Coastal Managment Flashcards
Why manage the coast?
23% total land area lives within 10 km of the coast
16.9 million people live within the coastal zone
Land around it needs protecting so therefore we need to protect the coast:
33% pasture land
25% arable land
30% covered by buildings, roads, recreation
40% of uks manufacturing industry lies close to the coast (could have big economic loss if destroyed)
What are the 3 reasons for coastal management?
- coastal erosion
- coastal flooding
- failure of former defences
What is “hold the line” as a possible management strategy?
Maintain current defences or build new ones to ensure coastline stays where it is
What is “advance the line” as a possible management strategy?
Build new defences seaward of existing line
What is “retreat the line” as a possible management strategy?
Allow the coastline to retreat due to flooding and erosion but closely manage the rate and location of this retreat
What is “do nothing” as a possible management strategy?
Low value areas left to natural coastal processes as not deemed viable to spend on deferences
What general factors may dictate the approach taken?
Who is impacted?
Is there ecological importance?
Likelihood of succces?
What are the alternatives?
Cost of defence?
Any alternatives?
What are social factors that may dictate approach taken?
- if there is anything there to protect e.g. peoples houses/how many live there
- is there many facilities around (hospitals, schools)
- areas of importance?
What are economic factors which may dictate approch taken?
- if there is many tourists coming into the coastal area, boosting the economy
- if big city/area which generates money they could advance the line
What are political factors which may dictate the approach taken?
- if there is a war/unrest then it doesn’t need to look nice, as it may get destroyed anyway
- if it is of political/historic importance they should advance the line
What are environmental factors which may dictate the approch taken?
- if there is unique wildlife/plant species at risk of being destroyed, or any endangered species
- the amount of plants/trees
What is a cost-benefit analysis?
They are carried out before a coastal management project is given the go ahead.
What are the 2 types of cost-benefit analysis?
Tangible
Intangible
What is a tangible cost-benefit analysis?
Where costs and benefits are known and can be given a monetary value
What is an intangible cost benefit analysis?
Where costs may be difficult to access but are important (e.g. visual impact)
What are some examples of tangible factors?
-The amount of houses/infrastructure protected
-the actual cost ($)
- value of land
- value of businesses
What are some intangible factors?
The wildlife affected
How many rabbits/birds?
Is it going to look more attractive/less?
Cultural factors (loss of graveyards)
What is soft engineering?
Works with nature and natural system to protect the coast
What is hard engineering?
Making a physical change to the coast line using man made materials and/or structures
What is a sea wall? (H)
A structure made of concrete. It is built parallel to the shore at the transition between the mainland and the coast, to protect the inland areas against wave action/erosion
What are some advantages of sea walls?
- sense of security/safety
- promonards on top, popular with tourists
- long life span
- don’t impend the movement of material on the coast
What are some disadvantes of sea walls?
- can effect access to the beach
- coastal flooding can occur if waves break over the sea wall
- expensive to construct/maintain
- reflected waves scour the beach and can cause foundations to be undermined
How much do sea walls cost?
Devon, dawlish = 30 million
What are gabions?(H)
Coastal defences that consist of rocks and boulders encased in a wired mesh
They absorb energy from waves
What are some advantages of gabions?
Doesn’t impend access to beach
Cheap to build and maintain/last ages
Doesn’t stop sediment movement
What are some disadvantages of gabions?
Can be very dangerous if damaged
Restricted to sandy beaches
Can be dangerous to animals/birds
Ugly
How much do gabions cost?
Approx 110 a metre
What are barrages? (H)
A type of low-head division dam which consists of a number of large gates that can be opened or closed to control the amount of water passing through it
What are some advantages of barrages?
- flood control
- can be used for electricity production without big environmental impact
- water diversion
What are some disadvantages of barrages?
- ecological harm
- disrupts sediment flow
- expensive construction
- impact on aquatic life
- limited suitable locations
- expensive
How much do barrages cost?
Severn barrage, estimate cost of 20.9 billion
What is beach nourishment (S)?
Beaches are made higher and wider by importing sand and shingle to an area affected by SLD to increase its height and width to provide protection
What are some advantages of beach nourishment?
- cheap
- retains a natural appearance
- defends from erosion
- increases tourism
What are some disadvantages of beach nourishment?
- increase erosion in other areas
- affects the marine ecosystem
- large storms increase costs
How much does beach nourishment cost?
Around 20 pounds per meter cubed
What is managed retreat (S)?
The planned movement of moving beach from one place, backwards, letting it move inland. Breech current defences, allowing water to break through
What are some advantages of managed retreat?
- cheap
- environmental benefits (habitats)
- sight of major tourism
What are some disadvantages of managed retreat?
- agriculture land gets ruined, taken over by sea water (turned into salt marshes)
- loss of food productivity
How much does managed retreat cost?
“Donna Nook” - Yorkshire, depends on compensation owned
What is land use management (S)?
Controlling and restricting building in areas at risk of coastal erosion or flooding
What are some advantages of land use management?
- prevents further damage and costly defences
- encourages sustainable land use
- reduces insurance and maintenance cost
What are some disadvantages of land use management?
- difficult to implement in already developed areas
- can face resistance from developers and land owners
- does not protect existing infrastructure
How much does land use management cost?
Low (0-500,000 depending on scale)
