Coastal defence Flashcards
Soft engineering
Works with nature and makes use of natural products in order to protect the coastline (e.g. Managed retreat or beach nourishment)
Hard engineering
Works against nature and involves the construction of expensive man made defences (e.g. groynes and sea walls)
Planting vegetation
Soft engineering method which offers protection as the roots build up a beach by holding all the sand together. This beach then absorbs the power of the waves.
Beach nourishment
Placing sand onto an existing beach to increase its height and width. This beach can then absorb the power of the waves and reduce coastal erosion.
Gabions
Hard engineering approach where cages are filled with small rocks and toed together. These cages absorb the power of the breaking wave and so protect the coastline.
Manages retreat
Soft engineering approach. Areas of the coast are allowed to be flooded and eroded away. This occurs up to a managed point where some defence may be installed. This method is only used where land values are low.
The Holderness
Heavily protected coastline because of the rapid rate of erosion (2m+ per year) caused by the cliffs being weak and made of boulder clay.
Recurve sea wall
The wave’s energy is bounced back out to sea because of the curved shape. It also prevents flooding of the coastal area.
Groynes
These are placed at right angles to the beach and are designed to stop the movement of sediment because of LSD. This builds up the beach which is then a natural defence.
Cliff drains
Soft engineering approach which allows water to flow out of the cliff face and therefore keep it more stable.
Rock armour
Large chunks of rock placed at the bottom of the cliff to absorb the power of the waves and prevent or reduce erosion.