Coastal Management

Coastal management is about resolving the conflicts between human benefits and the well-being of coastal ecosystem and protecting the coast e.g. long stretches of beaches.

Threats to the Coast

  • Erosion – The process of eroding or being eroded by wind, water, or other natural processes such as freeze thaw can mean that over a long period of time land is lost to the sea.
  • Flooding – Either because of large volumes of precipitation or because of rising sea levels (global warming) causing damage to civilisation.
  • Storm Surges A storm surge is a change in sea level that is caused by a storm. They can lead to extensive flooding and are dangerous for people living in many coastal areas.

Management of Threats

Hard-engineering Management – Hard engineering involves building some type of sea defence, usually from rocks or concrete. It aims to protect the coast from the coastal threats.

Groyne – a wall made of a sturdy timber barrier built out into the sea from a beach that interrupts water flow and limits the movement of sediment and therefor prevents erosion and long shore drift.

Advantages

  • Prevents the movement of beach material along the coast by long shore drift.
  • Allows the build up of a beach. Beaches are a natural defence against erosion and an attraction for tourists.

Disadvantages

  • Can be seen as unattractive.
  • Costly to build and maintain.

Sea Wall – a wall or embankment erected to prevent the sea encroaching on or eroding an area of land behind.

AdvantagesProtects the base of cliffs, land and buildings against erosion. Can prevent coastal flooding in some areas.

DisadvantagesExpensive to build. Curved sea walls reflect the energy of the waves back to the sea. This means that the waves remain powerful. Over time the wall may begin to erode. The cost of maintenance is high, they are also considered ugly.

Revetment – a retaining wall or facing of masonry or other material, supporting or protecting a rampart, wall.

Advantages – are strong and provide good protection by absorbing the waves energy.

Disadvantages – are that they have a relatively short life span (30-50 years) and are quite expensive, and block the sea of from the public.

Gabion – a cylindrical container made from strong wire filled with earth, stones, or other material.

Advantages

  • Absorb the energy of waves.
  • Allows the build up of a beach.

DisadvantagesCan be expensive to obtain and transport the boulders.

Rip-Rap – loose stone used to form a barrier to break the power of waves to protect the coast.

Advantages

  • Absorb the energy of waves.
  • Allows the build up of a beach.

Disadvantages – Can be expensive to obtain and transport the boulders.

Overall Disadvantages of Hard-engineering

  • Expense – Most Structures are expensive to build, maintain and repair.
  • Rising Sea Levels – These structures will be ineffective after sea levels rise.
  • Aesthetics – Structures can spoil the natural Beauty of coastlines.

Soft-engineering Management

Soft-engineering is just things such as using diggers to deposited sand, offshore underwater bars, changing the angle of a cliff and using fencing, hedging and replanting vegetation.

Soft engineering options are often less expensive than hard engineering options. They are usually more long-term and sustainable, with less impact on the environment.There are two main types of soft engineering:

Beach Management

  • This replaces beach or cliff material that has been removed by erosion or long shore drift.
  • The main advantage is that beaches are a natural defence against erosion and coastal flooding. Beaches also attract tourists and have ornamental value.
  • It is a relatively inexpensive option but requires constant maintenance to replace the beach material as it is washed away.

Overall Coast Management

  • Do Nothing – this means that along these stretches there are few if any risks. The coast is safe and secure.
  • Hold the Line – this means the use of hard-engineering to prevent damage to the coastline because of the useful land behind.
  • Managed Retreat – this means the strategic giving away of the coastline.
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