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ATTIYA REHMAN

Assessing coastal defence schemes

Sheringham is a seaside town in Norfolk, England, west of Cromer with a population of 

7,143. On the coast the wind blows the waves from a north east direction. This is direction

of the cold northern seas and oceans, e.g the Norwegian sea and the arctic ocean. Suchstrong waves carry large amounts of energy, and easily erode away the soft boulder clays of 

the coastline. The cliffs of Sheringham are made of soft sandy material deposited during the

Ice Agea and therefore are vulnerable to erosion. Sheringhams beaches not only suffer from

coastal erosion and different types of weathering but also from long shore drift. Longshore

drift is a process that moves sediment from the beach up a coastline.

The coastal protection on the Sheringham coastline includes seawalls and groynes. The

storm surge of 1953 damaged Sheringham’s wooden sea defences so they were then

reconstructed. In front of the sea wall are groynes, armoured at their bases with large

blocks of natural rock, which prevent long shore drift. There are numerous drains along the

frontage. To the east towards West Runton the seawall ends just below Beeston Bump.

From there a timber revetment and groyne system, designed and constructed in 1976, runs

eastwards for 2 km (just over a mile) to West Runton Gap.

In the latest coastal protection scheme, there was the repair and renovation of 900 metersof the existing sea walls and the placing of large rock armour stone in front of them to act as

There is evidence of cliff slumping along

the Sheringham coastline caused by

powerful destructive waves

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buttresses and to absorb the energy of the breaking waves. This Stage of the project was

completed in 1995 at a cost of £3.4 Million.

The second stage works involved a lot of work on the groyne system at Sheringham. All five

of the old timber groynes at the west end from the Lifeboat Station to the Admiralty Slip

were renewed or replaced with new timber groynes and an extra groyne was built.

These sea walls and groynes have been recently reconstructed or build and sea walls have a

typical life span of 50-75 years and groynes up to 40 years. This shows that they are still in

good shape and can continue to protect the coast. However tourism is high in Sheringham

so the groynes may be damaged a lot more so may last a shorter time than expected. Sea

walls aren’t very attractive so they have large visual impact on the environment which may

in turn affect the tourist industry as people wouldn’t visit coasts that are unattractive.

Sheringham: SEA WALLSNegative evaluation factor -3 -2 -1 1 2 3 Positive evaluation factor

Vulnerable to erosion X Effective protection against erosion

Vulnerable to overtopping X Effective against overtopping

Ugly (poor aesthetic value) X Enhances natural environment

Poor access to beach X Good provision made for access to

beach

High risk safety hazard to general

public

X No obvious safety risk to general public

Short life span. High maintenance

costs

X Good life expectancy/ low maintenance

costsHigh levels of disturbance caused to

local people during construction

X Low levels of disturbance caused to local

people during construction

Disturbs natural coastal processes

and habitats

X Maintains natural coastal processes and

habitats

Total value: -1

Protection is being given to the highest value areas i.e. where cliffs have soft rock and are

most vulnerable to erosion and transport of sediment along the coast. The shoreline

protection in place – sea walls and groynes prevent the erosion of cliffs and land at the rightareas.

Protection

Technique

Approx cost Total length

used

Total cost Typical

lifespan

Concrete sea walls £2500 per metre 1,800 (m) £4500000 50-75 years

Groynes £20,000 each 5 used £100,000 25-40

Overall I think groynes are more cost effective as they don’t cost that much and have quite a

long life span. They are effective at preventing longshore drift along the coast. If these werenot in place, sediment would be transported up the coast. Sea walls are also quite effective

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and can last up to 75 years. Even though the initial cost is high, they are really effective at

preventing coastal erosion. If they were not in place, many houses and buildings along the

coast can be destroyed effecting people socially and economically as they would have to

find a new place to live and have high insurance costs on their homes.

The scheme is meant to stop coastal erosion and longshore dift. Effective management

schemes have been put in place to prevent this and to slow down coastal erosion.