The Coastal Zone Flashcards

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1
Q

Define “Fetch”

A

The distance the wave has travelled

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2
Q

What is a constructive wave?

A
  • Strong swash week backwash
  • More deposition than erosion
  • Less than 10 waves per minute
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3
Q

What is a destructive wave?

A
  • Weak swash strong backwash
  • More erosion than deposition
  • More than 12 waves a minute
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4
Q

What is Traction?

A

When larger rocks and boulders are rolled along the seabed

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5
Q

What is saltation?

A

When smaller rocks and stones a bounced in and out of current

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6
Q

What is suspension?

A

When fine particles float in the water carried by the current

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7
Q

What is solution?

A

Particles dissolved in water by acids in the sea

for example chalk or limestone

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8
Q

Four types of erosion?

A
  • Hydraulic action
  • Corrosion
  • Corrasion
  • Attrition
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9
Q

Formation of headlands and bays (3)

A
  • Harder rock and softer rock (chalk, clay)
  • Soft rock eroded more
  • Deposition in bays
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10
Q

Formation of a wave cut platform (5)

A
  1. Weakness in cliff base -> erosion
  2. = wave cut notch
  3. Overhanging cliff collapses
  4. Rock debris eroded by attrition
  5. Cliff retreats and rock pools at low tide
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11
Q

Formation of arches stacks and stumps (5)

A
  1. Weaknesses and cracks in cliff
  2. Erosion enlarges cracks into caves
  3. All round erosion of cave equals arch
  4. Base of arch eroded -> top collapses -> stack
  5. Undercutting of stack -> stump
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12
Q

Weathering

A
  • Chemical (solution) and (carbonating)
  • Mechanical
  • Biological
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13
Q

Chemical weathering (2)

A

Solution:
When rocks dissolve in rainwater

Carbonation:
Limestone and chalk dissolved by acid rain

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14
Q

Mechanical weathering (2)

A

Freeze Thaw:
Water expands when frozen

Onion Peel:
When outer layers expand and contract and weaken

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15
Q

Biological weathering

A

Tree roots or burrowing animals

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16
Q

How is a wave formed? (3)

A
  1. Wind blows over surface
  2. Friction with sea bed causes top to move faster than bottom
  3. Wave begins to break
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17
Q

Mass movement (4)

A
  • Rockfall
  • Landslide
  • Mudflow
  • Rotational Slumping (Barton on Sea)
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18
Q

Sea wall (hard)

A

A concrete barrier at the top of the beach which reflects wave energy

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19
Q

Sea wall evaluation (2,3)

A

☑Prevents erosion
☑Can help prevent coastal flooding

☒Ugly
☒Creates strong backwash
☒Expensive to build and maintain

20
Q

Groynes (hard)

A

Timber or rock built at 90 degrees to trap sediment from LSD

21
Q

Groynes evaluation (3,3)

A

☑Wider beach absorbs energy = less erosion
☑Wider beach = better tourism
☑Not too expensive (£10,000 each)

☒Starve other beaches
☒Uneven beach
☒Ugly

22
Q

Rock armour (hard)

A

Boulders at cliff base to break waves and reduce energy hitting the cliff itself

23
Q

Rock armour evaluation (3,2)

A

☑Relatively cheap (£1,000-£4,000 per metre)
☑Effective
☑Easy maintenance

☒Ugly
☒Boulders can be moved by accident

24
Q

Beach renourishment (soft)

A

Sand and shingle added from elsewhere

25
Q

Beach renourishment evaluation (4,2)

A

☑Wider beach = less energy for erosion
☑Tourism
☑Blends in
☑Quite cheap and low maintenance

☒Needs to be repeated frequently
☒Taking material from sea bed can kill organisms

26
Q

Sea wall evaluation (2,3)

A

☑Prevents erosion
☑Can help prevent coastal flooding

☒Ugly
☒Creates strong backwash
☒Expensive to build and maintain

27
Q

Groynes evaluation (3,3)

A

☑Wider beach absorbs energy = less erosion
☑Wider beach = better tourism
☑Not too expensive (£10,000 each)

☒Starve other beaches
☒Uneven beach
☒Ugly

28
Q

Rock armour evaluation (3,2)

A

☑Relatively cheap (£1,000-£4,000 per metre)
☑Effective
☑Easy maintenance

☒Ugly
☒Boulders can be moved by accident

29
Q

Beach renourishment evaluation (4,2)

A

☑Wider beach = less energy for erosion
☑Tourism
☑Blends in
☑Quite cheap and low maintenance

☒Needs to be repeated frequently
☒Taking material from sea bed can kill organisms

30
Q

Dune regeneration (soft)

A

Planting Marram grass/building fences to stabilise sand

31
Q

Dune regeneration evaluation (3,3)

A

☑Provides barrier between land and sea
☑Maintains natural coastal environment which benefits wildlife and people
☑Relatively cheap

☒Time consuming to plant Marram grass
☒People may not like not being able to go on the dunes
☒Can be damaged by storms

32
Q

Managed retreat (soft)

A

Removing defences and allowing the land behind to be flooded

33
Q

Managed retreat evaluation (2,2)

A

☑Land will become marshland (new habitat for wildlife)
☑Cheaper than maintaining hard engineering

☒People might disagree what land should be flooded
☒Normally farmland - compensation

34
Q

Factors affecting deposition (5)

A
  • High erosion rates nearby
  • In sheltered locations (eg. bays)
  • When wave energy’s reduced
  • When swash is greater than backwash
  • Where groynes are placed on the beach
35
Q

Longshore drift (4)

A
  1. Waves hit beach at an angle due to prevailing wind
  2. Sediment brought up beach at an angle
  3. Sediment drawn back at 90 degrees due to gravity
  4. Particles move across beach (until hit a groyne)
36
Q

Formation of Spits (4)

A
  1. Change in direction of shoreline
  2. LSD transports and deposits sand and shingle in a straight line out to sea
  3. Strong secondary wind can give spit a hooked end
  4. Salt marsh forms in sheltered area behind
37
Q

Formation of a bar

A

When a spit joins together two areas of land

38
Q

Formation of a bar

A

When a spit joins together two areas of land

39
Q

What is a saltmarsh

A

Low-lying coastal area that is flooded at high tide and exposed at low tide

40
Q

Saltmarsh wildlife

A

Plants:
Sea Lavender
Cordgrass

Birds:
Oystercatchers
Plovers

Insects:
Butterflies
Spiders

41
Q

Saltmarsh vegetation succession (6)

A

eg. Key Haven
1. Pioneer plants - cordgrass are salt tolerant and adapted to periodic flooding and colonise the salt marsh
2. Deposition builds to form a mudflat
3. Mudflat eventually breaks surface of water and is cleansed of salt by the rainwater
4. Clean soil = more fertile = sea lavender
5. More plants stabilise soil
6. In deeper soil, mature plants now grow (tress and shrubs)

42
Q

Causes of rising sea level (3)

A

Thermal expansion:
Greenhouse gases heat the ocean

Ice melt: ❄☔
Melted ice sheets and mountain glaciers

Topography:
Combination of ocean currents and atmospheric pressure means the ocean aren’t flat anyway

43
Q

Economic effects of rising sea level (3)

A
  • Loss of tourism
  • Potential costs of damage
  • Salt water - crops fail
44
Q

Social effects of rising sea level (4)

A
  • Death
  • Contaminated drinking water
  • Loss of housing
  • Loss of jobs in coastal sector
45
Q

Environmental effects of rising sea level (3)

A
  • Salt kills plants
  • Erosion - damage to land
  • No plants = animals suffer