Type of Scheme |
Description |
Cost |
Advantages |
Disadvantages |
Sea Wall |
* Concrete or rock barrier placed at the foot of cliffs or at the top of a beach. * Has a curved face to reflect the waves back. * Is usually 3-5m high. |
Up to £6million per km (south sea zones) |
* Effective at stopping the sea. * Often has a walkway or promenade for people to walk along. |
* Can be obtrusive and unnatural to look at. * Very expensive and has high maintenance costs. * Creates a strong backwash which erodes under the wall. |
Groynes |
* Timber or rock structures built out to the sea from the coast. * They trap sediment being moved by longshore drift - enlarging the beach. * The longer beach acts as a buffer to the incoming waves, reducing wave attack on the coast. |
£10,000 each (at 200m intervals) |
* Result in a bigger beach, which can enhance the tourist potential. * Provide useful structures for people interesting in fishing. * Not too expensive. |
* In interrupting longshore drift, they starve beaches downdrift, often leading to increased rates of erosion elsewhere. The problem isn't solved, but shifted. * Groynes are unnatural and rock groynes in particular can be unattractive. |
Rock Armour |
* Piles of large boulders dumped at the foot of a cliff. * The rocks force waves to break, absorbing their energy and protecting the cliffs * The rocks are usually brought in by barge to the coast. |
Approximately £1,000 - £4,000 per metre. |
* Relatively cheap and easy to maintain. * Can provide interest to the coast, often used for fishing. |
* Rocks are usually from other parts of the coastline or even from abroad. * They do not fit in with the local geology. * Can be very obtrusive. |
Type of Scheme |
Description |
Cost |
Advantages |
Disadvantages |
Beach Nourishment |
* Addition of sand or shingle to an existing beach to make it higher or broader. * The sediment is usually obtained locally so that it blends with the existing beach material. * Usually brought onshore by barge. |
Approximately £3,000 per metre |
* Relatively cheap and easy to maintain. * Blends in with existing beach. * Increases tourist potential by creating a bigger beach. |
* Needs constant maintenance unless structures are built to retain the beach. |
Dune Regeneration |
* Sand dunes are effective buffers to the sea, yet they are easily damaged and destroyed, especially by trampling. * Marram grass can be planted to stabilise the dunes and help them to develop. * Areas can be fenced to keep people off newly planted dunes. |
Approximately £2,000 per 100 metres. |
* Maintains a natural environment that is popular with people and wildlife. * Relatively cheap. |
* Time consuming to plant the marram grass and fence off areas. * People do not always respond well to being prohibited from accessing certain areas. * Can be damaged by storms. |
Marsh Creation (Managed Retreat) |
* Involves allowing low-lying coastal areas to be flooded by the sea to become salt marshes. * This is an example of managed retreat. * Salt marshes are effective barriers to the sea. |
Depends on the value of the land. Arable land costs somewhere in the region of £5,000 to £10,000 per hectare. |
* A cheaper option than maintaining expensive sea defences that might be protecting relatively low-value land. * Creates a much-needed habitat for wildlife. |
* Land will be lost as it is flooded by seawater. * Farmers or landowners will need to be compensated. |