Coasts:: Coastal Management - Traditional Approaches

Question 1

What is hard engineering?

Answer 1

Hard engineering involves the building of entirely artificial structure using various materials to reduce or stop the impact of coastal processes.

Question 2

Why may different stakeholders not be happy with hard engineering along the coast?

Answer 2

It is an unsustainable method of management:

• expensive
• require constant maintenance
• harm the environment

Question 3

What is soft engineering?

Answer 3

Soft engineering methods try to work with the physical and natural processes within an area to protect the coast

Question 4

Describe a sea wall

Answer 4

A concrete barrier along the coast which absorbs the energy of the waves. Some can be curved to deflect the power of the waves.

Question 5

Advantages of sea walls

Answer 5

• very effective
• will prevent erosion
• easily made

Question 6

Disadvantages of sea walls

Answer 6

• deflecting waves can undermine foundations
• requires maintenance and repair
• expensive to maintain
• ugly and unnatural

Question 7

Cost of sea walls

Answer 7

£5000 per metre

Question 8

Describe groynes

Answer 8

Wooed fences or walls made from piles of rocks built out into the sea.

Question 9

How do groynes protect the coast?

Answer 9

They reduce the rate of longshore drift by trapping material on one side. This extra beach then protects the coast from the sea.

Question 10

Advantages of groynes

Answer 10

• works with natural processes
• increases tourist potential
• relatively low costs
• easily repaired

Question 11

Disadvantages of groynes

Answer 11

• can increase erosion rates further down the coast

- unattractive

Question 12

Cost of groynes

Answer 12

£1000 per metre

£5000-£10,000 each (200m intervals)

Question 13

Lifespan of groynes

Answer 13

30-40 years

Question 14

Lifespan of sea walls

Answer 14

30-50 years

Question 15

Describe rip-rap

Answer 15

Large rocks placed at the foot of a cliff or at the top of a beach. It forms a permeable barrier to the sea, breaking up the waves but allowing some water to pass through.

Question 16

Advantages of rip-rap

Answer 16

• easy to construct and maintain
• used for recreation e.g fishing, sunbathing
• uses natural resources

Question 17

Disadvantages of rip-rap

Answer 17

• some erosion takes place
• can be intrusive
• looks out of place with local geology
• dangerous to climb on

Question 18

Cost of rip-rap

Answer 18

£1000-£3000 per metre

Question 19

Lifespan of rip-rap

Answer 19

120 years but could be removed in heavy storms

Question 20

Describe revetments

Answer 20

Sloping wooden or concrete rock structures places at the foot of a cliff or the top of a beach. They absorb the wave’s energy and trap beach material.

Question 21

Advantages of revetments

Answer 21

• cheap to build

- easily made

Question 22

Disadvantages of revetments

Answer 22

• unnatural looking
• can need high levels of maintenance
• not as durable as sea wall (limited lifespan)
• doesn’t give total protection to base of cliff

Question 23

Cost of revetments

Answer 23

£4500 per metre

Question 24

Lifespan of revetments

Answer 24

Concrete - 30 years

Wooden - 10 years

Question 25

Describe offshore breakwaters

Answer 25

Partly submerged rock barrier built parallel to the coast, designed to break the waves before they reach the shore, reducing wave energy.

Question 26

Advantages of offshore breakwaters

Answer 26

- effective permeable barrier - cheap to build - doesn't spoil the beach

Question 27

Disadvantages of offshore breakwaters

Answer 27

- visually unappealing - potential navigation hazard - very expensive - can be tricky to maintain

Question 28

Cost of offshore breakwaters

Answer 28

£1.3 million for one (but depends on materials used)

Question 29

Describe beach replenishment

Answer 29

The addition of sand or pebbles to an existing beach to make it high or wider. The sediment is usually dredged from the nearby seabed.

Question 30

Advantages of beach replenishment

Answer 30

- looks natural and blends in with existing beach | - creates a bigger beach, increasing tourist potential

Question 31

Disadvantages of beach replenishment

Answer 31

- needs constant maintenance because of natural processes of erosion and longshore drift - relatively expensive - dredger creates noise pollution, upsets tourism and kills marine life from sea bed

Question 32

Cost of beach replenishment

Answer 32

£300,000 per 100m

Question 33

Describe managed retreat

Answer 33

Allowing the coast to take back the land, by removing existing sea defences and allowing the land behind them to flood

Question 34

Advantages of managed retreat

Answer 34

- marshland will form, creating habitats - marshland will act as a natural sea defence protecting the land behind it from erosion - cost effective

Question 35

Disadvantages of managed retreat

Answer 35

- can cause conflict over which land should be flooded - agricultural land is lost - farmers or landowners need to be compensated

Question 36

Example of managed retreat

Answer 36

Alkborough Flats, Lincolnshire

Question 37

Describe cliff regrading and drainage

Answer 37

Reducing the angle of a cliff to stabilise it. | Drainage removes excess water to prevent landslides and slumping.

Question 38

Advantages of cliff regrading and drainage

Answer 38

- cost effective | - very useful on clay and loose rock cliffs

Question 39

Disadvantages of cliff regrading and drainage

Answer 39

- drains may become new lines of weakness - dry cliffs may produce rockfalls - effectively causes cliff to retreat, so some homes may need to be demolished

Question 40

Example of cliff regrading and drainage

Answer 40

Mappleton, Holderness

Question 41

Describe dune stabilisation

Answer 41

Marram grass can be planted to stabilise dunes. Areas can be fenced off to keep people off newly planted dunes.

Question 42

Advantages of dune stabilisation

Answer 42

- maintains a natural coastal environment - provides important wildlife habitats - cheap and sustainable

Question 43

Disadvantages of dune stabilisation

Answer 43

- time consuming to plant marram grass - people may respond negatively to being kept off certain areas - may still be eroded if people ignore signs

Question 44

Cost of dune stabilisation

Answer 44

£200-£2000 per 100m

Question 45

Example of dune stabilisation

Answer 45

Muir Beach, California

Question 46

According to UNEP, how far from the coast do half of the world's population live?

Answer 46

60km