ATTIYA REHMAN Assessing coastal defence schemes Sheringham is a seaside town in Norfolk, England, west of Cromer with a population of7,143. 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. Such strong waves carry large amounts of energy, and easily erode away the soft boulder clays ofthe 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 meters of 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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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
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