When the massive earth-moving machines drive along the crest of the historic King Christian X's Dike between Vester Vedsted and the road-carrying dam to the island of Rømø, the ground gives by several centimetres. Several days of incessant rain have rendered the sub-base soft and slippery, making it difficult for COWI project manager Steen K. Nielsen to keep his footing on the crest of the dike.
Several times a week he and his colleagues from the supervision staff pull on their boots and go on-site to check the composition of adhesive clay and sand, that there are no clumps which could cause cracks in the dike and that the earth is sufficiently compact.
After weathering 80 years of storms, King Christian X's Dike and Ballum-Astrup Dike, which form a 16 km long barrier between the Wadden Sea and the fields behind the dikes, are being renovated and reinforced. At the same time, the slope of the dike is being modified and three sluices in the area renovated. Nature can sometimes show its teeth, particularly in winter when strong winds press the sea in towards coastal areas. In extreme weather the waves can rip holes in the grass covering the dikes or break them and flood the fields.
A survey carried out by the Danish Coastal Authority in the late 1990s which proved that the dikes would not be able to withstand another 50 years of storms – as required by the Storm Flood Committee – sounded the alarm, and work got under way on a major dike reinforcement project. The project means that plot owners whose land adjoins the dikes will retain their right to compensation in the event that their property or land are flooded.
In addition, the dikes will be better able to withstand rises in sea level of up to 60 cm, as is forecast to occur this century by climate researchers. This problem of rising sea levels will also have to be taken into consideration when planning future building and construction projects.
"This is an interesting project with many facets and challenges," says 41-year-old Steen K. Nielsen, who is responsible for inspection and construction management. "We have only limited experience to draw on from similar projects. Plus it requires a tremendous logistical effort to remove such large quantities of earth. We are adding to the dike a total of 475,000 m³ of sand and adhesive clay, and moving a further 75,000 m³. That is the equivalent of about 70 football pitches to a depth of one metre. All in all, this is a major project that will cost in total DKK 47 million." The project is being financed by the Ministry of Transport, the counties of Southern Jutland and Ribe, the municipalities of Skærbæk, Ribe and Bredebro, and the dike owner associations Digelaget for Kong Chr. X's Kog and Digelaget for Bredeådalen. COWI, the principal consultant for the project, is carrying out the work for the dike owners. By Christina Tækker, cht@cowi.comPosted: 27.10.2004