Coasts

Question 1

What causes destructive wave and what are its characteristics?

Answer 1

Caused by large fetch where the backwash is stronger than the swash.
They are big and have higher energy.
They erode the coastline.

Question 2

What causes constructive wave and what are its characteristics?

Answer 2

Caused by short fetch where swash is stronger than backwash.
They are small gentle waves with low energy.
They deposit sediment.

Question 3

What is fetch?

Answer 3

The length of water a gust of wind has blown over, therefore the distance a wave travels.

Question 4

What are the four types of mass movement?

Answer 4

Rockfall
Mudflow
Rotational slip
Landslide.

Question 5

What is rockfall?

Answer 5

Created by the force of gravity and by freeze-thaw.
This loosens the rock.
Rock falls leaving a scree slope of rock beneath.

Question 6

What is mudflow?

Answer 6

It occurs on slopes higher than 10 degrees and is caused by heavy rain in areas of too low vegetation to hold saturated soil in place.
Rock beneath soil is permeable.
Are very dangerous.

Question 7

What is rotational slip?

Answer 7

Created by heavy rain which saturates soil on a curved surface with weakened rock.
Slowly slumps and slips onto curved plane.

Question 8

What is landslide?

Answer 8

Occur after periods of heavy rain as overlying rock becomes saturated.
Rock becomes heavy and liable to to slide.
Location changes likelihood of one occurring.

Question 9

What are the 6 types of weathering?

Answer 9

Biological, mechanical, chemical, freeze-thaw, pressure release, salt crystallisation.

Question 10

What is mechanical weathering?

Answer 10

Where big rocks are broken into smaller fragments due to expansion and contraction, caused by ice forming in the cracks.

Question 11

What is the prevailing wind?

Answer 11

The dominant direction of wind.

Question 12

How is a wave formed?

Answer 12

Wind blows over sea, causing ripples to form.
Ripples swell and approach land.
Sea becomes shallower and bottom of wave slows due to friction.
Top continues to travel and forms a crest.
Crest eventually topples over forming a breaking wave.

Question 13

What are the four types of transportation?

Answer 13

Traction, solution, saltation, suspension.

Question 14

What is saltation?

Answer 14

When small rocks and pebbles are bounced along the river bed.

Question 15

What is longshore drift?

Answer 15

When sediment is carried along the beach as a result of swash and backwash.

Question 16

What causes backwash to travel at a 90 degree angle to the beach?

Answer 16

Gravity.

Question 17

What are 4 depositional landforms?

Answer 17

Spit, tombolo, bay, beach.

Question 18

What are the 4 stages of wave-cut platform formation?

Answer 18

Wave erosion
Cliff collapse
Retreat
Bugger wave-cut platform.

Question 19

What causes sea level rise?

Answer 19

Thermal expansion, ice and glacial melt, post glacial rebound.

Question 20

What are the threats to Tuvalu?

Answer 20

King tides, storm surges, groundwater flooding.

Question 21

What are the social impacts of rising sea levels in Tuvalu?

Answer 21

• The government is required to plan evacuation of remaining 10,000 residents.
• Many people are forced away from homeland.
• Salt water intrusion is affecting agriculture and farmers.
• Cultures and traditions are being lost.
• Health problems, i.e. typhoid, from contaminated water is rising.
• The crop paluku is being destroyed and is a main source of carbohydrates.

Question 22

What are the economic impacts of rising sea levels in Tuvalu?

Answer 22

• Salt water intrusion is affecting ecosystems.
• Cash crops are destroyed by contamination, leading to a downturn in GDP.
• Coral reef bleaching leads to reduced fish stock and therefore fish industry is affected financially.

Question 23

What are the environmental impacts of rising sea levels in Tuvalu?

Answer 23

• Flooding and storm surges erode soils, leading to loss of plant and animal habitat.
• Warmer seas increase coral bleaching, decreasing important marine habitats.

Question 24

What are the political impacts of rising sea levels in Tuvalu?

Answer 24

• Tuvalu relies on aid from New Zealand.

- Government are trying to get their voice heard.

Question 25

Where is Tuvalu located?

Answer 25

Located in the Pacific Ocean, north of New Zealand.

Question 26

Where is Keyhaven Marsh?

Answer 26

Located in Southern Hampshire, behind Hurst Castle Spit.

Question 27

What are the threats to Keyhaven Marsh?

Answer 27

• Decrease in shingle supply-result of groynes in place up coast-supplied by longshore drift.
• Mud and sediment which is now not supplied was there to replenish marshes
• Marshes are now exposed causing rapid erosion.
• Decrease in pioneer species.
• Marshes absorb wave energy and protect coastline however if not there, coast will be under threat-areas of SSSI.

Question 28

How is this problem being managed?

Answer 28

• 550 m rock armour created.
• Spit nourishment with 300,000 cubic m of shingle.
• 100m rock revetment built.
• Sheep grazing encouraged to reduce decrease of pioneer species.

Question 29

What are the pioneer species in this marsh?

Answer 29

Spartina.

Question 30

Where is Aldbrough?

Answer 30

Located along the Holderness coast, north Yorkshire.

Question 31

What problems is Aldbrough facing?

Answer 31

• Terminal groyne syndrome
• No natural protection of cliffs
• Result of rock armour up coast in Mappleton
• Stops longshore drift and therefore deposition.
• Receding cliff-faces from cliff collapse
• Threat to villages
• Approx. 50 properties
• Landslides
• Soft geology

Question 32

What hard engineering methods has Mappleton used?

Answer 32

Rock armour and two groynes which is their shoreline management plan.
Costs 2 million pounds.

Question 33

What are the costs and benefits of Mappleton’s plan?

Answer 33

Costs:
-Require maintenance
-Very expensive
Benefits:
-Cliff faces protected