Coastal landscapes and management in the uk Flashcards

1
Q

What is erosion?

A

Wearing away of the land

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2
Q

What is abrasion what does it erode?

A

CLIFFS

waves hurl pebbles against cliffs, grind down/ wearing the rock away

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3
Q

What does hydraulic action erode and what is it?

A

CLIFFS
`force of waves crash into cliffs
air trapped in cracks is compressed, breaks up rock

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4
Q

What is Solution, what does it erode?

A

CLIFFS

acids contained in sea water will dissolve some types of rock such as chalk or limestone.

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5
Q

What is attrition what does it erode?

A

BEACH MATERIAL

pebbles rolled back and forth. Collide with eachother making them smaller and rounder>eventually sand

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6
Q

When does deposition occur?

A

River deposits material when speed of flow is too low to continue carrying the load

  • lack rainfall
  • inside of meander
  • mouth, river flow vs direction of sea
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7
Q

What is deposition?

A

Dropping of material carried by river

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8
Q

Describe process of longshore drift?

A

Sediment moved along coatline
Waves approach the coast at an angle because of the direction of the prevailing wind. The swash will carry the material towards the beach at an angle. The backwash then flows back to the sea, down the slope of the beach. The process repeats itself along the coast in the zig-zag movement.

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9
Q

Describe process of longshore drift?

A

Waves transporting material driven along the
coast
1. Material brought in by waves at angle from direction of prevailing wind, swash
2. Waves retreat perpendicular to coastline due to gravity.
backwash
3. Process repeats material transported along the
coastline in zig-zag motion.

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10
Q

Compare chalk cliffs/clay and sand?

A

chalk cliffs steeper than clay and sand
• chalk cliffs have rockfall whilst clay and sand have slumping
• both are high
• both have vegetation on mass movement features
• chalk fronted by pebbles and clay with sand
• chalk have wave cut platform whilst clay has beach

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11
Q

What are waves

A

Waves form when wind blows over the sea

they erode the landcape and are a vital factor in wearing away and shaping the coast

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12
Q

What does the strength of a wave depend on?

A
  • The fetch-how far it has travelled
  • how long the wind has been blowing for
  • the strength of the wind
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13
Q

What type of waves do south westerly winds produce?

A

Large powerful waves because they have a long fetch

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14
Q

What waves will south easterly wind produce

A

Small waves bc of short fetch (british channel)

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15
Q

What are the 2 wave types?

A
  • Constructive

- destructive

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16
Q

What is the name for water that flows up the beach?

A

swash

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17
Q

The water that flows back towards the sea is known as?

A

Backwash

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18
Q

What determines wave type?

A

Energy of swash and backwash

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19
Q

Characteristics of a destructive wave?

A
  • Strong backwash and weak swash
  • stormy conditions, strong winds
  • tall with short wavelength
  • arrive quickly and have high frequency
  • strong backwash removes sediment from beach
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20
Q

Characteristics of a constructive wave?

A
  • Strong swash and weak backwash
  • occur in calm conditions not much wind
  • waves are low with long wave length and further apart
  • strong swash brings sediment up the beatch
  • weak backwash isn’t strong enough to remove sediment
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21
Q

What are exposed rocks on a coastline broken down by?

A

Weathering

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22
Q

Three main types of weathering?

A
  • Physical
  • biological
  • chemical
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23
Q

What type of weathering is freeze-thaw?

A

Physical
FREEZE-THAW ACTION:
1.rainwater enters cracks in rock
2.when temp drops (night), water freezes and expands, widens cracks
3. (Day) ice melts, more water added to larger gap
4.process repeats until crock falls off

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24
Q

What type of weathering is salt crystal growth?

A
Physical
SALT CRYSTAL GROWTH:
1. Seawater left on rock 
2.water evaporates leaving salt behind
3.slat crystals grow and exert pressure on rock 
4. Rock breaks apart
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25
Q

What type of weathering is plant root growth?

A
Biological
PLANT ROOTS:
1.plants grow on cliff top
2.roots push into cracks in rock 
3.roots grow, crack larger
4. Rock breaks away
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26
Q

What type of weathering is burrowing animals?

A

Biological
BURROWING ANIMALS:
1.small animals burrow through soil and into cracks
2.rocks broken apart

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27
Q

Example of chemical weathering?

A

CARBONATION

  1. rain/seawater enter cracks in rock
  2. Act as weak acid, dissolve carbonates in limestone/chalk
  3. Cracks get bigger
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28
Q

What is mass movement?

2 examples?

A

Downhill movement of sediment (rocks/stones) due to gravity

landslide/rockfall

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29
Q

Why do rockfalls occur?

A

Bits of rock eroded on cliff face (usually bc freezee thaw weathering)
move down slope

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30
Q

What is a landslide?

A

Large blocks of rock becoming detached and slide down hill

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31
Q

What 4 ways can beach material be moved?

A
  • Solution
  • suspension
  • saltation
  • traction
32
Q

What is solution?

A

when minerals in rocks like chalk and limestone are dissolved in sea water and then carried in solution. The load is not visible

33
Q

What is suspension

A

small particles such as silts and clays are suspended in the flow of the water.

34
Q

What is saltation

A

where small pieces of shingle or large sand grains are bounced along the sea bed

35
Q

What is traction

A

where pebbles and larger material are rolled along the sea bed

36
Q

What is deposition?

A

When the sea loses energy, it drops the material it has been carrying.
Deposition can occur on coastlines that have constructive waves.

37
Q

What factors lead to deposition by waves?

A
  • waves start to slow down and lose energy
  • shallow water
  • sheltered areas, eg bays
  • little or no wind
38
Q

What physical factors affect coastal landforms?

A
  • Geology
  • fetch of waves
  • angle of slope
  • weather conditions
  • amt. Vegetation
  • human inteference
39
Q

How does rocktype affect coastlines?

A

Geology

Hard rock types are less likely to erode

40
Q

How does wind strength and fetch affect coastlines?

A

The fetch of the wave and the strength of the wind. Powerful winds and a long fetch create the most damaging (erosive) waves.

41
Q

How does angle of slope affect coastlines?

A

steep slopes erode more violently and frequently

42
Q

How does the amount of vegetation affect coastlines?

A

the presence of vegetation helps stabilise slopes but also increases the occurrence of biological weathering

43
Q

How does human inteference affect coastlines?

A

no man-made structures (eg sea walls) to protect the coast, then the coast is more vulnerable to attack. However, the construction of houses, industry and other man-made structures in the first instance are the reasons why coastal erosion is a concern

44
Q

Geology of the east coast of the uk?

A

The east coast of the UK has mainly ‘younger’ softer rock types which are more vulnerable to attack by waves

45
Q

When do headlands and bays form?

A

When a stretch of coastline is formed from different types of rock

46
Q

How do bays and hedlands form?

A

Discordant coastlines
Bands soft rock weaker, eroded quickly. forms bays.
(A bay is an inlet of the sea where the land curves inwards, usually with a beach. )
Hard rock more resistant to erosion.
softer rock is eroded inwards, hard rock sticks into the sea, forming a headland

47
Q

Where are wavecut platforms and cliffs found?

A

headlands, since they are more open to the waves

48
Q

Where are beaches likely to be found?

A

Bays are more sheltered with constructive waves which deposit sediment to form a beach.

49
Q

How are sloping vs steep cliffs formed?

A

Soft rock erodes quickly and forms gentle sloping cliffs, whereas hard rock is more resistant and forms steep cliffs

50
Q

How are wavecut platforms formed?

What two small scale lanforms also form?

A
  1. Sea attacks base of cliff (between high and low water mark)
  2. Wave cut notch (small scale landform) is formed by erosional processes such as abrasion and hydraulic action
  3. As notch increases in size, cliff becomes more unstable, collapses, leading to retreat o cliff face
  4. Backwash carries eroded material away leaving wavecut platform
  5. Process repeats. Cliff continues to retreat
  6. Rockpools (small scale landforms) are left which often home wide range marine life and attract tourists
51
Q

What is a wavecut platform

A

Wide gently sloping rocky surface found at base of cliff

52
Q

What erosional features are found in a headland?

A

Caves, arches, stacks, stumps

53
Q

How are waves,arches,cracks, stumps formed?

A
  1. Cracks formed in headland through erosional processes hydraulic action+abrasion
  2. waves erode cracks, opens to form cave
  3. cave becomes larger (erosion) eventually bracks through headland forming arch
  4. base of arch widened by erosion until roof is too heavy and collapses, leaving a stack (isolated column of rock)
  5. This stack is undercut at the base until it collapses, forming a stump
54
Q

What happens when water loses energy?

A

When water loses its energy, any sediment it is carrying is deposited.

55
Q

How are beaches formed?

A

Made of Eroded material transported and deposited

to occur waves must have limited energy
often formed in sheltered areas like bays
constructive ways build up beaches bc have strong swash and weak backwash

56
Q

Where are sandy beaches usually found?

Where are pebble beaches often found?

A

Sandy beaches are usually found in bays where the water is shallow and the waves have less energy.

Pebble beaches often form where cliffs are being eroded, and where there are higher-energy waves.

57
Q

How does material size change on a beach?

A

The size of the material is larger at the top of the beach, due to the high-energy storm waves carrying large sediment. The smallest material is found nearest the water as the waves break here and break down the rock through attrition.

58
Q

What are spits?

A

extended stretch of sand or shingle jutting out into the sea from the land. Spits occur when there is a change in the shape of the landscape or there is a river mouth or estuary.

59
Q

How are spits formed?
How is a hooked end formed?
Where are salt marshes/mud flats formed?

A
  1. sediment carried by longshore drift
  2. change in shape of coastline, deposition occurs
  3. Long thin ridge of material is deposited=spit
  4. change in wind direction, hooked end
  5. waves can’t get past spit so water behind spit is v sheltered, silts deposited here forming salt masrhes or mud flats
60
Q

Example of a spit?

A

Spurn point, holderness coastline, eastcoast uk in yorkshire

61
Q

What are concordant coastline?

What sort of shapes are they?

A

Concordant:
rocks layers are formed parallel to the sea so erosion rates along the coastline are ecen.
Few/no headlands and bays

62
Q

What are discordant coastlines?

What landforms do they cause?

A

Discordant:
rocks bands are perpendicular (right angles) to the sea so erosion rates vary along the coastline depending on rock type.
Less resistenat erodes faster-bays
more resistant juts out forming headlands

63
Q

What forms on wavecut platforms?

A

Rock pools-unique ecosystems

64
Q

Coastal case study location?

A

Holderness coastline, east coast of England in yorkshire

65
Q

Main fact about holderness?

A

fastest eroding coastline in Europe, receding 2 meters a year

66
Q

Why is holderness receding so quickly? simple

A

Retreats 2m/year:

  • erosion
  • geology
  • climate
  • groynes
67
Q

Why is holderness eroding so quickly? explain

A

Retreats 2m/year:

  • erosion, strong prevailing winds, long shore drift moves material south down coast,
  • geology, soft boulder clay cliffs erode quickly, especially when saturated during storms
  • climate, increased threat sea-level rise due to climate change
  • groynes, at mappleton protect town but have increased erosion to the south as beaches are starved of material, susceptible to destructive waves
68
Q

Management stategies on holderness coastline?

A
  • Bridlington is protected by a 4.7 km long sea wall.
  • Hornsea is protected by a sea wall, groynes and rock armour.
  • Coastal management at Withersea has tried to make the beach wider by using groynes, and also uses a seawall to protect the coast.
  • Mappleton is protected by rock groynes.
  • Spurn Head is protected with groynes and rock armour.
69
Q

Disadvantages of management stategies at holderness?

A
  • There has been an increase in erosion at Great Cowden because of the groynes used in Mappleton. This has led to farms being destroyed by the erosion and the loss of 100 chalets at the Golden Sands Holiday Park.
  • Some people disagree with where the sea defences are located, especially if it means the land in their community is not protected.
  • Some sea defences negatively impact tourism and reduce the amount of money coming in to the area.
70
Q

Coastal management stategies?

A
  • Sea wall
  • marsh creation (managed retreat)
  • beach nourishment
  • rock armour
  • dune regeneration
  • groynes
71
Q

What are the two types of coastal management strategies?

A

Hard engineering:
Hard engineering involves building artificial structures which try to control natural processes

soft engineering:
Soft engineering does not involve building artificial structures, but takes a more sustainable and natural approach to managing the coast

72
Q

What is a sea wall?
Where are they placed?
+/-

A

Sea wall:

  • hard engineering
  • concrete/rock barrier to the sea, 3-5m high
  • foot of the cliffs/ top of the beach
  • curved face reflects wave back into sea

+Effective protecting base of the cliff/ are behind
+Sea walls usually have promenades so people can walk along them.

  • expensive
  • ugly, less attractive to tourists
  • Waves are still powerful and can break down and erode the sea wall
73
Q

Alternative name for marsh creation?
Type of engineering?
What does it involve?
+/-

A

[managed retreat]

  • soft engineering
  • allowing low-lying coastal areas to be flooded by sea, become salt marshes

+salt marshes provide new habitat, diversify ecosystem
+low cost

-compensation for loss of buildings and farmland

74
Q

What is beach nourishment?
Type of engineering/
+/-

A

Beach nourishment:

  • soft engineering
  • addition sand/shingle to existing beach to make it higher

+Blends in with the existing beach.
+Larger beaches appeal to tourists.

  • Needs to be constantly replaced.
  • The sand has to be brought in from elsewhere
75
Q

What is rock armour?
Type of engineering?
+/-

A

Rock armour:

  • hard engineering
  • piles large boulders at foot of cliff, rocks force waves to break, absorb their energy, protect the cliff

+Cheaper than a sea wall and easy to maintain.
+Can be used for fishing.

  • They look different to the local geology, as the rock has been imported from other areas, unattractive
  • The rocks are expensive to transport.
76
Q

What are groynes?
Type of engineering?
+/-

A

Groynes:

  • hard engineering
  • Wooden or rock structures built out at right angles into the sea

+Builds a beach - which encourages tourism.
+They trap sediment being carried by longshore drift.

  • By trapping sediment it starves beaches further down the coastline, increasing rates of erosion elsewhere.
  • They look unattractive.
77
Q

What is dune regeneration?
Type of engineering?
+/-

A

Dune regeneration:
-adding sand or planting Marram grass on sand dunes stabilises the dunes and helps to trap sand to build them up.

+Relatively cheap.
+Maintains a natural-looking coastline

  • can be damaged by storm waves
  • regular maintenance