Coastal protection management
Differentiate between hard engineering methods and soft engineering methods of coastal management.
Evaluate the success of coastal protection measures.
Hard engineering approach
The construction of physical structures to defend against erosive power of waves.
Soft engineering approach
Focuses on planning and management so that both coastal areas and properties will not be damaged by erosin
Aims at changing individual behavior or attitudes towards coastal protection by encouraging minimal human interference
Seawalls: are built along the coast to absorb the energy of waves before they can cause erosion
However they cannot prevent the backwash of the refracted waves from washing away beach materials beneath the wall
Breakwaters: can be built with one end attached to the coast or away from the coast
Materials deposited behind the breakwater are protected but the zone located away from the breakwater is not
Relocation of properties: no building of properties are allowed in coastal areas vulnerable to coastal erosion the east coast of England has a green line policy that discourage building located beyond it
With the danger of increasing sea levels due to global warming relocation is important to future coastal management
Planting of mangroves: mangroves with their prop roots help trap sediments and reduce coastal erosion as mangrove communities grow seawards they extend the coastal land seawards
Stabilising dunes: access points to the beach should be controlled and designated so as not to be disturbed by human traffic
Shrubs and trees can be planted to stabilize then roots and trees reach downwards to tap groundwater and anchor the sand in the process
Growth of coral reefs: artificial reefs can be created by placing environmentally friendly and long lived materials like steel or concrete on the sea floor once the material is put in place living organisms start to grown on it man made reefs are as productive as natural reefs in enhancing fishing opportunities and serve as undersea barriers to reduce impact of wave energy.
Gryones: are built at right angles to the shore to prevent longshore drift.
gabions: they are wired cages filled with crush rocks are pilled up along the shore to prevent or reduce coastal erosion by weakening wave energy
beach nourishment: the coastal constant replenishment of large quantitites of sand to the beach system the beach is extended seawards which leads to the improvement of beach quality and storm protection
Differences between soft and hard engineering:
soft engineering is the use of ecological principles and practices to reduce erosion and achieve the stabilization and safety of shorelines and the area surrounding rivers, while enhancing habitat, improving aesthetics, and saving money. hard engineering is generally defined as controlled disruption of natural processes by using man-made structures.
HARD ENGINEERING
- SEAWALLS: absorb shock of waves
- BREAKWAVES: protect coast from high energy waves
- GRYONES: encurage build up of beach
- GABIONS: weaken wave erosion
- BEACH NOURISHMENT: improves beach quality
- RELOCATION OF PROPERTIES: allow nature to take course
- PLANTING OF MANGROVES: helps trap sediments to form islands
- STABILIZING DUNES: vegetation growth on dunes sand anchor
- GROWTH OF CORAL REEFS: encourages growth of organisms