3.4.2

Engineering Management Approaches

Test yourself

Coastal Defences - Hard Engineering

Hard engineering strategies aim to reduce the effects of flooding and erosion by building man-made structures that control the sea's flow.

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Sea walls

  • Sea walls are made out of hard concrete that deflects waves. They are often curved to dissipate the wave’s energy and refract it back towards the sea.
    • They are a good long-term solution because of the resistance of concrete, leading to less maintenance.
    • But they create a strong backwash that can undercut the wall and they are expensive to build and maintain.
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Rip-rap

  • Rip-rap is simply a pile of boulders. They are often placed in front of sea walls to dissipate the wave’s energy and support unstable rock structures.
    • They are long-lasting and relatively cheap.
    • But they provide a hazard for people accessing the beach and have gaps between the rocks allowing erosion and weathering to continue.
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Revetments

  • Revetments are angled walls placed just offshore to assist in breaking down the force of the waves to reduce their ability to erode the coastline.
    • They are a more cost-effective technique to a sea wall and reduce the rate of erosion.
    • But they often require regular maintenance and can create access problems to the beach.
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Groynes

  • Groynes are stone or wooden fences that stick out at 90o to the coast. They stop material being transported long distances by longshore drift.
    • They create wider beaches, which slows down waves and so reduces erosion and flooding. They are also relatively cheap.
    • But beaches further down the coast get narrower, which means waves are not slowed down and erosion and flooding are more likely.
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Offshore breakwaters

  • Offshore breakwaters are made up of rocks placed in a line parallel to the shore.
    • They provide calmer conditions behind the breakwater, allowing the beach to be used safely for recreational sports.
    • But they can cause wave patterns to change and are expensive to install.

Coastal Defences - Soft Engineering

Soft engineering strategies aim to reduce the effects of flooding and erosion using our understanding of the sea and working sustainably.

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Beach nourishment and reprofiling

  • Beach nourishment and reprofiling involves moving material to the upper sections of beaches from elsewhere.
  • It slows down waves by widening beaches and so reduces the risk of erosion and flooding.
    • It maintains the beach for tourist use, supporting the local economy.
    • But removing sand and shingle from the seabed threatens certain organisms (e.g. corals). It is also expensive and must be repeated.
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Dune stabilisation

  • Dune stabilisation involves the creation or restoration of sand dunes to maintain their protective position. This can be achieved through nourishment or planting vegetation.
    • This provides a natural barrier to coastal flooding and can support wildlife habitats.
    • But only a small area is protected and it is ineffective in preventing wave action during powerful storms.
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Cliff re-grading

  • Cliff re-grading and drainage involves restructuring and supporting the cliff to prevent further collapse from weathering and mass movement processes.
    • This maintains the cliff and provides a natural environment for plant and wildlife to continue to flourish.
    • But there are risks associated with altering cliff profiles which can lead to further collapsing and unintended changes to the profile.

Jump to other topics

1Tectonic Processes & Hazards

2Option 2A: Glaciated Landscapes & Change

3Option 2B: Coastal Landscapes & Change

4Globalisation

5Option 4A: Regenerating Places

6Option 4B: Diverse Places

7The Water Cycle & Water Insecurity (A2 only)

8The Carbon Cycle & Energy Security (A2 only)

9Superpowers (A2 only)

10Option 8A: Health & Human Rights (A2 only)

11Option 8B: Migration & Identity (A2 only)

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