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Managing coastlines EQ4 - Coggle Diagram
Managing coastlines EQ4
Consequnces of coastal recession
Economic and social losses
damage to houses and businesses mean that people are forced to relocate whilst repairs are done and financial support is needed to support this
many people in less developed countries have limited financial assets and are reliant on international aid
in more developed countries like UK, many people can't get enough insurance to cover potential damages, and many houses lose value as the rate of coastal recession increases
South-west Uk railway line:
2014, heavy storms damaged the railway line that provided a key connection for commuters travelling between Devon, Cornwall and other parts of UK
estimated the two-month closure of the railway line for repairs cost the UK economy £1.2 billion through disruption to the tourist and fishing industries in the local area
Austarlian coastal flooding:
rising sea levels in Australia are increasing the risk of coastal flooding
a $216 billion worth of key infrastructure, e.g. road and rail networks, residential housing, commercial properties and emergency service stations, are at risk in the future if sea levels continue to rise
The Maldives:
made up of over 1,000 islands, one of lowest lying countries in the world
serious risk of being completely submerged due to coastal flooding
islands rely on tourism as a key contributor to the local economy, but increased coastal flooding events threaten the physical features that cause many people to leave
coastal flooding also threatens housing + freshwater sources, which has forced many locals to migrate away from the annual flooding
Engineering Management approaches
Hard engineering
aim to reduce the effects of flooding and erosion by building man-made structures that control the sea's flow
Sea walls:
made out of hard concrete that deflects waves, often curved to dissipate wave's energy and refract it back towards the sea
good long term solution because resistance of concrete leads to less maintenance
create a strong backwash that can undercut the wall and are expensive to build and maintain
Rip-rap:
pile of boulders, often placed in front of sea walls to dissipate the wave's energy and support unstable rock structures
long lasting and relatively cheap
provide a hazard for people accessing the beach and have gaps between the rocks allowing erosion and weathering to continue
Reventments:
angled walls placed offshore to assist in breaking down the force of the waves to reduce their ability to erode the coastline
more cost-effective technique to a sea wall and reduce the rate of erosion
often require regular maintenance and can create access problems to the beach
Groynes:
stone or wooden fences that stick out at 90 degrees to the coast, they stop material from being transported long distances by longshore drift
create wider beaches, which slows down erosion and flooding, relativley cheap
beaches further down the coast get narrower, means waves are not slowed down and erosion and flooding are more likely
Offshore breakwaters:
made up of rocks placed in a line parallel to the shore
provide calmer conditions behind the breakwater, allowing the beach to be used safely for recreational sports
they can cause wave patterns to change and are expensive to install
Soft engineering
aim to reduce the effects of flooding and erosion
Beach nourishment and reprofiling:
involves moving material to the upper sections of beaches from elsewhere
slows down waves by widening beaches and so reduces the risk of erosion and flooding
maintains the beach for tourist use, supporting the local economy
removing sand and shingle from the seabed threatens certain organisms. it is also expensive and must be repeated
Dune stabilisation:
involves the creation or restoration of sand dunes to maintain their protective position, can be achieved through nourishment or planting vegetation
provides a natural barrier to coastal flooding and can support wildlife habitats
only a small area is protected and it is ineffective in preventing wave action during powerful storms
Cliff re-grading:
involves restructuring and supporting the cliff to prevent further collapse from weathering and mass movement processes
maintains the cliff and provides a natural environment for plant and wildlife to continue to flourish
risks associated with altering cliff profiles which can lead to further collapsing and unintended changes to profile