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The Hillblock revetment reducing the risk of flooding to the coastal community of Stolford, Photo by Gov.uk

Engineering first as Dutch flood defence scheme is unveiled in Somerset

The tiny coastal community of Stolford has become the first location in the UK to benefit from innovative flood defence technology pioneered in Holland.

Overlooking the Bristol Channel, Stolford has a history of coastal erosion and is prone to flooding. In 1981 high tides overtopped sea defences and flooded 660 hectares of land including 24 properties. Livestock also died. In 1990 a high tide and storms caused further flooding.

There are already coastal defences between Stolford and Hinkley comprising of rock armour and an embankment wall. These defences adjoin a shingle ridge that was prone to serious erosion.

Rising sea levels and more extreme weather conditions have made the ridge and embankment increasingly vulnerable to erosion and increased the risk of a breach. The Environment Agency previously spent £50,000 a year replenishing the ridge with 15,000 tonnes of shingle.

Conventional rock armour, also known as rock revetment, would have been too costly and visually intrusive. In addition, the transportation of rock armour would have caused excessive disturbance from heavy lorries travelling in narrow lanes to a remote coastal location.

It was decided the best solution was a Dutch system known as Hillblock, a type of block revetment, that uses a series of specially-shaped concrete blocks. Storm waves flow over the structure and enter a network of cavities between the blocks that absorb wave energy.

Shaped like champagne corks, the blocks are made from high density concrete and held in place by steel piles and concrete kerbs. Although extremely heavy, each block is designed to move slightly. The technology has been used extensively in coastal defences in Holland.

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