Coasts

Question 1

What is hydraulic action?

Answer 1

It is when pockets of air get trapped in cracks and crevices due to the force of waves hitting the cliff. This erodes away the cliff.

Question 2

What is abrasion?

Answer 2

When waves pick up stones and throw them against the cliff which erodes the cliff away.

Question 3

What is corrosion?

Answer 3

The dissolving of rocks by seawater

Question 4

What is attrition?

Answer 4

a process whereby the material carried by the waves becomes rounded and smaller over time as it collides with other material.

Question 5

What is weathering?

Answer 5

The break down of rocks caused by freeze-thaw and the growth of salt crystals by acid rain and the growth of vegetation roots.

Question 6

What is erosion?

Answer 6

The eroding away of rocks by wind and rain.

Question 7

What is mass movement?

Answer 7

The removal of cliff face material under the influence of gravity in the form of rock falls, slumping and landslides.

Question 8

what is a destructive wave?

Answer 8

A wave created in storm conditions, where waves with lots of energy, a steep wave front and a strong backwash, taking sand away from the beach.

Question 9

What is a constructive wave?

Answer 9

A wave created in calm weather, where waves have little energy, a strong swash but a weak backwash. This means sand is deposited on the beach.

Question 10

What is longshore drift?

Answer 10

The movement of material along a coast, where sediment is pushed up the beach by the swash and dragged back down by the backwash. It is pushed up at angles but comes down straight.

Question 11

How is a spit formed?

Answer 11

long shore drift carries sand along the shore until it reaches a river estuary where it gets pushed out into the river channel. The river flow halts the drift so sand is deposited forming a long sandy neck called a spit.

Question 12

How is a bar formed and what does it do?

Answer 12

Bars grow along the mouth of a bay due to long shore drift which can block small bays on the coast. This forms a lagoon.

Question 13

What are the benefits of sand dune regeneration?

Answer 13

Replanting grass encourages sand to be deposited and build up the height of the beach, it protects the coast from sea level rise and is relatively cheap and easy to plant.

Question 14

What are the disadvantages of sand dune regeneration?

Answer 14

People may trample on and kill plants and can only be planted on wide beach areas or would just get washed away.

Question 15

What are the benefits of seawalls?

Answer 15

The wall reflects waves back to sea and protects local businesses and houses.

Question 16

What are the disadvantages of sea walls?

Answer 16

They are quite costly, can prevent easy access to the beach and can still be eroded away.

Question 17

What are the benefits of revetments?

Answer 17

They break up incoming waves and protect the coastline. As well as being cheaper than a sea wall.

Question 18

What are the disadvantages of revetments?

Answer 18

They can restrict beach access and can be destroyed in big storms

Question 19

What are the benefits of Gabions?

Answer 19

They are a cheaper version of a sea wall and absorb wave energy.

Question 20

What are the disadvantages of Gabions?

Answer 20

They are no very strong and therefore don’t last as long as sea walls.

Question 21

What are the benefits of groynes?

Answer 21

They prevent long shore drift taking the sand of the beach and lower wave energy by making the beach larger.

Question 22

What are the disadvantages of groynes?

Answer 22

They may increase erosion downstream and can be quite expensive.

Question 23

What are some other soft coastal management strategies?

Answer 23

Natural retreat- leaving it to see what happens
Xmas trees- laid to hold sand on beach
Beach replenishment- sand is replaced