2.10 - Guinea's Coastline

Question 1

Effects Of Rock Hardness On Coastline

Answer 1

Softer and uncemented sediment/rock are vulnerable to cliff retreat. Igneous have a stronger crystalline structure where joints and fractures in the rock create a complex coastline.

Question 2

Geological Orientation

Answer 2

Discordant coasts have different rates of erosion, resulting in headlands and bays. Headlands concentrate wave energy (refraction) resulting in more complex erosion features.

Question 3

Wave Type/Energy

Answer 3

Water is driven into cracks in rocks, compressing air that is already there, creating an explosive blast. Bombardment and blasting is made worse by sediment chucked at the coast.

Question 4

Rock Breakdown/Erosion

Answer 4

e.g. hydraulic acction/attrition/abrasion, often together with other subaerial. Some mechanical processes expose the coastline to wave and subaerial processes.

Question 5

Rock Layers

Answer 5

Differences within the cliff face affects level of resistance, different rates of erosion and overtime cause landslides.

Question 6

Wave-Cut Erosion

Answer 6

Eroded cliffs leave a wave-cut platofrm, which can be covered by low tide, leading to abrasion. Abrasion and limestone solution creating a rocky foreshore.

Question 7

West Africa

Answer 7

700m of erosion in 40 years particularly in NW Guinea
10 cm of SLR since 1950, 1m by 2100.
Urbanisation is high along the coast - fishing, tourism and commerce.

Question 8

SLR Coastal Recession

Answer 8

Waves tend further up the beaches and cliffs. This affects coasts made of soft sediments.

Question 9

Swell Waves Coastal Recession

Answer 9

Stormy monsoon months. Wave heights of 3m and 3.8m damage leading to unemployment for Kenyan workers.

Question 10

Swell Waves

Answer 10

Waves that come from different area to where they were generated.

Question 11

Mangrove Deforestation Coastal Recession

Answer 11

Less mangroves absorb less wave energy. Mangroves are used for the wood to cook fish, they are also used as supply.

Question 12

Diamond Mining Coastal Recession

Answer 12

Gravel extraction from rivers, where diamonds are retrieved. Gravel and sediment is not always being returned.

Question 13

Sand Extraction Coastal Recession

Answer 13

It’s removed from the river for housing, meaning sediment isn’t transported to the coastline, and therefore there’s increased vulnerability to coastal recession.

Question 14

Coastal Management/Dredging

Answer 14

Removal of materials for ports and beach nourishment. Deep water, energy is retained. Destroy marine habitats, disrupt functioning food chains and damage environmental habitats.

Question 15

Sea Defence Vs Mangrove Deforestation

Answer 15

These fators counteract one another, as you need defences to counter impacts of removing mangroves.

Question 16

Expensive Coast Management Vs Offshore Dredging

Answer 16

IN order to counter the removal of material you need coastal expensive coastal management.

Question 17

Diamond Mining Vs Strong Waves

Answer 17

Strong waves increase the possibility of coastal recession, it becomes easier to mine into the diamonds as a result.

Question 18

Offshore Dredging Vs Strong Waves

Answer 18

Removing material increases the imapct of the strong waves more wave energy, so more erosion.

Question 19

SLR vs Mangrove Deforestation

Answer 19

Removed the physical barrier, allowing the sea level to have a larger impact.

Question 20

Offshore Dredging Vs Mangrove Defrestation

Answer 20

Offshore dredging nourishes the land but increases impact of wave energy. Mangrove deforestation means less wave energy is absorbed.

Question 21

Coastlines Can Recover From Human Activity

Answer 21

Mappleton Coastal Managemnt scheme - 2 million spent
Hard Engineering - Norwegian granite rich armour at base.
Two rock groynes to stop material from moving along
Erosion has decreased and cliff risk has reduced.

Question 22

Coastlines Can’t Recover From Human Activity

Answer 22

Alexandra Flooding, 7 million displaced, sea defences didn’t work, farming industries cost.
Recreation and tourism makes up 70% of tourism in T&T.
Coastal management is only effective if the coastal processes stay the same.
Climate change humans move them over time.