Section C - Coastal Landscapes

Question 1

How are waves formed and what happens when they approach the shore?

Answer 1

Friction from the wind causes surface water to ripple and the stretch of water the wind blows over is the stretch and the longer the stretch and the stronger the wind the larger the wave.
Waves start out at sea with a circular orbit but shore friction slows the base of the wave causing elliptical orbital waves until the top of the waves breaks over.

Question 2

Name key characteristics of Constructive Waves.

Answer 2

swash is bigger than backwash leading to deposition, low wave heights, low wave frequencies, and gentler-sloping beach, created by storms far out at sea.

Question 3

Name key characteristics of Destructive Waves.

Answer 3

the backwash is stronger than swash leading to erosion, high wave crest, more frequent waves, and a steeper beach profile.

Question 4

Name and explain the 3 types of coastal weathering.

Answer 4

Chemical weathering- chemicals in rainwater dissolve the rocks
Mechanical or freeze-thaw weathering- water gets into rocks and freezes so it expands and widens the crack until it eventually breaks
Biological weathering- roots grow to apply constant pressure to rocks, animals burrow into the ground weaken and break rocks

Question 5

Name and explain the 5 types of coastal mass movement.

Answer 5

Rockfall- when large amounts of rocks slide down a cliff due to freeze-thaw weathering
Landslide- occurs when loose sediments or dirt fall down a slope
Mudflow- develop when water rapidly accumulates in the ground resulting in a surge of saturated rock, earth and debris as vegetation can no longer support it
Slides- material shifts in a straight line
Slumps- material shifts with rotation

Question 6

Name and explain the 4 types of coastal erosion.

Answer 6

Hydraulic Power- water enters cracks in cliff face compressing air and causing pressure extending the crack
Corrosion- weak acids within the sea dissolve certain rock types slowly
Abrasion- rocks carried within the sea thrown onto cliffs and beaches breaking each other
Attrition- rocks carried within the sea hit against each other smoothing down

Question 7

Name and explain the 4 main types of coastal transportation.

Answer 7

Traction- rolling of rocks and stones along the sea bed, most energy
Saltation- leap frog jumping of rocks along the sea bed, second-most energy
Suspension- fine materials suspended within the water mass, second least energy
Solution- materials dissolved within the water, the least energy

Question 8

Explain Coastal Deposition.

Answer 8

occurs when the current slows down due to frictional forces depositing materials onto the coast

Question 9

Explain Longshore Drift.

Answer 9

swash comes at an angle due to prevailing wind and backwash comes straight back so materials move in a zig-zag fashion along the coast

Question 10

Name and explain the 3 types of rocks.

Answer 10

Sedimentary- fish/plants die and sink and due to pressure forms rocks, the weakest rock
Igneous- inland lava cools forming granite and in water forms basalt, medium rock
Metamorphic- rocks morphs and change due to continuous heat and pressure over a long time to form really hard rock, the hardest rock

Question 11

What is a Discordant Coastline?

Answer 11

made up of hard and soft rock perpendicular to the coast promoting various erosion rates influencing the formation of headlands and bays

Question 12

What is a Concordant Coastline?

Answer 12

make of hard and soft rock parallel to coast so erode at the same rate unless the hard outer rock been punctured resulting in rapid erosion of the soft rock behind it

Question 13

Explain the formation of Caves; Arches; Stacks; Stumps.

Answer 13

Wave starts to erode headland until it forms a fault in the cliff where it will break away into a cave which will eventually collapse into an arch
The arch bridge will fall down soon leaving behind a stack that will continue to erode leaving a stump.

Question 14

Explain the formation of a wave-cut platform.

Answer 14

Wave creates fault in the bottom of the cliff referred to as a wave-cut notch which will grow until the supported cliff will collapse and retreat
Carries on until it creates a wave-cut platform, during high tides it is inundated while in low tides there is minimal erosion as water retreats

Question 15

Explain the formation of a Beach.

Answer 15

Due to constructive waves and coastal deposition which mainly occurs in bays as most friction is created there, it leads to the formation of beaches
They are under constant change from processes like longshore drift or when exposed to destructive waves

Question 16

Explain the formation of Spits and Bars.

Answer 16

Longshore drift carries materials up the coast until it builds up behind a headland which causes coastal deposition as more friction is being created until it eventually forms a spit or a bar when it blocks a river/bay from the sea

Question 17

Explain the formation of Sand Dunes.

Answer 17

Natural/Artificial obstacles cause materials that are suspended within the wind to be deposited forming embryo dunes that influence tough plants known as pioneer seeds such as marram grass to get deposited here and start growing thereby the root helps stabilise it.
As the plant dies it provides nutrients and humus improving the soil and promoting more complex plant forms until eventually leading to climatic climax vegetation whereas in the UK it would be the forest.

Question 18

Name and Explain 4 Dorset Coast Coastal Landscapes Examples.

Answer 18

Durdle Door- an example of an arch that is formed on a concordant coastline. A band of soft limestone rock was eroded quickly and wave action opened a crack on the side of the headland
Lulworth Cove- is a small bay where a band of limestone was eroded and so was the band of clay that formed the bay.
Chesil Beach- a bar is presently formed by longshore drift with a lagoon behind it
Swanage Bay and The Foreland- formed on a discordant coastline where bays formed where soft rock eroded (clay and sandstone) and a headland made of harder rock (chalk) called the Foreland. Near it is Old Harry (Stack) and Old Harry’s Wife (Stump)

Question 19

What are the 3 differences between Soft Engineering and Hard Engineering coastal defences?

Answer 19

Soft engineering defines natural defences, typically considered inexpensive, long term and sustainable, whereas hard engineering represents artificial structures that are arguably short term, expensive and unsustainable solutions to coastal erosion.

Question 20

What are the 4 main hard engineerings and the 2 main soft engineering coastal defence

Answer 20

Hard Engineering- Sea Wall, Gabions, Rock Armour, Groynes

Soft Engineering- Beach Nourishment and reprofiling, Dune Regeneration

Question 21

Explain and mention benefits + costs of Sea Wall.

Answer 21

Explain- made of hard materials that reflect waves back to sea
Benefit- prevents erosion to the coast and acts as a barrier to flooding
Cost- creates strong backwash that erodes under the wall, expensive to build and maintain

Question 22

Explain and mention benefits + costs of Gabions

Answer 22

Explain- a wall of wire cages filled with rock usually at foot of the cliff
Benefit- absorb wave energy so reduces erosion and is cheap and easy to build
Cost- ugly and wire cages can corrode over time

Question 23

Explain and mention benefits + costs of Rock Armour

Answer 23

Explain- boulders piled up along the coast, sometimes called rip-rap
Benefit- absorb wave energy reducing erosion and flooding, fairly cheap defence
Cost- boulders can be moved by strong waves so need to be replaced

Question 24

Explain and mention benefits + costs of Groynes

Answer 24

Explain- fences built at right angles to the coast and trap materials transported by longshore drift
Benefit- create a wider beach that slows waves and gives greater protection from flooding and erosion. Fairly cheap defence
Cost- starves beach of sand further down the coast leading to narrower beaches that don’t protect the coast very well leading to greater erosion

Question 25

Explain and mention benefits + costs of Beach Nourishment and Reprofiling

Answer 25

Explain- sand and shingle from elsewhere or from lower down the beach are added to the upper parts of the beach
Benefit- Creates wider beach which slows the wave and gives greater protection against flooding and erosion
Cost- taking materials from the seabed can kill organisms like sponges and corals and is very expensive so has to be repeated

Question 26

Explain and mention benefits + costs of Dune Regeneration

Answer 26

Explain- restoring or creating sand dunes by nourishment or by planting vegetation to stabilise the sand
Benefit- dunes create a barrier between sea and land and stabilisation is cheap
Cost- protection is limited to small areas and nourishment is very expensive

Question 27

Explain Managed Realignment and highlight how it influences the formation of coastal wetlands/salt marshes.

Answer 27

Used to create intertidal zones of salt marshes
Punch holes through existing old embankments allow areas of land to flood which acts as a buffer against erosion in future flood events however although its sustainable and natural it causes land loss
Flooding of coastal lowlands from rising sea levels has created broad coastal marshes that are protected from wave action by barrier islands or reefs. Coastal wetlands also form when rivers deposit sediment as they reach the ocean. Plants then take root and hold the soil firm against the forces of tides and waves.

Question 28

Medmerry Case Study - Location?

Answer 28

Medmerry in West Sussex

Question 29

Medmerry Case Study - Stakeholders?

Answer 29

Local Farmers, Residents, Council, Business holders

Question 30

Medmerry Case Study - Problems?

Answer 30

Shingle ridge was ineffective and required an annual maintenance cost of £200,000 a year and yet it was ineffective as in 2008 there was a breach costing £5 million

Question 31

Medmerry Case Study - Options?

Answer 31

Hold the line, Retreat, Advance the line, Do nothing

Question 32

Medmerry Case Study - Solutions?

Answer 32

Build a 2km embankment inland with clay to protect the land behind it. Build 4 drain structures within the embankment. Placed 60 000 tonnes of rock armours at embankment edge and allowed embankment to flood during high tides

Question 33

Medmerry Case Study - Benefits?

Answer 33

The area has now a 1 in 1000 chance of coastal flooding which is the best level of protection in the UK, New flooded embankment can provide a new fishing area, Tourism increases as the area around the embankment has become a natural reserve with good viewpoints

Question 34

Medmerry Case Study - Drawbacks?

Answer 34

Habitats of existing species have been lost, loss in green farming land

Question 35

Mappleton Coast Case Study - Location?

Answer 35

Mappleton Coast

Question 36

Mappleton Coast Case Study - Stakeholders?

Answer 36

Council Farmers

Question 37

Mappleton Coast Case Study - Problems?

Answer 37

Longshore drift at the beach caused the sand to build upon the side, Erosion at the cliff face caused land loss

Question 38

Mappleton Coast Case Study - Solutions?

Answer 38

£2 million to place groynes and rock armour at the cliff

Question 39

Mappleton Coast Case Study - Benefits?

Answer 39

it was successful at preventing longshore drift and erosion in protected areas

Question 40

Mappleton Coast Case Study - Drawbacks?

Answer 40

Caused erosion up the coast in unprotected areas