AQA AS Geography Coasts: Hard Engineering Coastal Defences

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  • Created on: 22-08-13 20:28
Preview of AQA AS Geography Coasts: Hard Engineering Coastal Defences

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Hard Engineering Coastal Defences
Defence How it works Advantages Disadvantages Example
The wall reflects waves Prevents erosion of the A sea wall is expensive to In Minehead, millions of
Sea Wall coasts and prevents flooding. build. It requires regular pounds have been spent on
back out to sea,
preventing erosion of the maintenance. Curved sea rock armour and sea walls.
coast. It also acts as a walls reflect the energy of This is to protect the tourist
resort of Butlins, which is
barrier to prevent the waves back to the sea.
important to the local
flooding. This means that the waves
economy. Porlock, owned by
remain powerful. Over the National Trust, is
time the wall may begin to managed very differently. A
erode. shingle beach protects the
settlement, but recent winter
gales have overwhelmed this
ridge and the land has
Revetment Revetments are slanted Low-cost solution for They create a strong
structures built at the foot coastal erosion defence in backwash which erodes
of cliffs. areas where crashing under the revetment.
They can be made from waves may otherwise Strong landscape impact.
concrete, wood or rocks. deplete the coastline. Can alter dune system
Waves break against the Good long-term permanently as sand tends
revetments, which absorb protection. Can be not to build up over the
the wave energy and so extended or modified to rocks if beach erosion
prevent cliff erosion. allow for future shoreline continues
change. Unlimited
structure life.

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Riprap Boulders piled up along The size and the mass of Can shift in storms. Le Croisic, Brittany
the coast are called the riprap material They also can be quite The houses are protected
riprap. absorbs the impact energy ugly, changing the from the sea by rip-rap -
The boulders absorb wave of waves, while the gaps appearance of a coastline. large boulders of resistant
energy and so reduce between the rocks trap The boulders must be rock brought from outside
erosion.…read more

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Fences built at right Slow down longshore Thinner beaches don't Beach at St Margarets at
Groynes protect the coast as well, Cliffe, in Kent
angles to the coast drift.
trapping beach material Trap sediment. leads to greater erosion and At the top left you can see
transported by longshore Break up waves. flooding. the high chalk cliffs, made
Halting the longshore drift in from a relatively soft and
drift. Creates wider Stainless steel groynes last
one area may have effects easily eroded rock.…read more


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