2B.11A Flashcards

1
Q

Give examples of hard engineering approaches

A

groynes, sea walls, rip rap, revetments, offshore breakwaters

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2
Q

What are the two main effects of hard engineering

A

economically costly and directly alter physical processes and systems

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3
Q

Pros of sea wall/groynes/recurved sea wall

A
  • Effective – land protected, land stable
  • Income will be possible , e.g. From tourism
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4
Q

Cons of sea wall/groynes/recurved sea wall

A
  • Expensive, millions of pounds
  • Need maintenance continually
  • Visual impact is poor – can harm tourism
  • Interfere with natural processes, e.g. LSD can prevent beach formation downdrift (terminal groyne syndrome)
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5
Q

Pros of beach nourishment/managed retreat

A
  • Works with nature – allows natural processes to work
  • Replicates natural environment where possible – means tourism can continue etc.
  • Doesn’t damage natural processes
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6
Q

Cons of beach nourishment/managed retreat

A
  • Can be ineffective, or need continued resupply of materials
  • People can lose homes and land value sharply declines (e.g. With managed retreat)
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7
Q

How many people live on the cuaseway coast of portballintrae

A

734

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8
Q

Describe the historic fishing village of portballintrae

A
  • Small fishing pier since 1760
  • Damaged by storms in 1830
  • Replaced in 1895 and enlarged in 1970
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9
Q

Describe fetch right now at portballintrae

A

Wave fetch from Atlantic, refracted around Ireland

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10
Q

Describe growth at portballintrae

A

Rapid growth since the 1970s
- Mainly 2nd homes
- 3db bungalow = £300,000
- Potentially a Trump Golf Course

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11
Q

One bad thing at portballintrae

A

huge amount of beach removal

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12
Q

Describe basic geology at portballintrae

A
  • Reworked glacial sands
  • Rocky headlands
  • High energy waves (2k km fetch)
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13
Q

Main changes over time at portballintrae

A
  • Alterations since 1800s
  • Lost 1,000m2/yr
  • Sand beaches now very boulder orientated
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14
Q

Why hasn’t hard engineering worked:
what processes have been disrupted at portballintrae

A
  • Leslie’s Pier – built in 1760, rebuilt 1895
  • by diffracting incoming waves, it’s created a low-energy zone in the shadow
  • Therefore, waves attack centre of the bay
  • Longshore drift from centre to East, removing sand
  • Rip current takes sediment out into deeper water
  • Beach is deprived of sandy sediment
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15
Q

When should you use hard engineering

A
  • As part of Hold the Line / Advanced the Line
  • When the cost of the defences < economic benefits
    E.g. infrastructure – (Easington Gas Terminal / Dawlish railways line
  • If there’s political advantage, e.g. not cutting off a community
  • If there are coastal habitats / environments worth protecting

BUT: if engineering would damage a sensitive coastal habitats?
OR: if erosion / mass movement rates are very very high?

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16
Q

What other methods are being used at portballintrae

A
  • Groynes built in 1904, upgraded and added in 1970s and 1997
  • Centre of bay continued to retreat
  • Sand nourishment / barrier at the base of the cliffs
  • Beach continued to fall
17
Q

What could be used at portballintrae

A
  • EITHER: offshore breakwater in centre of bay (looks ugly)
  • OR: remove engineering (too ‘controversial’ for expensive home owners)
18
Q

check out hard engineering descriptions on weebly a levle edexcel geo

A

dd

19
Q

Pros of hard engineering

A

-It’s obvious to at-risk people that something is being done to protect them, its reassuring
- A ‘one-off’ solution that could protect a coastline for decades

20
Q

Cons of hard engineering

A
  • Costs are usually very high, and there are still ongoing maintenance costs
  • Even very carefully designed engineering solutions are prone to failure
  • Coastlines are made visually unattractive and the needs of a coastal ecosystem are usually overlooked
  • Defences built in one place frequently have adverse consequences further along the coast