Site-Name

Wells next the Sea

Wells next the Sea

Client

Environment Agency

Introduction

The Environment Agency completed the £1.1 million Wells and Burnham Overy Staithe Tidal Defence Scheme in 2001. Much of the work involved the installation of 12,000 m² of Armorflex concrete revetment blocks on the Wells West Bank, which runs from the north of the town to the Lifeboat Station.

Problem

These defences were last breached in 1978 when extensive flooding to the environmentally sensitive marshes occurred, so special measures had to be taken to avoid any harmful impact on the protected species of flora and fauna that are present in the area. Wells is a popular seaside resort and pedestrians walking along the crest of the embankment away from the designated footpath had caused serious erosion to the grass surface on the West Bank.

Construction

The crest of the embankment has been increased to ensure a consistent flood defence level. Armorflex 140S mattresses (100mm thick) extend from the toe of the existing embankment up the bank to the crest. On the crest, where most pedestrian activity takes place, the normal Armorflex 140 mats (85mm thick) were installed. Together this system provides erosion control against the ravages of the sea and also protects the bank from damage caused by the many pedestrians who walk along the grassy crest making, what is in effect, a concrete reinforced grass walkway. To prevent the fine material from being removed from under the Armorflex during high tides, a woven geotextile was laid on the profiled surface before the mattresses were laid on top. Other improvements have also been made for the public including access ramps for the disabled, additional steps to the top of the bank and new bench seating.

Conclusion

Armorflex is an environmentally friendly green system. The type of Armorflex specified contains two holes in each of the blocks so that when these are filled with topsoil and seeded, a cover of grass will establish in the voids. The Wells tidal defence system will appear fully vegetated, blending in with the surroundings and providing. completed 2000.


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