Protecting the Danish North Sea Coast
The mainland of Denmark is a low-lying peninsula that juts out 300 km into the North Sea from northern Germany, and the North Sea coast is a landscape of estuaries, inlets, low cliffs, dunes and long sandy beaches.
According to Per Sørensen, Head of Coastal Research at the Danish Coastal Authority, “People here have always depended on the wide beach and coastal dunes to protect them from the sea. But the coast here has always been in retreat, causing communities to move further inland in a never-ending cycle.”
The traditional remedy was to build groynes – sand catchers jutting out from the shoreline – to trap and hold some of the eroded sand.
Per continued: “From 1874, they brought massive quantities of rock here and placed them perpendicular to the coast, but the erosion has continued all the same. I know a family that has farmed in Krogen for five centuries, and the homestead has had to move further inland twice in that time. Today there is just one row of dunes protecting the settlement from the sea.”
A new approach was called for. Following severe flooding in 1981 due to a breach of the dunes, the coastal municipalities and the Danish state agreed in 1982 to manage coastal protection jointly, with 5-yearly reviews, national funding, and a focus on research.
“From that time on, we have taken a more holistic approach,” said Per Sørensen. “In 1974, the first trials had been conducted with a Nature Based Solution: the use of sand nourishments in the surf zone and on the beach to make the high water shallower during storm surges, so that wave energy is dissipated before it reaches the dune face. This approach was so successful, that since 1992 it has become the primary means of coastal protection on long stretches of the North Sea coast.”
So by building with nature – “going with the flow” of the wind and water – the Danish Coastal Authority now has a nature based tool for coastal defense that can easily adapt to the needs from season to season.
By closely monitoring the changes on the beach and in the dunes, they can apply nourishments when and where the need is greatest while continuing to strengthen the natural barrier.
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