Dike reinforcements in Zeeland
Projectbureau Zeeweringen is reinforcing the dikes of Zeeland. The cladding of many dikes along the Oosterschelde and Westerschelde is not strong enough. In case of a so-called superstorm, some stones and concrete could break away. Reinforcement is necessary to protect Zeeland and other parts of the Netherlands against flooding.
Projectbureau Zeeweringen was established in 1997 and is a partnership between the Department of Public Works and the water board Scheldestromen. In 2015 a total of 325 kilometres of dike will have been reinforced. At the moment, about half the work has been completed.
Superstorm
The stone cladding of a dike should be strong enough to safely stem the waves of a superstorm. The Flood Defence Act regulates the sturdiness of dikes and stone cladding. The standard depends on the damage a storm can cause in an area. In Zeeland the safety standard is 1:4000. This means that a dike should be able to withstand a superstorm, which on average happens once every 4000 years. By way of comparison, statistically the North Sea flood of 1953 happens once every 250 years.
Stone cladding
The foundation of a dike is made of sand. In order to prevent that the foundation is washed away, it is covered in a layer of clay and filter material, upon which a layer of stone or concrete is applied, which is sometimes cast in asphalt. This stone cladding fends off the worst beating of the waves. Modern stone cladding consists of a construction made of concrete or quarry stone. In the past, many stone and concrete types were used that are no longer considered heavy enough. Projectbureau Zeeweringen replaces or reinforces this cladding. Where possible, concrete blocks are reused by turning them into an upright position.
Tight schedule
Many dike sections have been added to the workload in the past few years, but the 2015 deadline is fixed. The project office is therefore working on a very tight schedule. Every year, about ten dike sections are under construction. The work takes place between 1st April and 1st October. The rest of the year is considered storm season during which dikes must not be broken up.
In addition about 25 other dike sections are also prepared and completed each year. This includes the making of an inventory of the dikes' flora and fauna, technical testing, permit applications, design, contract and maintenance.
Various interests
Planning work on individual dike sections is also challenging because of many, often conflicting interests. People, plants and animals all require special attention. Work on a dike can only take place during six months on the year. During this period plants flower, birds nest and people spend their leisure time near the dikes. For example: a campsite owner obviously prefers all work to be completed before the start of the tourist season. But sometimes it is not possible to start working so early in the year because of nesting birds. Situations like this require a lot of consultation and good synchronisation with all parties involved.
Know more
Should you like additional information to know more about the exact schedule of the project office's activities or if you have another query, please contact us by sending an e-mail to info@zeeweringen.nl.
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