As things like coastal tourism have become more frequent, humans have found it increasingly necessary to attempt to control the effects of the sea. The main reasons for coastal management are:
- to protect the coast from the erosive effects of the sea.
- to increase the amount of sand on the beach.
Many strategies have been tried around the world, and these can be divided into two main groups, hard and soft engineering. Hard engineering methods aim to stop the coastal processes from occurring. Soft engineering methods try to work with nature to protect the coast. Examples of these two strategies are:
- Often built in front of seaside resorts.
- Very expensive.
- They aim to completely block the waves and their effects.
- Life span of approximately 75 years.
- Can cause the erosion of the beach in front of them.
- Socially reassuring for local residents.
- Wooden “fences” built at right angles to the coastline.
- They aim to stop the movement of material along the beach due to long shore drift.
- Their primary intention is to build up the amount of sand on the beach.
- They have a life span of approximately 25 years.
- Large steel mesh cages filled with large rocks.
- Aligned at right angles to the coastline.
- They aim to do a similar job to wooden groynes.
- Expected life span of 20 – 25 years, as the steel will rust.
Rip Rap / Rock Armour:
- Large boulders, of 10 tonnes or more, are used as a sea wall.
- The gaps between the rocks allow water through, which means that the energy of the waves is dissipated very effectively.
- It is important that the boulders are big enough to withstand being eroded themselves and therefore becoming part of the coastal system.
- Sand is either brought in from elsewhere, or transported back along a beach, usually once a year.
- This is done using trucks, and is therefore very costly and time consuming.
- Over the next 12 months the material is washed along the coast by long shore drift, before being replaced again. The final method of coastal management is of course to do nothing and allow the sea attack the coastline naturally.
- Most of the solutions detailed are very costly, and in many places questions are being asked as to whether they are actually worth the money.
Problems of disrupting the natural coastal system:
- Whenever you tamper with nature there are going to be knock on effects, which could, in time, become worse than the original problem.
- Coastal defence strategies are often very localised, and can cause problems further down the coast. One such example could be seen where groynes are used to trap sediment. Further down the coast there could be a reduction in the amount of material available to protect the coast there. This in turn would mean an increased amount of coastal erosion.