The Coastal Zone

Question 1

What is a fetch?

Answer 1

A fetch is the length of water the wind blows over.

Question 2

What is swash?

Answer 2

Swash is the movement up the beach by the wave.

Question 3

What is backwash?

Answer 3

Backwash is the movement of the wave back down the beach.

Question 4

What is the crest?

Answer 4

The crest is the top of the wave.

Question 5

How is a wave formed?

Answer 5

In open sea, waves ‘bob’ up and down in a circular orbit. It does this because there is no friction from the sea bed. When the wave approaches the coastline, there is forward movement of the wave as it breaks and washes up the beach. It does this because there is no friction from the seabed which therefore slows down the base of the wave and the top of the wave carries on and spills over.

Question 6

What is the movement of wave change from deep to shallow water?

Answer 6

In deep water, the waves do circular orbits in the water because there is no friction. Where as, when it gets to the shallow water, the friction from the seabed slows down the base of the wave and as the top is still going fast, it causes the wave to break.

Question 7

What are the 4 characteristics of a constructive wave?

Answer 7

• small in height
• low energy
• strong swash
• weak bashwash

Question 8

What are the 4 characteristics of a destructive wave?

Answer 8

• large in height
• high energy
• weak swash
• strong backwash

Question 9

What is attrition?

Answer 9

Rocks and pebbles bump into each other to break apart and become smaller and smoother.

Question 10

What is corrosion (solution)?

Answer 10

Where some cliffs that are made of rock dissolve in water.

Question 11

What is corrasion (abrasion)?

Answer 11

When waves carrying sand and pebbles scrape away at the cliffs to make them smoother like sandpaper.

Question 12

What is hydraulic action?

Answer 12

When waves break into the cliffs forcing air into cracks and blasting the rocks apart.

Question 13

What is long shore drift?

Answer 13

The current which transports sediments such as mud, sand, and pebbles along the coastline. It is controlled by the direction of the dominant wind.

Question 14

What is deposition?

Answer 14

When the sea loses energy, it drops the sand, rock particles and pebbles it has been carrying.

Question 15

What is transportation?

Answer 15

Moving eroded materials, e.g. stones, sand or shingle by the waves from one place to another.

Question 16

How are spits formed?

Answer 16

Overtime, long shore drift deposits sand and shingle in front of a river mouth/estuary. Due to the current from the river, the deposited sand and shingle can’t cover the river mouth, so instead is shaped.

Question 17

How are bars formed?

Answer 17

Originally there are two headlands. Due to long shore drift the deposited sand and shingles join up the who headlands with a bar ad the water behind that is a lagoon.

Question 18

What is a lagoon?

Answer 18

A lagoon is seawater with no current.

Question 19

How are tombolos formed?

Answer 19

A tombolo is formed when long shore drift connects two islands together which deposited sand and shingle.

Question 20

How are cliffs formed?

Answer 20

Cliffs begin to form when the destructive waves attack the bottom of the rock face between high and low water marks.

Question 21

How are wave-cut notches formed?

Answer 21

Destructive waves attack the bottom of the rock face between high and low water marks. The waves erode the cliff face formed a wave-cut notch.

Question 22

How are wave-cut platforms formed?

Answer 22

Weather weakens the top of the cliff.
The sea attacks the base of the cliff forming a wave-cut notch.
The notch increases in size causing the cliff to collapse.
The backwash carries the rubble towards the sea forming a wave-cut platform.
The process repeats and the cliff continues to retreat.

Question 23

How are headlands formed?

Answer 23

Headlands are formed when the sea attacks a section of coast with alternating bands of hard and soft rock. The stronger rock resists waves attack longer and they therefore stand out as prominent rocky headlands.

Question 24

How are bays formed?

Answer 24

Where rocks of different hardness and resistance to erosion meet the sea, the weaker rocks are eroded back more quickly to form bays.

Question 25

What are the stages of caves, arches, stacks and stumps?

Answer 25

• Air and water gets into little cracks in the cliff side and this expands before breaking (hydraulic action). The expansion then forces the crack in the cliff to become larger before it expands into a cave.
• More erosion from the sea due to hydraulic power and corrosion then expands the cave into an arch.
• As the arch gets bigger and bigger from more hydraulic action, the top can no longer support itself and collapses forming a stack.
• Erosion attacks the bottom of the stack therefore making it smaller and weaker until it collapses leaving behind a stump.

Question 26

Name an example of an rock in the caves, arches, stacks and stumps process?

Answer 26

Old Harry

Question 27

What are the 3 types of management?

Answer 27

• hard engineering
• soft engineering
• managed retreat

Question 28

What is hard engineering?

Answer 28

It involves artificial structures to control forces of nature. They are expensive, involve high maintenance costs, they’re destructive and unnatural.

Question 29

What is soft engineering?

Answer 29

They are ‘low key’ with low maintenance costs. They are made out of natural resources.

Question 30

What is the advantages and disadvantages of sea walls?

Answer 30

advantages:
- effective at stopped the sea
- often has a walkway for people to walk along
disadvantages:
- can be obstructive
- is unnatural
- very expensive and high maintenance costs

Question 31

What is the advantages and disadvantages of groynes?

Answer 31

advantages:
- results in a bigger beach
- useful structures
- not too expensive
disadvantages:
- often lead to increased rate of erosion elsewhere
- unnatural

Question 32

What is the advantages and disadvantages of rock armour?

Answer 32

advantages:
- relatively cheap and easy to maintain
- can provide interest to the coast often used for fishing
disadvantages:
- can be expensive to transport
- don't fit in with the local geology
- can be obstructive

Question 33

What is the advantages and disadvantages of beach nourishment?

Answer 33

advantages:
- relatively cheap and easy to maintain
- blends in
- increases tourists potential
- bigger beach
disadvantages:
- needs constant maintenance

Question 34

What is the advantages and disadvantages of dun regeneration?

Answer 34

advantages:
- maintains a natural coastal environment
- is relatively cheap
disadvantages:
- is time-consuming to plant the marram grass
- people don’t always respond well
- can be damaged by storms

Question 35

What is the advantages and disadvantages of managed retreat?

Answer 35

advantages:
- cheap option
- creates a much needed habitat for wildlife
disadvantages:
- land will be lost if flooded
- landowners will need to be compensated

Question 36

What is the costs of sea walls, groynes, rock armour, beach nourishment, dune regeneration and managed retreat?

Answer 36

sea walls: up to £10m per km
groynes: up to £5000 per metre
rock armour: approx £1000-4000 per metre
beach nourishment: approx £3000 per metre
dune regeneration: approx £2000 per 100m
managed retreat: £5000-10000 per hectare