Protecting the Coastline

There are two approaches to protecting the coastline and the buildings that stand upon it, hard engineering and soft engineering.

Hard engineering: A technique involving the construction of significant man-made structures to manage the coastline. e.g. sea walls and rock armour.

Soft engineering: A technique involving the construction of more environmentally friendly, less damaging and arguably more sustainable management solution. e.g. beach nourishment or managed retreat

Hard engineering approaches:

• Groynes

Timber or rock constructions built out to sea from the coast that trap sediment moved by longshore drift and broaden the beach. The wider beach acts as a buffer to incoming waves which helps to reduce wave attack on the coast. It costs around €6000 per metre.

• Sea wall

A concrete or rock barrier built at the bottom of cliffs or at the top of a beach, which is used to reflect and refract waves away from the shoreline. It has a curved face to help with reflecting the waves back into the sea and is generally 3-5m high. It costs around €11 billion to build.

• Rock armour

Piles of large boulders dumped at the bottom of a cliff which forces waves to break, absorbing their energy and protecting the cliff. The boulders are transported to their location by barges. It costs around €1200-€4800 per metre, depending on the location.

• Gabions

Baskets or cages filled with earth or rocks and used especially in building supports to reduce erosion. They offer resistance to erosion and a safeguard to properties in danger of slipping into the sea. They cost €13.06 per metre.

Soft engineering approaches:

• Dune regeneration

Sand dunes are good buffers to the sea, but are easily damaged, especially by walkers and human activity. Marram grass can be planted to help stabilise the dunes and help them to develop. Areas can be fenced off to keep people off newly planted dunes. They cost €2375.26 per 100m.

• Beach nourishment

Adding sand or shingle to a beach to make it higher or broader. The sediment used is often from local areas, so as to be able to blend in with its surroundings. It costs around €3600 per metre squared.

• Managed retreat/Marsh creation

This involves allowing the low-lying coastal areas to be flooded by the sea to become salt marshes. Salt marshes are effective barriers to the sea. The cost depends on the value of the land, but generally anywhere between €5938.15 and €11876.30 per hectare.