Erosion is a natural process which shapes cliffs. Over time, erosion can cause cliff collapse - therefore the coastline needs to be managed. Hard engineering involves building artificial structures which try to control natural processes.

Sea walls

Image of a sea wall in Essex A sea wall

Concrete walls that are placed at the foot of a cliff to prevent erosion. They are curved to reflect the energy back into the sea.


  • Effective at protecting the base of the cliff.
  • Sea walls usually have promenades so people can walk along them.


  • Waves are still powerful and can break down and erode the sea wall.
  • Expensive - approximately £2,000 per metre.

Rock armour/rip rap

Rock armour Rock armour on a beach

Large boulders placed at the foot of a cliff. They break the waves and absorb their energy.


  • Cheaper than a sea wall and easy to maintain.
  • Can be used for fishing.


  • They look different to the local geology, as the rock has been imported from other areas.
  • The rocks are expensive to transport.


Gabions Gabions

Rocks are held in mesh cages and placed in areas affected by erosion.


  • Cheap - approximately £100 per metre.
  • Absorb wave energy.


  • Not very strong.
  • Look unnatural.


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