What is Coastal Management? This refers to sea defence or coastal protection All three of which means protection of the beach against flooding and erosion
Hard Engineering These are methods that aim to stop the coastal processes from occurring It involves the use of man made structures to defend against the erosive power of waves Some structures used are gabions, groynes, re-curved sea walls, revetments and rip raps
Soft Engineering These are methods that try to work with nature to protect the coast These focus on planning, management and changing individual attitudes towards coastal protection Beaches or naturally formed materials are used to control or re-direct erosion processes Some coastal features used are sand dunes and salt marshes. Beach replenishment is also a form of soft engineering
They help to protect the coast and harbour by reducing the force of high energy waves before they reach the waves
They create a zone of calm water behind them
However, materials deposited in the zones behind them are protected but in the zones located away from the breakwater they are not, and will be eroded away
These are large steel mesh cages filled with rocks
They are built into cliff faces to protect the cliff from the force of the waves
Though they are less costly than sea walls, the life span is shorter as they will eventually begin to rust
Often described as fences built at right angles to the coastline
The aim is to stop the movement of material along the beach due to longshore drift
They are effective at reducing erosion in the area they are constructed in by causing significant build up of beach material.
However, they deprive areas further down the coastline of material as they stop longshore drift
Re-Curved Sea Wall
A concrete wall curved on the underside to reflect the energy of waves
However, they are very effective as the reflect wave energy rather than absorb it.
Huge boulders (10 tonnes min.) stacked on beaches for use as a sea wall
Energy of the wave is dissipated effectively as water is let through the spaces between the boulders
These boulders must be big enough to withstand being eroded themselves
Wooden structures that break the force of waves
Beach material builds up behind them
Need replacing more frequently than other structures
Beach Replenishment This process involves the transportation of sand from elsewhere to be distributed along the beach Environmentally, this is the preferred method as it keeps the beauty of the landscape of the beach It is very costly and time consuming as regular replenishments are required
Relocation of Property
Coastal planners are trying to protect man-made structures by relocating them and let nature reclaim the beach slowly.
No building of new structures is allowed in coastal areas vulnerable to coastal erosion.
This approachis likely to be opposed by people who want to invest in the coastal areas.
Planting of Mangroves Mangroves can help to trap sediments and reduce coastal erosion. However some areas with violent destructive waves may not support mangroves. The depth of the coast may also become shallower, affecting coastal transportation and port activities.
Stabilising Dunes Coastal dunes can be found along the shore where lots of sand and strong winds exist. The winds carry and deposit the land on the coast further inland, forming coastal dunes gradually which help defend the coast from the sea. However they are very fragile and thus access points to the beach are controlled and designated. Shrubs and trees are planted to stabilise the dunes to anchor the sand.
Growth of Coral Reefs They can weaken wave energy. Artificial reefs are created along the coast to help enhance fishing opportunities, serve as undersea barriers and replace damaged coral reefs.