Coastal Management Strategies

What is Coastal erosion?

The vanishing of coastal areas due to natural factors like wind or waves is called coastal erosion. Look at the diagram below to see how coastal erosion occurs.

Coastal erosion

Coastal Defence

Hard engineering

Hard engineering strategies are human made structures that are used to defend the coastline. Although quite effective strategies, these are on the expensive side of the budget and needs timely maintenance. Artificial structures are made to protect the sea cliffs.

Groynes

These are wooden fences that prevent longshore drift. Sands and pebbles collect between these fences and build a beach.

Groynes

Positive impact

  • Increase in tourism due to development of beach.
  • Longshore drift cannot take away the sand and pebbles available on the beach.

Negative impact

  • These do not give an aesthetic look to the beach.
  • They do not allow the sediments to spread further on the beach leading to erosion on a different place.

Sea walls

Curved concrete walls built at the back of the beach send the wave energy back to the sea. These made of concrete at the base of the cliff to prevent erosion.

Sea walls

Positive impacts

  • Effectively protect the foot of the cliff.
  • Promenade can be made on these so that public can walk along the seafront.

Negatives

  • These are very expensive.
  • Powerful waves can still break them and erode them away, so continuous maintenance are required.

Rock Armour

Large boulders are placed at the base of cliffs. Wave energy is absorbed that helps in reduction of erosion and preventing cliff collapse.

Rock Armour

Advantages

  • These are also used for fishing.
  • It is a cheaper option than a sea wall and maintenance is also easy.

Disadvantages

  • Transportation of big rocks is difficult and expensive.
  • Rocks which do not belong to local geological structure looks a bit odd as it does not match the structures in the surrounding area.

Gabions

Boulders and rubbles are wired together into large blocks to stop them from moving. The blocks absorb the wave energy.

Gabions

Advantages

  • These are cheap and absorb wave energy effectively.

Disadvantages

  • These are relatively less sturdy than other options.
  • These also look odd as the mesh structures give an unnatural look to the surroundings.

Cliff stabilization

Cliffs are weak when steep and saturated. To prevent the collapse of the cliff, it can be graded and drains are also installed in it.

Cliff stabilization

Soft engineering

It is a sustainable and natural approach for managing coastal areas. It does not involve artificial structures but uses natural resources available to maintain the coastal areas.

Beach nourishment

Material dredged from the sea bed is used to build up the beach. Sand is pumped into the existing beach to make it more firm against the waves.

Beach nourishment

Advantages

  • The new sand blends with the previous land and looks natural.
  • It improves the aesthetic beauty of the place and attracts more tourism.

Disadvantages

  • The sand needs to be constantly replaced with new and better grain of sand.
  • The sand has to be transported from one place to another.

Reprofiling

This is usually done when a storm hits a beach and unevenly erode the area. With the help of bulldozers, sand is spread evenly all around the area. The sand is redistributed from the lower part of the beach to the upper part of the beach.

Reprofiling

Advantages

  • It only needs a bulldozer to redistribute the sediments and thus is a simple and cheap technique to maintain coastal areas.
  • It decreases the energy of waves to some extent.

Disadvantages

  • It is not very effective in case the high energy waves hit the beach.
  • These need to be repeated continuously.

Dune nourishment

Grass is planted on dunes which help in stabilizing these dunes by trapping the sand between them.
Similarly, afforestation is also done to hold the sand in the place.

Advantages

  • A cheap alternative.
  • Makes the coastline area beautiful.

Disadvantages

  • These are relatively easily damaged by the storm waves.
  • Areas have to be kept away from the public interference which makes it unsuitable for tourism.

Managed Retreat

It allows the exposure of land near to coastal area to flooding so that the waves pressure is distributed and it does not erode a specific area.

Advantages

  • This is the cheapest option as compared to other coastal protection strategies.
  • The formation of salt marshes allows wildlife to make this place their habitat and also work as natural defence against floods and erosion.

Disadvantages

  • A large area is covered by the sea which can’t be used for any other purpose.
  • The owners of the land need to be compensated for the cost of land occupied for flooding.