2.10. Hard (traditional) Engineering Strategies Flashcards

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1
Q

What are groynes?

A

Timber or rock structures built at right angles to to the coast

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2
Q

What is the cost of groynes?

A

£5,000- £10,000 each at 200 metre intervals (not as expensive as other strategies)

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3
Q

What do the groynes do & how long do they last?

A
  • longevity: lasts 20-25 years if well maintained
  • builds up the beach which improves tourist potential
  • can be unattractive
  • need lots of maintenance to ensure sediment isn’t getting through holes or cracks
    Deprives other areas of sediment, increasing erosion elsewhere
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4
Q

What are sea walls?

A

Stone or concrete walls at the foot of a cliff, or at the top of a beach

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5
Q

What is the cost of sea walls?

A

£6,000 per metre

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6
Q

What do sea walls do & how long do they last for?

A
  • longevity: 30-50 years
  • are ugly and intrusive to the landscape
  • highly effective
  • can provide benefits for tourism as they create walkways
  • expensive to maintain
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7
Q

What is rip-rap/rock armour?

A

Large rocks placed at the foot of a cliff or top of a beach

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8
Q

What is the cost of rip rap/rock armour?

A

£100,000-£300,000 per 100m

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9
Q

What does rip rap/rock armour do/ how long does it last?

A
  • if well maintained can last 25-30 years
  • effective at reducing wave energy
  • cheaper than sea walls
  • cheap and easy to maintain
  • dangerous when people are walking on them
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10
Q

What are revetments?

A

A slope or ramp like structure that breaks up wave energy.

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11
Q

What is the cost of revetments?

A

Up to £4,500 per metre (cost effective compared to other hard engineering strategies)

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12
Q

What do revetments do/ how long do they last for?

A
  • longevity: 30-50 years
  • need high levels of maintenance - wood rots
  • unnatural
  • slopes are dangerous
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13
Q

What is offshore breakwater?

A

A partly submerged rock barrier designed to break up the waves before they reach the coast

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14
Q

What is the cost of offshore breakwater?

A

Similar to rock armour depending on materials
£100,000-£300,000 per 100m

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15
Q

What does offshore breakwater do/ how long does it last for?

A
  • longevity: 30- 50 years
  • effective permeable barrier
  • high maintenance
  • visually unappealing
  • away from beach so doesn’t disrupt tourist potential
  • can create navigation barriers
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16
Q

What are gabions?

A

A cage of rocks that is put at the edge of the coast to reduce erosion

17
Q

How much to gabions cost?

A

£110 per metre (cheap)

18
Q

What do gabions do/ how long do they last for?

A
  • longevity: 20-25 years
  • cheap and easy to maintain
  • people will walk on the cages (not good)