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Coastal Management IGCSE Geography
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By Laurence Kobrock
Coastal Management / Protection
What is Coastal Management?
Coastal management is defence against flooding and erosion and techniques that allow erosion to claim land.
Why do we do it?
In the case of humans, we use the coastline for agriculture, for fishing, for industry and power generation, for transport routes and for land upon which to live. However, a lot of these land uses are incompatible with the fact that the coastline is constantly changing. Erosion processes remove land from some parts of the coastline, whereas deposition processes create new land in other places. In addition, the fact that the sea level is rising locally and globally could add to these erosion and deposition problems whilst also removing land from use at the coastline.
What are Hard / Soft measures?
Hard
• Hard engineering involves the building of entirely artificial structures using various materials such as rock, concrete and steel to reduce or stop the impact of coastal processes
• Ex:– Groynes– Sea Walls
Soft
• Soft engineering options are often less expensive than hard engineering options. They are usually more long-term and sustainable, with less impact on the environment
• Ex: – Beach Nourishment– Due Regeneration
Recurved Sea Wall
• Massive, made of rocks or concrete, used to absorb waves. Some types can act as Baffles
Advantages
• Very effective• Reasonably long
lifespan• Traditional solution• Can prevent coastal
flooding in some areas
Disadvantages
• Very costly• Visual pollution• High maintenance
cost
Groynes
• Rock or wooden types, hold beach material threatened by LSD erosion
Advantages
• Low capital costs• Repaired pretty easily
Disadvantages
• Need regular maintenance
• Cause scour downdrift• Visual pollution
Rip Rap (rock armour)
• Very large rocks in front of sea walls to absorb waves
Advantages
• Very effective• Prevents large-scale
undermining
Disadvantages
• Expensive• May move in severe
weather
Off shore reefs
• Reduces power of waves offshore
Advantages
• Can be built of waste materials
• No visual pollution
Disadvantages
• Possible ecological impacts
• May not work at large scale
Toe armouring
Advantages
• Low maintenance costs• 30-50 years effectiveness
Disadvantages
• High construction costs• Disruption to ecology
Revetments
• Made of concrete or wood.
• Reflects waves rather than resist them
Advantages
• Cheaper than sea walls• Traditional solution to
protect valuable resources, densely populated areas an high-risk property
Disadvantages
• Costly• Do not cope well with
very strong waves• Visual pollution
Gabions
• Wire cages holding smaller rocks
• Bank/cliff stabilisation
Advantages
• Cheaper than revetments• The rocks absorb a
moderate amount of wave energy
Disadvantages
• Relative small scale solution
• Visual pollution
Cliff Stabilisation
• The drainage of excess rainwater by terracing, planting and wiring to keep the cliff in place
Advantages
• Cost effective
Disadvantages
• A moderate amount of visual pollution
• Effects the ecology of the cliff
Cliff drainage
• Removal of water in order to prevent landslides and slumping
Advantages
• Cost effective
Disadvantages
• Drained cliffs can dry out and lea to collapse
• Has effects on the ecology
• Visual pollution
Beach nourishment
• Sand pumped or transported to replace losses by LSD
Advantages
• Looks like a ‘natural looking’ process
Disadvantages
• Expensive• Will erode soon• Ecological effects
Natural (do nothing)
• Land no longer worth protecting. Lets the sea erode the land with no intervention
Advantages
• Saves expenditures on defence
• No impact on nature and ecology
Disadvantages
• May allow problems to get worse
• Loss of land