2.10. Hard (traditional) Engineering Strategies

Question 1

What are groynes?

Answer 1

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

Question 2

What is the cost of groynes?

Answer 2

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

Question 3

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

Answer 3

• 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

Question 4

What are sea walls?

Answer 4

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

Question 5

What is the cost of sea walls?

Answer 5

£6,000 per metre

Question 6

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

Answer 6

• 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

Question 7

What is rip-rap/rock armour?

Answer 7

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

Question 8

What is the cost of rip rap/rock armour?

Answer 8

£100,000-£300,000 per 100m

Question 9

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

Answer 9

• 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

Question 10

What are revetments?

Answer 10

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

Question 11

What is the cost of revetments?

Answer 11

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

Question 12

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

Answer 12

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

Question 13

What is offshore breakwater?

Answer 13

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

Question 14

What is the cost of offshore breakwater?

Answer 14

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

Question 15

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

Answer 15

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

Question 16

What are gabions?

Answer 16

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

Question 17

How much to gabions cost?

Answer 17

£110 per metre (cheap)

Question 18

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

Answer 18

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