COASTAL PROTECTION
Coastal protection techniques can be divided into two different types - hard engineering techniques and soft engineering techniques.
HARD ENGINEERING TECHNIQUES
Hard engineering techniques are usually physical barriers that are built to try and deflect the power of the waves. They are expensive to implement and often need continued economical investment to maintain them. They are usually extremely visible and may be deemed an eye-sore. These techniques are often used to protect coastal towns or areas with a higher land value.
GROYNES
Groynes are often made of wood and extend perpendicular from the beach out into the tidal zone. They trap sediment against them to prevent it being carried further down the coastline. This sediment then helps reduce the impact the waves have against the coastline, thus reducing erosion. As groynes stop the sediment moving down shore, it can often result in beach thinning further down the coastline as their sediment supply has been cut off.
GROYNES
Groynes are often made of wood and extend perpendicular from the beach out into the tidal zone. They trap sediment against them to prevent it being carried further down the coastline. This sediment then helps reduce the impact the waves have against the coastline, thus reducing erosion. As groynes stop the sediment moving down shore, it can often result in beach thinning further down the coastline as their sediment supply has been cut off.
SEA WALLS
A sea wall is a physical (often concrete) wall that is built where the waves hit the base of a cliff. The wall absorbs the energy of the waves when hit and reduce the erosion. They are often big, extremely expensive and need constant maintenance. They are usually deemed as an 'ugly' defence and are not always popular with the local community. Due to the high cost, sea walls are mainly only used to protect towns from erosion.
A sea wall is a physical (often concrete) wall that is built where the waves hit the base of a cliff. The wall absorbs the energy of the waves when hit and reduce the erosion. They are often big, extremely expensive and need constant maintenance. They are usually deemed as an 'ugly' defence and are not always popular with the local community. Due to the high cost, sea walls are mainly only used to protect towns from erosion.
GABIONS
Gabions are cages that contain large pieces of rock and are placed at the base of eroding cliffs. They are cheaper that sea walls but do not last as long and are often deemed as unsightly.
Gabions are cages that contain large pieces of rock and are placed at the base of eroding cliffs. They are cheaper that sea walls but do not last as long and are often deemed as unsightly.
REVETMENTS
Revetments are not dissimilar to sea walls but are smaller and not as expensive. They are slanted barriers (made of wood or concrete) that protect the base of the cliff. They absorb the energy from the wave to reduce the cliff erosion.
Revetments are not dissimilar to sea walls but are smaller and not as expensive. They are slanted barriers (made of wood or concrete) that protect the base of the cliff. They absorb the energy from the wave to reduce the cliff erosion.
OFF SHORE REEFS (or BREAKWATERS)
Off Shore Reefs are man-made barriers built out at sea that reduce a waves energy before it reaches the beach. These reefs are expensive to build and hard to maintain as they are difficult to reach once built. They can also change the wave direction and whilst they reduce the wave energy, they do not physically protect the cliff, so it will still be eroded.
Off Shore Reefs are man-made barriers built out at sea that reduce a waves energy before it reaches the beach. These reefs are expensive to build and hard to maintain as they are difficult to reach once built. They can also change the wave direction and whilst they reduce the wave energy, they do not physically protect the cliff, so it will still be eroded.
SOFT ENGINEERING TECHNIQUES
Soft engineering techniques are often more natural techniques employed to help reduce the impact that waves have on a coast without putting up physical, man-made barriers. These techniques are often less expensive and, once established, may not require continued investment. They are often implemented in areas that need protecting but don't have enough value to warrant using hard engineering techniques.
SAND DUNES
Sand dunes are a natural defence against erosion. They act as a physical barrier between the waves and cliffs and provide a natural habitat for plants and animals. As they are natural they are inexpensive. They can, however, be man-made to help protect a coastline. If they are man-made they will require maintenance but this would be deemed more economical for an area than having to use a hard engineering method.
SAND DUNES
Sand dunes are a natural defence against erosion. They act as a physical barrier between the waves and cliffs and provide a natural habitat for plants and animals. As they are natural they are inexpensive. They can, however, be man-made to help protect a coastline. If they are man-made they will require maintenance but this would be deemed more economical for an area than having to use a hard engineering method.
MANAGED RETREAT
Managed retreat is often used as a last resort or in an area that has a low land value (such as farm land). The coast is left without any defences and is allowed to be eroded. Whilst this area is being eroded, the land behind the designated area is protected. This technique has its limitations as, once the designated area is eroded, the coastline will retreat and the higher value land behind will become vulnerable.
Managed retreat is often used as a last resort or in an area that has a low land value (such as farm land). The coast is left without any defences and is allowed to be eroded. Whilst this area is being eroded, the land behind the designated area is protected. This technique has its limitations as, once the designated area is eroded, the coastline will retreat and the higher value land behind will become vulnerable.
BEACH NOURISHMENT
Beach nourishment involves moving sediment from an area of deposition to an area of erosion along a coastline. The sediment is used to widen and build up the beach, meaning the beach absorbs more of the waves energy, thus reducing erosion at the cliff base. Whilst this is a man-made technique it is relatively inexpensive as the sediment is already available and it uses only natural resources. This techniques does require constant maintenance as the beach will be eroded and will need to be re-built again.
Beach nourishment involves moving sediment from an area of deposition to an area of erosion along a coastline. The sediment is used to widen and build up the beach, meaning the beach absorbs more of the waves energy, thus reducing erosion at the cliff base. Whilst this is a man-made technique it is relatively inexpensive as the sediment is already available and it uses only natural resources. This techniques does require constant maintenance as the beach will be eroded and will need to be re-built again.