New coastal protection defends Anholt’s precious coastline

12.06.2019

The islanders and the many tourists visiting the picturesque Danish island Anholt can look forward to a summer with improved beach conditions and a safer coastal road. The new coastal protection is in place and will together with proper beach nourishment reduce erosion and protect the coast for many years to come.

June 8th, 2019 was a big day for Anholt, one of Denmark’s most secluded island communities: the islanders inaugurated a new coastal protection solution to stop the erosion of their beloved island.

The new structures can withstand the heavy seas rolling in from the North and the islanders should no longer have to worry about vanishing beaches or destruction of the coastal road caused by storms.

The new coastal protection elements have also improved bathing safety and recreational possibilities – making activities like snorkelling, fishing, windsurfing and kitesurfing more accessible for the joy of both the inhabitants and the visitors.

Optimal protection against the waves

Many Danish coastlines struggle with erosion and risk of flooding caused by waves and rising sea levels. For Anholt, the turning point came after a fierce November storm in 2011 when the islanders woke up to a main road that was washed away.

The road had been exposed to years of wind and wave erosion, and more sand was being removed by erosion than brought in by waves and current. Anholt’s northern coastline has retreated more than 30 metres over the past 20 years and something had to be done.

COWI got involved in early 2013 to investigate the coastal protection scenario and came up with a concept based a few large coastal protection structures. The new coastal protection elements consist of slope protection, a groyne and three breakwaters, providing the island with optimal protection against the waves.

Reducing erosion of coast line

The slope protection protects the coastal road while a sand dune conceals the structure and allows the beautiful beach to maintain its natural look.

Off the coast, three breakwaters break the waves before they reach the shoreline, meaning that less wave energy is released onto the shore, causing less erosion.

Jens Bundesen, Coastal and Climate Adaptation Engineer at COWI explains:

“This construction allows the deposition of sand to form a bar between the breakwater and the coast. In addition to the breakwaters, a groyne is placed perpendicularly to the coast, capturing sand and further reducing erosion. Together with beach nourishment maintenance, the combination of the coastal protection elements will protect Anholt’s coast for many years to come.”