Coastal Defences

By Josh L 11JJ

Groyne's

Groyne's are one of the most effective methods of coastal defences. Groyne’s are large structures which extend into the sea to try and stop long shore drift. Groyne’s are usually made of either wood, concrete or piles of large rocks. Groyne’s are fairly cost effective as they protect the coastline effectively however, they look ugly and unnatural.

Gabion’s

Gabions are mesh cages which contain rocks and small stones (rip-rap) which help to try and break up waves. Gabions are fairly cheap and are very effective. They don’t scar the landscape too much as moss and grass can grow on top of them. They are more effective then just rip-rap itself as they can be arranged into shapes and won’t get washed away easily.

Sea Wall’s

Sea walls are another form of sea defence which are usually made of concrete or rock and are put along the coastline to protect an area from flooding or coastal erosion. The sea walls are designed to reflect the waves energy back out to sea. Sea walls are quite unattractive but effective when placed in the right area of a coastline.

Revetments

Revetments are wooden barriers usually placed slanted or upright which protect a settlement from the sea. Waves break against the revetments and the power is put back into the sea. They are fairly cheap (£1000 per msq) and also effective although they aren’t nice to look at.

Rock Armour

Rock armour is basically where there are piles of rocks placed at the base of cliff’s, dunes or coastlines. The rocks absorb the power of the waves and are fairly effective except in storms. It is an expensive method (£3000 per msq) but doesn’t scar the landscape that much. Rock armour does need repairing every so often as the rocks wear away after time.

Beach Nourishment

Beach nourishment is when extra sand is added to beach to make the beach wider and to make it spread into the sea more. It is used instead of other sea defences as it is effective and doesn’t visually effect the beach in a negative way. Beach Nourishment is an expensive process ranging from £5000-200,000.

Thanks to:

Photobucket (images)

Wikipedia (information and images)

Google (images)