coastal change and conflict

Question 1

what is weathering?

Answer 1

breakdown of rock and material in situ by elements of the weather, chemicals and living organisms

Question 2

what is mass movement?

Answer 2

large-scale movements of material down a slope due to gravity e.g. rockfall, landslide, slumping

Question 3

describe the processes of wave action on coasts

Answer 3

• Hydraulic action – water is forced into cracks in the rock which compresses the air. When a wave breaks the compressed air blasts out and can force the rock apart
• abrasion – sediment is thrown against cliff by waves which wears the cliff away and chips off bits of rock
• attrition – loose sediment is swirled around by waves and collide with other sediment which get worn down into smaller around sediment
• Corrosion – salts and other acids in sea– water slowly dissolves a cliff

Question 4

what is a discordant coast and give an example

Answer 4

swanage Coast, dorset
•alternating hard and soft rocks at right angles to the coastline
•hard rock- difficult to erode forms headlands
•soft rock-easy to erode forms bays

Question 5

what is a concordant Coast and give an example

Answer 5

Lulworth coast, Dorset
•alternating hard and soft rocks parallel to the Coast
•one rock type evident at Coast
•if waves erode through hard rock a narrow entrance allows waves to erode soft rock forming a cove

Question 6

what are joints?

Answer 6

cracks in rocks where there is no displacement of the rock. Caused by cooling when rocks are formed or unloading when weight is taken off them as material above erodes

Question 7

what are faults?

Answer 7

cracks in rocks where there is displacement of the rock. Often caused by tectonic movements

Question 8

describe hard rock coasts and give an example

Answer 8

chalk cliffs, swanage bay, Dorset 
•20m tall almost vertical 
•smooth, cracks, some vegetation
•Wave cut notch and platform
•Lower rate of erosion

Question 9

describe soft rock coasts and give an example

Answer 9

sand and clay cliffs, Christchurch bay, Dorset
•15m tall, Low angle 45° steeper at top
•Uneven, some vegetation
•Beach, slumped material
•Wave action weakens base
•High rate of erosion

Question 10

describe a constructive wave

Answer 10

• Strong swash
• Week backwash
• Small wave amp
• Long wavelength
• Sand transported up beach and deposited on beach
• gently sloping beach
• Depositional landform

Question 11

describe a destructive wave

Answer 11

• Weak swash
• Strong backwash
• large wave amp
• short wavelength
• Sand is transported out to sea and eroded from beach
• Steep beach
• Erosional landform

Question 12

what is erosion?

Answer 12

breakdown of rock and sediment and its removal by wind, running water, glacier and wave action

Question 13

what is a spit?

Answer 13

when longshore drift pushes sediment out onto river it is deposited forming a long neck of sand and shingle

Question 14

what is a bar?

Answer 14

where a spit grows across a bay and can enclose the bay to create a Lagoon

Question 15

describe and explain the stages of longshore drift

Answer 15

• Wind – prevailing wind blows at oblique angle to coastline
• waves – causes waves to arrive at coast at a similar angle
• Swash – transport material up beach at oblique angle
• Backwash – transports material down beach at perpendicular angle
• repeated many times
• Overall movement – results in material being transported along shoreline

Question 16

describe and explain the conflicting views on how the coast should be managed for a named location

Answer 16

in favour –
• residence of Barton on Sea whose homes are in danger
• local tourism businesses like caravan parks, hotels - put in danger leading to a poor income liable for payment of clearance
• local politicians who want to support residents and businesses

against –
•Hampshires taxpayers who don’t live on the coast – paying for something which doesn’t help them and less money towards other services
•Environmentalists – all management destroys nature causing visual pollution

Question 17

explain the erosion of cliffs at the named location

Answer 17

• as it rains on the cliffs the rain percolates through the sand and is absorbed by the clay
• this weakens the clay and causes slumping
• The base of the cliff weakens as abrasion occurs

Question 18

explain the costs and benefits of hard engineering structure -seawalls

Answer 18

Wall of concrete at base of cliff or behind a beach
\+
• reflects waves back out to sea
• effective in preventing erosion 
•Easy to maintain and repair
-
• prevents easy access to beach
•Seawalls will have to be higher to cope with the rising sea levels in future – expensive

Question 19

explain the costs and benefits of hard engineering structure -groynes

Answer 19

wooden fences that run down the beach at right angles to the coast
+
•Larger beach – dissipates wave energy reducing erosion
-
• May increase erosion down drift
•Beaches disappear as sediment is prevented from reaching other locations

Question 20

explain the costs and benefits of hard engineering structure -rip rap

Answer 20

pile of hard rock boulders placed along base of cliff
\+
• natural – less visually polluting
• easy and cheap
-
•Doesn't prevent longshore drift

Question 21

explain the costs and benefits of soft engineering structure – Cliff grading

Answer 21

Cliff angle is lowered and profile smoothed out vegetation is planted
+
•Prevents slumping and degradation of cliff
• visually pleasing
-
• doesn’t prevent 100% erosion
• Long time to implement

Question 22

explain the costs and benefits of soft engineering structure – Cliff drainage

Answer 22

drainage pipes incorporated into cliff face
+
•Prevents saturation of the cliff – preventing slumping
-
• expensive
•Requires expert engineering to fit

Question 23

explain the costs and benefits of soft engineering structure – Beach nourishment

Answer 23

additional sand added to beach making it larger
+
• widens beach
• natural form
-
•Sediment removed from other parts of coastline