage lake for hydropower. Vrijling and his team were asked to make feasibility studies for the shortlisted designs. When he saw them, Vrijling declared: \u201cThis is the end of an era. We’re so rich that we cannot simply renovate a dike without attaching a fancy ecological or sustainable solution to it.\u201d Still, the group wasn’t asked for comments, just for an assessment of the feasibility of each of the plans. They all got green light from Vrijling. But come the day of the final report and yet another design emerged as the winner \u2013 a design that was in fact not on the shortlist.<\/p>\n

The graphics show that the dike will be reinforced on the inner side and that the inner slopes will be made less steep. The idea behind this is that if waves overtop the dike, the water rolling down the other side will not cause damage.<\/p>\n

\u201cYou want to prevent breaching of the dike,\u201d explains Professor Marcel Stive (CEG). \u201cThat is what happened in Zeeland in 1953: water overtopping the dike eroded the inside of the dike, resulting in an opening through which the water rushed in.\u201d Shortly after that disastrous flood, engineer Ton Edelman proposed to modify the dikes to make them resistant to overtopping water.<\/p>\n

Despite its simplicity, Edelman’s plan has not yet been put into practice, except for an exceptionally broad multifunctional dike in Maassluis. Notwithstanding its invention more than half a century ago, an overtopping resistant dike can be called pretty innovative, says Stive, who called the committee’s recommendation \u201ca pretty optimal choice.\u201d And yes, it was the cheapest option as well. Originally, before the crisis hit, the previous Cabinet reserved 750 million euros for the makeover. The budget has now been reduced to 600 million. Prof. Stive is glad that the sober character of the Afsluitdijk will remain unchanged. \u201cA straight line on the map and through space,\u201d he calls it. And as an active bicyclist he appreciates the fact that the bicycle path will be constructed between the southern car lane and the IJsselmeer, instead of between the motorway and the dike top. \u201cThe noise and pollution is probably less, and the view is better because you’re nearer to the water.\u201d<\/p>\n

\u201cIt’s the wisest decision,\u201d Vrijling agrees. In fact, he already expected the committee to opt for a cheaper and less ambitious alternative. Having had no detailed information of the plan, he now must rely on drawings in the newspapers, which leaves him wondering how exactly they plan to make the dike resistant to overtopping water. \u201cThe first inner slope and the crease at the end of it need to be resilient enough. Soil-mechanically speaking, that is not very simple to achieve.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"

The advisory committee for the future of the Afsluitdijk presented its final report last week. The iconic dike between IJsselmeer and Waddenzee will not be made higher, but more solid, as the Dutch newspaper NRC Handelsblad reports. Professor Han Vrijling (Civil Engineering and Geosciences) was ‘a little amazed’ by the chosen option. Rijkswaterstaat had made […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3,6],"tags":[34,207,274],"class_list":["post-1574","post","type-post","status-publish","format-standard","hentry","category-articles","category-delta","tag-afsluitdijk","tag-han-vrijling","tag-marcel-stive"],"_links":{"self":[{"href":"https:\/\/www.joswassink.nl\/insight\/index.php?rest_route=\/wp\/v2\/posts\/1574","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.joswassink.nl\/insight\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.joswassink.nl\/insight\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.joswassink.nl\/insight\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.joswassink.nl\/insight\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1574"}],"version-history":[{"count":0,"href":"https:\/\/www.joswassink.nl\/insight\/index.php?rest_route=\/wp\/v2\/posts\/1574\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.joswassink.nl\/insight\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1574"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.joswassink.nl\/insight\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1574"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.joswassink.nl\/insight\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1574"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}