Lesson 11

Question 1

What is coastal retreat?

Answer 1

the coastline retreating

Question 2

Natural factors causing the coastline to retreat? (2)

Answer 2

geology of coast

marine and sub Ariel processes

Question 3

What is the most rapid rate of coastal recession? (5)

Answer 3

weakly consolidated rock
large destructive rocks
submergence of a coastline
large scale mass movement
constant weathering

Question 4

Human factors that influence coastal retreat? (2)

Answer 4

sea wall/groynes - stop erosion in certain place but continues further down
beach replenishment - can’t happen as sediment isn’t carried (stopping deposition) bigger waves erode further as beach isn’t built up

Question 5

What is offshore dredging?

Answer 5

dredging for sand and gravel for construction purposes (under UK government licence)

Question 6

How does offshore dredging cause problems? (2)

Answer 6

Less sediment to absorb wave energy so erosion rates increase.
Deeper water means waves have more power so they’re more destructive

Question 7

How does dreading of shallow seabeds have a negative impact on the environment? (2)

Answer 7

removing species and communities

increasing sediment levels - damage coral reefs

Question 8

What impact can increased deposition have? (3)

Answer 8

raise sediment levels
may affect sea level rise
isostatic sinking

Question 9

What impact can increased deposition have locally? (2)

Answer 9

local sea currents altered - waves larger

effect sediment balances and erosion

Question 10

What evidence is used?

Answer 10

computer modelling rather than measured data

Question 11

Example of human activity and coastal recession?

Answer 11

Lowestoft, resulted in beach loss

Question 12

How is the Nile delta facing retreat?

Answer 12

significant erosion on half of it

Question 13

Reasons for erosion on the Nile Delta?

Answer 13

salt intrusion due to sea rise and coastal flooding more frequent (due to climate change) - land loss

Question 14

How has Aswan dam effected the Nile Delta?

Answer 14

reduced sediment supply

Question 15

How do weather systems cause coastlines to retreat? (2)

Answer 15

high pressure (anticyclones) bring calmer conditions, smaller waves.
Low pressure (depressions) has a mixture of air masses at different temperatures.

Question 16

How does low pressure influence coastal retreat?

Answer 16

Air rises rapidly, strong winds anticlockwise creating larger waves.

Question 17

How does cold weather influence coastal retreat?

Answer 17

In winter the difference between the equator temperature and pole is greatest so depressions are strongest. Low pressure and fast speeds create destructive waves, more recession

Question 18

How does hot weather influence coastal retreat?

Answer 18

global warming added more heat to atmosphere, intensified low pressure systems. Erosion increase in winter

Question 19

How many tides does the UK experience a day?

Answer 19

2 high + 2 low

Question 20

When do high tides occur?

Answer 20

(spring) sun and moon aligned - gravitational pull strongest.

Question 21

When do low tides occur?

Answer 21

(neap) sun and moon at right angles - gravitational pull weakest. Occur twice every lunar cycle.

Question 22

What do tides determine?

Answer 22

When water will reach the shore

Question 23

What happens at high tides?

Answer 23

Waves more likely to reach the back shore and erode land faster. Combined with destructive storm waves erosion is at max

Question 24

What does wind direction determine?

Answer 24

wave direction. Prevailing dominate

Question 25

What is the fetch?

Answer 25

wind blown over a wave. (max distance a wave can travel with out being interrupted. (coasts with long fetch retreat faster)