Signed, Sealed, Delivered

Maintaining the integrity of sea defences along the UK’s Norfolk coast is essential to prevent flooding of thousands of acres of rich farmland along with habitats for rare plants, birds, reptiles and small mammals – but it’s an ongoing battle

Following a massive breach of those defences during the disastrous floods of 1953, which caused the loss of many lives, the coast has been further protected over the years with artificial reefs, beach replenishment projects, the rebuilding of seawalls and construction of groynes.

Time, however, takes its toll and the government organisation responsible, the Environment Agency, regularly calls for tenders to renew and replace decaying defences. The latest such scheme extends along an 18km stretch of beach between Happisburgh and Winterton that needed new groynes, a new revetment at Eccles and beach replenishment at Sea Palling.

The contract went to marine and coastal engineering specialists Abeko UK in partnership with Team Van Oord, the latter providing technical support and the beach replenishment. Quantities of material supplied included 35,000 tonnes of fresh granite rock, an estimated 25,000m³ of sand-buried rock, plus 280,000m³ of dredged sand for beach replenishment.

Scope Of Work

The project involved removing 10 badly deteriorated 80m-long timber groynes, which meant excavating to the clay level and then pulling out the old timbers. And because some parts of the groynes were still partially submerged at low tide, the contractors had to wait for low springs to gain access.

The timber was replaced with much more substantial rock armour groynes, to the same 80m length. With the old groynes removed, the beach was levelled and excavated down to clay – with care taken not to damage the existing concrete stepped seawall, which had been covered by sand over the years.

Care was also needed throughout the excavations as the Environment Agency wanted to minimise disturbance of the clay bed. Built at 90o to the beach, the first 8m was level, after which it followed the natural slope of the beach.

Once the excavation had been measured and approved, a 6m-wide geotextile bed was spread and a base line of three granite boulders – measuring 1.5–2m diameter and weighing 10–15 tonnes – was put in place across the widt ...