Coastal hazards and their management

Question 1

What are some types of hard engineering?

Answer 1

• sea walls
• gabions
• groynes
• rock armour

Question 2

What are the advantages of sea walls?

Answer 2

• effective at protecting the base of the cliff

- sea walls usually have promenades so people can walk along them

Question 3

What are the disadvantages of sea walls?

Answer 3

• waves are still powerful and can break down and erode the sea wall
• expensive: approx. £2000 a metre

Question 4

What are the advantages of rock armour?

Answer 4

• cheaper than a sea wall and easy to maintain

- can be used for fishing

Question 5

What are the disadvantages of rock armour?

Answer 5

• look different to the local geology, as rock imported from other areas
• the rocks are expensive to transport
• can gather rubbish and look unsightly

Question 6

What are the advantages of gabions?

Answer 6

• cheap

- absorb wave energy

Question 7

What are the disadvantages of gabions?

Answer 7

• not very strong

- look unnatural

Question 8

What are the advantages of groynes?

Answer 8

• the build a beach

- trap sediment being carried by longshore drift

Question 9

What are the disadvantages of groynes?

Answer 9

• look unattractive

- by trapping sediment they starve beaches further down the coastline, increasing rates of erosion elsewhere

Question 10

What are sea walls?

Answer 10

concrete walls that are placed at the foot of a cliff to prevent erosion, they are curved to reflect the wave energy back into the sea.

Question 11

What is rock armour?

Answer 11

large boulders placed at the foot of a cliff, they break waves and absorb their energy

Question 12

What are gabions?

Answer 12

rocks held in mesh cages and placed in areas affected by erosion

Question 13

What are groynes?

Answer 13

wooden or rock structures built at right angles into the sea

Question 14

What are some types of soft engineering?

Answer 14

• beach nourishment
• beach reprofiling
• sand dune stabilisation

Question 15

What are the advantages of beach nourishment?

Answer 15

• blends in with the existing beach

- larger beaches appeal to tourists

Question 16

What are the disadvantages of beach nourishment?

Answer 16

• needs to be constantly replaced

- sand has to be brought from elsewhere

Question 17

What are the advantages of beach reprofiling?

Answer 17

• cheap and simple

- reduces the energy of the waves

Question 18

What are the disadvantages of beach reprofiling?

Answer 18

• only works when wave energy is low

- needs to be repeated continuously

Question 19

What are the advantages of sand dune stabilisation?

Answer 19

• maintains natural-looking coastline
• relatively cheap
• encourages wildlife and vegetation to establish and thrive

Question 20

What are the disadvantages of sand dune stabilisation?

Answer 20

• can be damaged by storm waves

- areas have to be zoned off from the public

Question 21

What is beach nourishment?

Answer 21

when sand is pumped onto and existing beach to build it up

Question 22

What is beach reprofiling?

Answer 22

when the sediment is redistributed from the lower part of the beach to the upper part of the beach

Question 23

What is sand dune stabilisation?

Answer 23

when marram grass is planted on sand dunes and stabilises the dunes, and helps to trap sand to build them up

Question 24

What are the two different approaches to coastal management?

Answer 24

• hold the line

- retreating the line

Question 25

What is holding the line?

Answer 25

this is when coastal defences are built or maintained to protect a coastline against the impacts of sea level rise and coastal erosion/flooding. Often a mixture of hard and soft engineering strategies is used. This is often expensive but popular with local residents.

Question 26

What is retreating the line?

Answer 26

this is when people move out of the dangerous, most vulnerable areas and there is no defence against the elements. The coastline is often eroded inland creating salt marshes. This is less expensive but not always popular with local residents.