cliffs. Rip-rap is designed to away beach material. The absorb the waves energy and beach builds up and protects protect the cliffs behind. the cliff by reducing power of can be effective, but does waves. look ugly, may reduce access to the beach and can be They can be effective in expensive. maintaining a beach, but need replacing regularly, look ugly and can cause problems down the coast. There is always rapid erosion after the last groyne. Sea wall: Sea walls are made out of concrete and are aimed Revetments: They are similar to absorb wave energy. to sea walls, but often built out Sometimes they are curved to of wood. Often found at the foot direct the waves energy back of cliffs they are designed at out to sea. They can be very absorb the waves energy. effective, but again are Again they need replacing expensive, ugly and reduce regularly and do not protect access. against big storms. Offshore break A structure is – created offshore and this Accept that Do nothing – reduces the power of waves so nature will win. Cost effective a beach can build up. Cheap but often unpopular locally. to build but can change local ecosystems. Sometimes an offshore break is built out waste materials and can create a coral reef. Hard engineering: Soft engineering:
cliffs. Rip-rap is designed to absorb the waves energy and protect the cliffs behind. can be effective, but does look ugly, may reduce access to the beach and can be expensive. away beach material. The beach builds up and protects the cliff by reducing power of waves. They can be effective in maintaining a beach, but need replacing regularly, look ugly and can cause problems down the coast. There is always rapid erosion after the last groyne. Sea wall: Sea walls are made out of concrete and are aimed to absorb wave energy. Sometimes they are curved to direct the waves energy back out to sea. They can be very effective, but again are expensive, ugly and reduce access. Revetments: They are similar to sea walls, but often built out of wood. Often found at the foot of cliffs they are designed at absorb the waves energy. Again they need replacing regularly and do not protect against big storms. Offshore break – A structure is created offshore and this reduces the power of waves so a beach can build up. Cheap to build but can change local ecosystems. Sometimes an offshore break is built out waste materials and can create a coral reef. Do nothing – Accept that nature will win. Cost effective but often unpopular locally. Hard engineering: Soft engineering:
ppt13_coastal_defence_intro_sheet.docx