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Coasts Flashcards

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1
Q

Three types of system

A

Closed
open
Isolated.

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2
Q

What is a isolated system?

A

Neither mass nor energy can enter.

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3
Q

What is an open system?

A

One where both mass and energy can enter.

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4
Q

What is a closed system?

A

One where energy can enter but not mass.

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5
Q

What is an element?

A

A feature of a system.

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6
Q

What is an attribute?

A

A characteristic of a system.

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7
Q

What is a store?

A

Places where elements are kept before moving on to another store.

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8
Q

What are relationships?

A

How elements are interconnected.

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9
Q

What are boundaries?

A

Places that prevent an element from moving to another system.

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10
Q

what are Inputs?

A

Elements that put energy into a system.

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11
Q

What is an output?

A

Elements that cause energy to leave a system or elements that are a product of a system.

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12
Q

What are the four major subsystems of earth?

A

Atmosphere
Lithosphere
Biosphere
Hydrosphere.

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13
Q

What is dynamic equilibrium?

A

When a system is in balance in a constantly changing system.

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14
Q

What is negative feedback?

A

When elements within a system are reduced and equilibrium can be maintained, the system stays in equilibrium.

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15
Q

What is positive feedback?

A

When inputs in a system continue to increase upsetting the equilibrium.

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16
Q

What is a landform?

A

A singular feature on a coastline.

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17
Q

What is a Landscape?

A

The coastline or sediment cell as a whole.

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18
Q

What are the four shores that make up the littoral zone?

A

Offshore
Nearshore
Backshore + on
shore = (beach shore).

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19
Q

What are the four inputs (sources of energy) on a coast?

A

Wind
Tides
Currents
Waves.

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20
Q

What is a fetch?

A

The distance travelled by wind or waves across open water, uninterrupted by land.

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21
Q

What is an ocean gyre?

A

Wind patterns that are circular, they can change waves and create currents.

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22
Q

What places have a high fetch and consequently have a high wave energy?

A

South west England and Wales
Chile
Western USA
South Western Australlia.

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23
Q

What direction is the prevailing wind in the UK?

A

South westerly prevailing wind moving to the North East.

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24
Q

What 3 factors affect wave energy?

A

The strength of the wind (which is determined by the pressure gradient)
The direction of the wind
The fetch.

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25
Q

How is wind moved/created?

A

Wind moves from areas of high pressure to a low pressure.

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26
Q

How are waves formed?

A

As air moves across the water, frictional drag disturbs the surface water, forming ripples this begins to create an orbital motion of water particles - as the water nears the coast and more energy is built horizontal movement of water occurs as waves are driven onshore to the beach.

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27
Q

What are the two types of tide?

A

Spring tide

Neap tide.

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28
Q

Which tide results in the biggest waves / greatest energy (Tidal range)?

A

Spring tides.

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29
Q

What happens regarding the Sun, moon and the earth during a Spring tide?

A

During a spring tide, the sun and moon are in alignment and as a result the strength of gravity from both the sun and moon that are both in line works together to create a larger tidal range (there is a bigger high tide and smaller low tide).

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30
Q

What happens regarding the Sun, moon and the earth during a neap tide?

A

In a neap tide, the moon is at a right angle to the sun, so the gravitational pull of the celestial bodies act against each other to create a smaller tidal range (low tides aren’t that low and high tides aren’t that high)

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31
Q

How do Spring tides and neap tides affect wave energy?

A

A greater tidal range caused by a spring tide, tidal currents will be greater and have greater energy, this affects the amount of transpiration, erosion as well as the height and length of the waves.

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32
Q

At what times throughout a month (30 day cycle) do spring and neap tides occur?

A

Day 1: Sun and moon in line to create spring tide
Day 7 and a half: Sun and moon are 90 degrees out of place creating a neap tide
Day 15: Spring tide occurs when moon is behind earth and sun is in front
Day 22 and a half: sun and moon become 90 degrees out of place again creating a neap tide
Day 30: Same as day 1.

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33
Q

What is a Rip current and how do they form?

A

Rip currents are powerful underwater currents occurring in areas close to the shoreline on some
beaches when plunging waves cause a build-up of water at the top of the beach
The backwash is forced under the surface due to resistance from breaking waves , forming an underwater current
This flows away from the shore more quickly due to beach features, such as a gap in a
sandbar, creating a rip current.

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34
Q

Describe briefly the beach cross section?

A

Breaker zone ->
Surf zone ->
Swash zone (and foreshore) ->
Backshore (sometimes containing berms).

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35
Q

What are the key features of constructive waves?

A 
Strong swash 
Weak backwash 
More deposition than erosion 
Low height (under a meter) 
Long length
Low frequency 6 - 9 per minute 
Low energy
Creates gently sloped beaches.
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36
Q

What are the key features of a destructive wave?

A 
Weak swash 
strong backwash 
Main process is erosion 
High wave height (more than a meter) 
Short length 
High frequency 11 - 16 per minute 
High energy
Creates steeply sloped beaches.
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37
Q

What factors may affect what type of wave is present on a coastline?

A

In summer, constructive waves dominate but destructive waves dominate in winter
Constructive waves may become destructive waves if a storm begins
Climate change may increase the storm frequency within the UK
Coastal management may affect the type of waves that occur.

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38
Q

Example of a feedback loop involving constructive and destructive waves?

A

The presence of constructive waves causes deposition on the beach, which in turn leads to the
beach profile becoming steeper
Steeper beaches favour the formation of destructive waves which are then more likely to occur
The destructive waves erode the beach , reducing the beach
profile and leading to the formation of constructive waves
As constructive waves occur more frequently in summer when there are fewer storms, this means that the beach profile is more gentle in summer and steeper during the winter months when destructive waves are more common
This should lead to a state of dynamic equilibrium though in reality this may not occur due to external factors such as the wind strength and direction.

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39
Q

Outline what coasts of high energy are like?

A

Stretches of the Atlantic coast see high energy where the rate of erosion exceeds the rate of deposition, as a result erosional landforms are found in these environments.

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40
Q

Outline what coasts of Low energy are like?

A

These tend to be sandy and estuarine, here the rate of deposition exceeds the rate of erosion, and as a result depositional landforms like beaches, spits and costal plains tend to be found there.

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41
Q

Where does the oceans sediment come from (what are the sand sources)?

A

Rivers and estuaries
Cliff erosion
Offshore sand Bank
Biological material

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42
Q

What are littoral cells?

A

All coasts are divided into natural components called littoral cells (a sub section of the 11 major UK sediment cells)
Each cell contains a complete cycle of sedimentation

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43
Q

What is the littoral Budget?

A

A costal management tool used to analyse and describe the different sediment inputs and outputs on the coast and is used to predict morphological changes in a coast over time, it is the balance between inputs and outputs of sediment on a stretch of coastline.

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44
Q

Example of a negative feedback loop on the coast regarding the littoral budget?

A

Beach erodes during storm that is in equilibrium
Sediment forms an offshore bar forcing waves to break over it early,
Waves lose energy and dissipate sooner, reducing erosion
When storm calms the bar is slowly reworked back into the beach.

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45
Q

Example of a positive feedback loop regarding the littoral budget?

A

Storm breaches a beach that is not in equilibrium
A vulnerable area is formed
Beach becomes susceptible to blowout and vegetation is removed from beach
More erosion occurs because there is less vegetation and more and more vegetation is removed as vegetation becomes more sparse.

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46
Q

What are all the High energy coasts landforms?

A 
Cliff retreat 
Headlands 
Bays 
Cliffs 
Arches 
Stacks 
Stumps 
Wave cut notches 
Wave cut platforms.
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47
Q

What are all the landforms found in landscapes of low energy?

A 
Cusps 
Barrier islands 
Drift aligned beaches 
Sand dunes
Beaches 
Tombolo's 
Spits 
Bars 
Barrier beaches.
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48
Q

What are the factors affecting the rate of erosion?

A 
The weather 
The type of erosion 
Type of rock (Googology) 
Weathering and its extent 
Arrangement of the rock (the lithology).
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49
Q

How does the weather and type of erosion affect the rate of erosion?

A

Hydraulic action and abrasion/corrasion are the most significant types of erosion and bothy of these are exacerbated in storm conditions.

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50
Q

How does the type of Rock (Geology) affect the rate of erosion?

A

Hard rocks like granite resist erosion much longer than softer sediments like chalk or limestone.

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51
Q

How does the Lithology of rock affect the rate of erosion?

A

Lithology can include the layering of rock both horizontally and vertically, discordant and concordant, if soft rock is in front of the hard rock it will erode quicker.

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52
Q

What is tidal scour?

A

When the sediment in waves erodes and scours rock along the tide.

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53
Q

What are marine processes?

A

process occurring on, or due to the effect of, the sea.

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54
Q

What are the three main marine processes?

A

Marine erosion
Marine transportation
Marine and aeolian deposition.

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55
Q

What are the main types of marine erosion?

A 
hydraulic action;
 Wave quarrying;
 abrasion/corrasion; 
attrition;
contribution of solution/corrosion
cavitation.
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56
Q

What is hydraulic action and how does it work?

A

Hydraulic action = A form of erosion in which air becomes trapped and compressed in joints in the rock or between the breaking wave and the cliff
The high pressure causes the cracks to force apart and widen when the wave retreats and the air expands. Over time this causes the rock to fracture
At the same time bubbles found within the water may implode under the high pressure creating tiny jets of water that over time erode the rock
This erosive process is cavitation.

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57
Q

What can hydraulic action form?

A
  • wave cut notches/platforms
  • cracks, caves, arches, stack, stumps
  • bays and headlands
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58
Q

How is Hydraulic action linked to the sources of energy?

A
  • when winds are higher, waves have more energy and therefore increasing the rate of hydraulic action
  • When the tide comes in (high tide) waves have more energy and the speed of erosion by hydraulic action will be increased.
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59
Q

What is wave quarrying and how does it work?

A

high energy, tall waves hitting the cliff face have the power to enlarge joints and remove large chunks of unconsolidated rock from a cliff in one go, acting like a large digger on the cliff face.

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60
Q

What can wave quarrying lead to?

A
  • wave cut notches/platforms
  • cracks, caves, arches, stack, stumps
  • bays and headlands.
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61
Q

how is Wave quarrying linked to the sources of energy?

A
  • when winds are higher, waves have more energy and therefore waves have greater energy increasing the rate of hydraulic action
  • When the tide comes in (high tide) waves have more energy and the speed of erosion by hydraulic action will be increased.
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62
Q

What is abrasion and how does it work?

A

the process where sediment is moved along the shoreline, causing it to be worn down over time, creating round and smooth surfaces over time.

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63
Q

what can abrasion lead to?

A

• wave cut notches/platforms

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64
Q

What is corrasion and how does it work?

A

When tides move in, they pick up bits of sediment from the seabed (a temporary sediment store/sink hurled against the cliffs at high tide, causing the cliffs to be eroded
The shape, size, weight and quantity of sediment picked up, as well as the wave speed, affect the erosive power of this process.

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65
Q

What can corrasion lead to?

A
  • wave cut notches/platforms
  • cracks, caves, arches, stack, stumps
  • bays and headlands
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66
Q

What is attrition and how does it work?

A

Wave action cause rocks and pebbles to hit against each other, wearing each other down and so becoming round and eventually smaller. Attrition is an erosive process within the coastal environment, but has little to no effect on erosion of the coastline itself.

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67
Q

What is solution / corrosion?

A

The mildly acidic seawater can cause alkaline rock such as limestone to be eroded and is very similar to the process of carbonation weathering
This is a potential link between the carbon cycle, because as global warming leads to increased sea water acidity, the rates of corrosion related erosion could increase.

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68
Q

What are the four types of marine transportation?

A

Traction
Saltation
Suspension
solution?

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69
Q

What is traction?

A

Large, heavy sediment rolls along the sea bed pushed by currents.

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70
Q

What is saltation?

A

Smaller sediment bounces along the sea bed, being pushed by currents.

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71
Q

What is suspension?

A

Small sediment is carried within the flow of the water.

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72
Q

What is solution?

A

Dissolved material is carried within the water.

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73
Q

Describe the process of longshore / littoral drift?

A

Waves hit the beach at an angle in the direction of the prevailing wind (south westerly winds in the UK). The waves push sediment in this direction and up the beach in the swash
Due to gravity, the wave then carries sediment back down the beach in the backwash at a 90 degree angle. This pushes sediment along the beach over time in a zig zag motion.

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74
Q

Describe the process of deposition?

A

Deposition occurs when sediment becomes too heavy for the water to carry, or if the wave loses energy
High-energy coastlines continue to transport smaller sediment, so larger rocks and shingle are deposited in these environments
Low-energy coastlines have much smaller sediment, which is only deposited in these areas where there is a much lower water velocity. Deposition includes gravity settling and flocculation.

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75
Q

What is gravity setting?

A

A type of deposition in which the waters velocity decreases and subsequently sediment is deposited.

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76
Q

What is flocculation?

A

This is an important process in salt and tidal marshes

Clay particles clump together due to chemical attraction and then sink due to their high density.

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77
Q

What is Aeolian deposition?

A

Deposition that occurs as a result of the wind on the surface of the earth.

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78
Q

What is marine deposition?

A

Deposition that occurs due to any sea related processes.

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79
Q

What are sub aerial processes?

A

Processes occurring the open air or on the earth’s surface, including mass movement and weathering.

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80
Q

What are the three types of sub aerial weathering?

A

Biological
Physical/mechanical
Chemical.

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81
Q

What is weathering?

A

the breakdown or disintegration of rock in situ, leading to the transfer or sediment into the littoral zone, acting as an input most of the time.

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82
Q

What is mechanical / physical weathering?

A

any weathering that does not involve any chemical changes.

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83
Q

What are the three types of physical/ mechanical weathering?

A

Salt crystallisation
Freeze thaw
Wetting and drying

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84
Q

What is freeze thaw and how does it work?

A

When water enters a crack in a fault due to rain, it freezes in cold weather, when this happens it expands in volume by about 10%
The expansion exerts pressure on the rock, causing the crack to widen
With continuous freeze thaw, fragments of rock break away over time, collecting at the bottom of the cliff as scree
The fragments created here can often be used in costal processes to further increase erosion. For example in 2001, following a cold winter the south coast of England saw serious cliff falls from freeze thaw, mainly affecting porous rocks like chalk at the white cliffs of dover.

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85
Q

What is salt crystallisation and how does it work?

A

When saltwater evaporates, it leaves crystals behind. These grow over time and exert stress onto the rock, similarly to ice
The salt can also corrode some rocks, particularly if they contain a high amount of iron.

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86
Q

What is wetting and drying and how does it work?

A

Rocks undergo series of wetting and drying phases, and many rocks that are high in clay (such as shale) expand when they get wet and contract when they get dry, this can cause them to crack and break up.

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87
Q

What is biological weathering?

A

the breakdown of rocks that comes as a result of organic activity.

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88
Q

What are the five types of biological weathering?

A 
Plant roots 
birds 
rock boring 
seaweed acids 
decaying vegetation.
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89
Q

How is plant roots a form of weathering?

A

Roots of plants growing into the cracks of rocks, which exerts pressure,
Eventually splitting the rocks

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89
Q

How are birds a form of weathering?

A

Some birds such as Puffins dig burrows into cliffs weakening them.

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90
Q

How is rock boring a form of weathering?

A

Many species of clams secrete chemicals that dissolve rocks

many animals also burrow into the ground to make nests

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91
Q

How is seaweed acids a form of weathering?

A

Kelp contains sulphuric acid, which dissolves rock minerals.

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92
Q

How is decaying vegetation a form of weathering?

A

Water flows through decaying plants and becomes acidic.

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93
Q

What is chemical weathering?

A

Weathering that involves a chemical reaction or chemical change.

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94
Q

What are the three types of chemical weathering?

A

Carbonation
Oxidation
Solution.

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95
Q

Explain how carbonation works?

A

Rainwater absorbs CO2 from the air to create a weak carbonic acid rain reacts with limestone to form calcium bicarbonate, which is then easily dissolved allowing erosion

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96
Q

Explain how carbonation works?

A

Rainwater absorbs CO2 from the air to create a weak carbonic acid rain reacts with limestone to form calcium bicarbonate, which is then easily dissolved allowing erosion
The cooler the temperature, the more carbon dioxide rainwater absorbs, making carbonation more effective in winter.

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97
Q

How does oxidation work

A

The reaction of rock materials with oxygen, when exposed to air, some rocks will become oxidised which in turn increase its volume causing the rock to crack
Most common with iron minerals

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98
Q

How does solution work as a form of weathering?

A

When rock minerals like rock salt (halite) is dissolved.

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99
Q

What is mass movement?

A

movement of material down a slope under the influence of gravity

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100
Q

What are the seven main types of mass movement?

A
  • Soil creep
  • Mudflow
  • Landslide
  • Rock fall
  • Slumping/rotational slip/landslip
  • Runoff
  • Soilfluction.
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101
Q

What is soil creep?

A

a slow form of movement of soil particles downhill, it involves soil particles rising to the surface during wetting or freezing (moving downhill) and then returning back into the surface when it is wetted or frozen once again
Soil creep forms shallow terracettes and can be seen occurring through the build-up of soil on walls and the bending of tree trunks (Terracettes = a ridge on a hillside, like the ones at white horses).

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102
Q

What is a mudflow?

A

An increase in the water content of soil can reduce friction, leading to earth and mud to flow over underlying bedrock , or slippery materials such as clay
Mudflows represent a serious threat to life as they can be very fast flowing
Water gets trapped within the rock, increasing pore water pressure, which in turn forces water particles apart and leads to slope failure.

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103
Q

What are landslides?

A

Heavy rainfall can reduce friction in cliffs and lead to a landslide
It occurs when a block of intact rock moves down the cliff face very quickly along a planar surface (a slide plane) unlike mudflows the moving block of material stays intact and can lead to the build-up` of scree toward the bottom of a slope.

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104
Q

What are Rockfalls?

A

It involves the sudden breaking away of rock fragments at a cliff face
It usually occurs on steep cliffs made of resistant rock and often comes as a result of mechanical weathering (mainly freeze thaw weathering) or an earthquake
Once broken away the rocks form scree at the bottom of the coast, acting as a temporary store at a costal system.

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105
Q

What is slumping/ rotational slip / landslip?

A

occurs on surfaces that are curved rather than flat or steep
They commonly occur on areas of weak clays or sands, often when permeable rocks overtop impermeable rock which causes a build-up of pore water pressure
The land collapses under its own weight, due to increased PWP (Pore water pressure)
This creates a terraced appearance.

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106
Q

What is runoff?

A

when overland flow occurs down a slope or cliff face, small particles are moved downslope into the littoral zone, potentially creating an input into the sediment cell
Runoff can also be responsible for increasing pollution in coastal areas.

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107
Q

What is soilfluction?

A

Soilfluction is specific to cold, periglacial environments, where, in the summer the surface layer of the soil thaws out, becoming extremely saturated as the permafrost beneath it cannot be infiltrated
As a result the active layer (sodden surface layer) is moved slowly downhill as a result of heave and flow
This process can lead to the formation of Soilfluction lobes.

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108
Q

How does temperature and climate affect what type of weathering is occurring ?

A

Temperature and climate can influence the prominence of weathering
In colder climates, mechanical weathering is more common, whereas in warmer climates, chemical weathering is more common.

109
Q

What phrase can be used to remember the differences between Eustatic and Isostatic sea level change?

A

There is more of U (Eustatic) than than there is of I (Isotatic)

110
Q

What is Eustatic Sea level rise?

A

Sea level change that occurs globally, coming as a result of changes in the shape of the ocean basin, changes in the volume of water or the size of water itself.

111
Q

Is Eustatic sea level change local or global?

A

Global.

112
Q

What are the three main ways Eustatic sea level change can occur?

A

Due to increased volumes of water as a result of accumulation of water in ice or the release of it during an interglacial period
Increases in temperature outside cause thermal expansion, which increases the size of water particles themselves (particles move around faster and exert more pressure within the water
If there is tectonic uplift in the oceans the capacity of the worlds ocean basins will increase or decrease.

113
Q

What is isostatic sea level change?

A

Isostatic sea level change is always local and comes as a result of land rising and falling - rather than the sea.

114
Q

Is Isostatic sea level change local or global?

A

Local

115
Q

What are the two main ways isostatic sea level change can occur?

A

Isostatic sea level change could be due to post-glacial adjustment glaciers weigh down the land
beneath known as glacial compression, when the ice melts the land slowly rises back upwards over a long period of time known as post glacial or isostatic rebound
For example, post-glacial adjustment for the UK
after the Ice Age has caused Southern England to subside around 1mm per year and Scotland to
rebound and increase around 1.55mm per year

Tectonic activity (such as earthquakes and volcanic eruptions) may cause land subsidence,
therefore causing isostatic sea level increase. Landslides and avalanches can also cause additional sediment to enter a costal system, adding sediment to the sea floor.
116
Q

What is the case study on Isostatic sea level change due to tectonic activity?

A

2004 Boxing day Tsunami.

117
Q

What are the key facts of the 2004 Boxing day Tsunami?

A

On December 26 2004, a magnitude 9.0-9.3 occurred in the Indian ocean
Epicentre was west of northern Sumatra, Indonesia
300,000 people died
Part of the earths crust by the city of banda aceh sunk permanently flooding parts of it.

118
Q

How did the 2004 Indian ocean Earthquake cause isostatic sea level rise?

A

caused 1600km of fault line to slip 15m along the subduction zone of the burma plate
30km3 of water was displaced, causing the Tsunami
Realised the seabed of the Indian ocean causing a global sea level rise increase of 0.01 mm
Tectonic uplift by the epicentre in Sumatra caused the seabed to rise several meters, causing the city of Banda Aceh and other nearby places to flood.

119
Q

How much has the sea level risen since the last glacial maximum(and how long ago was that)?

A

The sea level has risen by about 130m since the last glacial maximum 21,000 years ago

120
Q

When did sea level rise begin to plateu at roughly where it is today?

A

Sea level plateaued around 7,000 years ago only increasing very slowly, only rising by about 4m to where it is today.

121
Q

What are emergent coastal landscapes?

A

a coast where landforms have been revealed due to falling sea levels (the landforms are merging out of the water).

122
Q

What are the main emergent coastal landforms?

A

Wave beaches
Former wave cut platforms
relic cliffs, stacks and arches.

123
Q

Where can coastlines of emergence be found in the UK?

A

In the North where post glacial rebound has meant sea level has fallen leading to relic features emerging out of the sea
Particularly on the Scottish Isle of Arran on the west coast of Scotland.

124
Q

What are submergent coastal landscapes?

A

Coastlines of submergence as a result of flooding in the area (landforms are submerged underwater) mostly due to Eustatic (but sometimes isostatic) sea level change where land is submerged underwater.

125
Q

What are the 3 types of submergent coastal landscapes?

A

Rias
Fjords
Dalmatian coasts

126
Q

What are rias?

A

A river valley that is v shaped that has become flooded due to sea level rise on the coast, these are predominantly found in south west England.

127
Q

What is an example of a Rias and some details?

A

The Kingsbridge estuary In south Hams, Devon which is 8.6km in length where the town of Salcombe has been built.

128
Q

What is a Fjord?

A

A submerged U shaped valley that are formed when deep glacial troughs that are long and steep sided are flooded, Fjords tend to be much deeper inland than Rias,
They are found in Norway, Chile and new Zealand.

129
Q

What is an example of a Fjord?

A

Milford sound in the south west of New Zealand’s south island, the highest mountain Mitre peak is 1683m tall and the Fjord has a depth of 291m

130
Q

What are Dalmatian coasts?

A

Occur when ridges and valleys that run parallel to the coast are submerged due to sea level rise that create a series of offshore islands that runs parallel to the coast.

131
Q

What is unique about Dalmatian coasts?

A

They are only found in Croatia in Dalmatia, from which they derive their name from.

132
Q

What is an example of a relic beach?

A

Kings cave beach on the Isle of Arran on the west coast of Scotland near the village of blackwater foot
The raised beach is 8m high and formed around 6,000 years ago

133
Q

What is an example of a relic stack?

A

The old man of Hoy on the Orkney islands, found in rackwick bay. It is 449ft high, 137m

134
Q

According to the IPCC (international panel for climate change) When did sea level rise stabilise?

A

Around 3,000 years ago.

135
Q

What was the average sea level rise during 1900 - 1990 compared to 1993 to 2000?

A

Between 1900 and 1990 studies show that sea level rose between 1.2 millimeters and 1.7
1993-2000 average yearly sea level rise was around 3.2 mm

136
Q

How much did temperatures rise from 1990 and 2010?

A

Around 0.85%

137
Q

What is the Case study for the impact of climate change and rising sea levels?

A

Kiribati

138
Q

How much will sea level rise by 2100?

A

Anywhere from 30cm to 1m varying from place to place.

139
Q

How much do melting glaciers and thermal expansion contribute to sea level rise?

A

45% associated with melting glaciers (21% glacier, 16% Greenland, 8% Antarctica)
38% associated with thermal expansion.

140
Q

Where is Kiribati located?+

A

It is located at the point where the international date line and equator meet, it is a pacific island nation far east of the Solomon islands.

141
Q

What are the Characteristics of Kiribati (why is it vulnerable to climate change)?

A

It is made up of 33 low lying islands, with low lying sand and mangrove atolls making up lots of the islands,
Most islands are less than a metre above sea level with many of its islands at risk of disappearing in the next fifty years.
average elevation of 2m

142
Q

How much has the sea level risen by in Kiribati?

A

1.2 cm, more than 4 x the global average.

143
Q

What are the impacts of rising sea level in Kiribati?

A
  • President Anote Tong was forced to purchase 20km2 of land from the nearby Fiji
  • the rising sea level contaminated the ground water (salinization) affecting its ability to grow crops and freshwater drinking sources (created a positive feedback cycle with the mangroves which were protecting them from flooding
  • The land purchased from Fiji will be used for agricultural and fishing practices to supply the nations dwindling food supplies
  • The government has launched a ‘migration with dignity scheme’ with residents being given the choice to migrate to nearby countries like NZ
  • If the islands become fully submerged Kiribati’s population will become some of the first environmental refugees.
144
Q

How much has the sea level risen by since the industrial revolution?

A

Since 1880 and the industrial revolution, sea levels have increased by around 2.35 meters.

145
Q

What are the two main ways to measure sea level change?

A

Sea level is measured by two main methods: tide gauges and satellite altimeters.

146
Q

How do tide gauges measure sea level?

A

Tide gauge stations from around the world have measured the daily high and low tides for more than a century, using a variety of manual and automatic sensors
Using data from scores of stations around the world, scientists can calculate a global average and adjust it for seasonal differences.

147
Q

How do satellite altimeters measure sea level change?

A

Satellite altimeters measure the ocean surface height (sea level) by measuring the time it takes a radar pulse to make a round-trip from the satellite to the sea surface and back
This data can act as proof of sea level rise.

148
Q

Why do sea level rise predictions vary from place to place?

A
  • Sea level rise depends on human activity, it is reliant on how much co2 and other greenhouse gasses are released into the atmosphere, and that in itself is currently uncertain
  • The climate is highly complex and it is not certain how much of an effect more climate change will cause as well as the significance of many positive feedback loops on the speed at which sea level rise occurs
  • As the technology improves and sea level rise is understood, sea level rise forecasts become more accurate and will change over time based on human GHG emissions
  • Sea level rise is different in many parts of the world, so different groups may be using data from different locations that will all experience a different level of sea rise, due to local – isostatic – sea level rise factors.
149
Q

Where are sea levels expected rise the most?

A

: In Europe the sea level is expected to rise the most in the Mediterranean, specifically the North African and Turkish coast – here it is expected to rise by around 5-10mm per year compared to the rest of the continent which should see sea level rise by around 2mm per year
The greatest sea level rise is likely to occur in the south China sea around Indonesia, Malaysia and other nearby countries like Thailand
Here sea level could rise by more than 20mm a year which would have devastating impacts on the costal agricultural plains in the region
Much of the South Asian coast as well is believed to see sea level rise of 5-10mm per year, all the way from the Pakistan coast to North Korea and the North of Japan
All parts of Southern Mainland Asia will see a rise like this with the exception of the area around Laos, Cambodia, Thailand and Vietnam which will see sea levels increased by more than 20mm a year
This could have massive ramifications as it’s believed 157 million people here live below 2m above sea level it is also a highly important agriculturally intensive land, that is crucial for the worlds food supply.

150
Q

Why are Sea levels rising fastest in SE Asia?

A

This Rapid rise is associated to (according to the IPCC) the fact that the Indian ocean is warming faster than any other ocean, this means that thermal expansion is occurring there at a rate greater than anywhere else and subsequently the sea is rising fastest
The sunda shelf in south East Asia (Sundaland is a term for the region of South-eastern Asia which encompasses these areas of the Asian continental shelf that were exposed during the last ice age) is another reason for rapid sea level rise in south East Asia
The sea above the Sunda shelf is warm due to its shallow depth and position along the equator and as a result thermal expansion has caused sea levels there to rise faster than anywhere else.

151
Q

What causes of sea level rises can be mitigated and what cannot?

A

The both thermal expansion and the melting of glaciers can be mitigated to an extent if Humans cut back on Carbon emissions so the greenhouse effect creates less of an impact. Tectonic changes to the oceans drainage basin cannot be changed as tectonic activity is completely out of human control.

152
Q

Describe the location of the sundarbans?

A

The Sundarbans is a coastal zone occupying the world’s largest delta that extends over 10,000 km2 of southern Bangladesh and India on the Bay of Bengal.

153
Q

Why did the delta of the Sundarbans form?

A

The delta is formed from the sediment deposited by three of the world’s great rivers, the Ganges, Brahmaputra and Meghna.

154
Q

What are the key ecosystems of the Sundarbans?

A

The key natural ecosystems of the Sundarbans are mangrove forests and swamps.

155
Q

What is the landscape of the sundarbans and why does it see little change?

A

A dense, well-developed, network of interconnecting river channels flows across the clay and silt deposits
Traditionally the location of the network of main channels remained relatively static due to the silts and clays being quite resistant to erosion
The larger channels are generally straight and can become up to two or more kilometres wide, flowing generally north to south due to the strong tidal currents.

156
Q

How do Dunes form in the Sundarbans and how do they affect the systems there?

A

The non-cohesive sediments like sand are washed out of the delta and deposited on banks, where the strong south-westerly monsoon winds then blow them into large ranges of sand dunes
With the protection of the dunes, finer silts washed into the bay are deposited, where wave action then adds and shapes further deposits of sand to form new islands
Vegetation establishes itself and eventually, if the natural vegetation succession can occur, the dense mangrove forests, where species like the endangered Royal Bengal Tiger can develop
However, the equilibrium of the natural processes that exist here is very delicate and further human activity it may be jeopardising its very existence.

157
Q

How is the Sundarbans incorrectly Perceived?

A

The mangrove forests of the Sundarbans are crucial for the wildlife and people living there, providing economic and environmental opportunities, only if managed sustainably
Despite the wealth and service potential many outside and inside Bangladesh view this area as uninhabitable.

158
Q

Why is costal erosion not the main threat to the Sundarbans?

A

Despite the variety of processes at the Sundarbans, costal erosion is not the main threat due to the strength of the clays and silts (they are resistant to erosion).

159
Q

What are the goods opportunities in the Sundarbans?

A
  • Fuel – Charcoal and firewood
  • Construction materials – timber, poles, thatch
  • Fishing materials – poison and floats
  • Household items – furniture, glue and wax
  • Food and drink – leaves, fruits honey, cooking oil, alcohol, vinegar and fish
  • Textiles – furs and skins, synthetic fibres and tannins and dyes
  • Medicines
  • Paper.
160
Q

What are the services opportunities in the Sundarbans?

A
  • Protection services – flooding, erosion, cyclones
  • Provision of: nursery grounds, breeding grounds, fishing grounds and costal livelihoods
  • Maintenance of the environment
  • Value to: culture, spiritual, religion, education and science, recreation and leisure and heritage.
161
Q

What are the threats to the Sundarbans?

A
  • Coastal flooding
  • Cyclones
  • High salinity levels in soils
  • Instability of the islands
  • Accessibility and remoteness
  • Deadly wildlife (Tigers)
  • Over exploitation of valuable resources from vulnerable costal habitats
  • Conversion of wetlands into intensive agriculture and settlements
  • Destructive fishing techniques
  • Lack of knowledge on the environmental and economic significance of the region
  • Resource – use conflicts
  • Lack of awareness on costal issues by decision makers.
162
Q

How are the people of the Sundarbans dealing with the extensive threats they face?

A

Despite the plethora of challenges many live successful lives in the Sundarbans by working with nature rather than against it
Mitigation
Resilience.

163
Q

What two ways have helped make people in the Sundarbans resilient?

A

The wealth of local goods in the area have allowed local populations to survive,
the mangrove forests and dunes themselves offer protection from: storm winds, floods, tsunamis and costal erosion.

164
Q

In what ways do mangrove forests in the Sundarbans make the population there resillient both economically and physically (Specific detail)?

A

It’s believed 30 trees per 0.01 hectares can reduce the severity of a tsunami by 90%
It’s also thought that one hectare of mangrove forest is worth $12,000 per year and as a result (unlike many parts of Bangladesh) it offers resilience against poverty and provides sustainable development for those looking to move there.

165
Q

How and why can people in the Sundarbans Mitigate the threats they face?

A
  • The ever present threat of natural disaster in the Sundarbans has meant there has been significant investment in the area (roads, telecommunications, schools, hospitals, cyclone shelters, flood protection and tube wells) which mitigate the risks they face
  • Many communities of the Sundarbans also have good levels of social capital from the legal frameworks and services provided by a number of formal government and NGO organisations, alongside traditional laws, tenets and social sanctions that communities have used for generations to manage their use of the region
  • There is also economic value to the resources of the area and together with financial resources like access to micro-credit; most Sundarbans communities have a greater economic safety net than other vulnerable groups in Bangladesh.
166
Q

why is the resilience of the people in the Sundarbans decreasing?

A

In recent decades the level of resilience provided by these livelihood assets may be decreasing as poverty and marginalisation of some coastal communities increases due to:

  • shrinking of the open access resources
  • increasing deaths by tigers (if wives are widowed they can often face very limited opportunities in this male-dominated society, especially as many marry very young before completing their formal education)
  • Degradation of ecosystems
  • Conflicts over land usage
  • corruption of both local and national political institutions

However, it is almost certain that Climate change will be the most significant threat the people of the Sundarbans face.

167
Q

What are Future challenges people of the Sundarbans will face?

A
  • Increased frequency and intensity of floods -
  • Flood waters remaining for longer -
  • Permeant embankments built by the shrimping industry are encouraging the deposition of silt which is raising water levels in the rivers –
  • Rising temperatures are leading to the increased salinity of soil -
  • Increased fertiliser and pesticide usage is worsening soil quality
  • Changes to seasonal patterns of rainfall.
168
Q

How will people of the Sundarbans adapt to future problems/threats?

A

• Grassroots NGOs run education programmes to encourage farmers to return to more traditional ecologically-friendly methods
• NGOs provide education and training about community level preparation for natural disasters — planning and preparation can significantly mitigate the impacts of natural disasters
• USAID is training communities to become more resilient to future climate shocks, 30,000 have been taught improved agricultural techniques
• Relaunch of the policy to build multipurpose cyclone shelters equipped with communication equipment and megaphones, which also serve as primary school facilities (this comes after many were built in the 1970’s and many have been neglected since)
• New salt resistant rice varieties that can survive being submerged in sea water for up to 2 weeks
• NGO’s building latrines on higher grounds and the education of communities on waterborne diseases and sanitation
• Installing storage tanks for rainwater in areas that are most at risk of inundation from salt water
• Distributing water tight containers to store important belongings and papers during floods
.

169
Q

Identify the settlements of start bay in order (south to North)?

A 
South Hallsands (submerged) 
North Hallsands 
Beesands 
Sunny dale 
Torcross
170
Q

What are the Key things to remember for each settlement at Start bay?

A

South Hallsands = Lost to the sea after removal of sediment from scerries bank, built on a wave cut platform
North Hallsands = Rip Rap and rock armour, prospect house

170
Q

What are the Key things to remember for each settlement at Start bay?

A

South Hallsands = Lost to the sea after removal of sediment from scerries bank, built on a wave cut platform
North Hallsands = Rip Rap and rock armour, prospect house
Beesands = Rock armour and sea wall
Sunny Dale = Gabions that are privately owned that have led to Coastal squeeze
Torcross = Recurved sea wall and rock armour as well as beach nourshment schemes by Operation tiger monument to protect important A379 transport link

171
Q

What is the difference between GCSE and A Level coastal management?

A

At GCSE we do Hard vs Soft engineering at A level we look at Traditional vs holistic management techniques.

172
Q

Why do we need to use coastal management techniques?

A

Half the world lives withtin 60km of the coast
75% of large cities are on the coast
Coastal areas are under huge and increasing pressure for development ((Costal squeeze (population type)) Leading to environmental damage and habitat destruction.

173
Q

What are the UN’s SDG and the one regarding climate related disasters?

A

Sustainable development goals - by 2030, strengthen resillience and adaptive capacity to climate related disasters and natural disasters in all countries.

174
Q

What are traditional management techniques?

A

Direct action on preventing erosion or flooding on a short section of a coast, focusing on one limited stretch of coast rather than looking at the coastal system as a whole.

175
Q

What are holistic management techniques?

A

Sustainable, long term approaches considering the entire coastal zone, with the goal being to finding a balance between ecological and human needs, with adaptation being a viable option.

176
Q

How many people live in the Sundarbans?

A

Almost 4 million.

177
Q

When were the Sundarbans made a UNESCO world heritage site?

A

1987.

178
Q

What is wave Refraction?

A

the process by which waves turn and lose energy around a headland on uneven
coastlines
The wave energy is focussed on the headlands, creating erosive features in these
areas
The energy is dissipated in bays leading to the formation of features associated with lower
energy environments such as beaches.

179
Q

What are drift aligned beaches?

A

Beaches that run at an angle to the approaching wave front, here drift aligned sediment is deposited along the coast within the process of longshore drift
This can often lead to the formation of a spit.

180
Q

How will sediment size change along a drift aligned beach?

A

Sediment size will decrease the further down the beach we go, as finer particles are more likely to be carried further and become more rounded as they go.

181
Q

What are swash aligned beaches?

A

The wave front approaches parallel to coast so there is limited longshore drift and Sediment doesn’t travel up the beach far

182
Q

What are the key types of Landforms found on coasts of deposition?

A 
Spits (Simple and compound) 
Bars 
Tombolo 
Beaches 
Barrier islands 
Barrier Beaches 
Sand dunes
Estuarine mudflats and saltmarshes.
183
Q

What are the key landforms found on coastlines of erosion?

A

Cliffs
Wave cut notches
Wave cut platforms
Caves, arches, stacks, stumps.

184
Q

What is a spit and how is it formed?

A

Spits - A spit is a long narrow strip of land which is formed due to deposition
Longshore drift occurs along the coast line but as the waves lose energy (normally due to going into a sheltered area such as behind a headland) they deposit their sediment
Over time this
creates a spit
Periodically, the prevailing wind will change direction and tidal power causing a recurved hook to
appear
Over time, the sheltered area behind means that a saltmarsh as energy there is low, as a result a mudflat is formed
Then, alluvium dries creating a salt marsh where vegetation can begin to grow
Plant succession can begin to occur stabilising the spit and forming a more developed salt marsh
The length of a spit is influenced by surrounding currents or rivers.

185
Q

What is a compound spit?

A

A spit that has multiple barbs along the spit.

186
Q

What is a bar?

A

Bars - A spit which, over time,
crosses a bay and links up two
sections of coast.

187
Q

What is the water behind a bar called?

A

A lagoon.

188
Q

What is a Tombolo?

A

When a spit connects with an island off the coast, it may be submerged at high tide.

189
Q

What factors affect the formation of a spit?

A 
The curvature of the beach 
Wave energy 
type of wave 
Direction of prevailing wind 
Currents (Longitudinal current)
190
Q

What is an example of a UK Spit?

A

Hurst castle spit in Hampshire

191
Q

Example of a UK Tombolo?

A

Chesil beach spit, linking mainland Dorset to the isle of Portland.

192
Q

Example of Non UK Spit?

A

The Arabat spit in the sea of Azov, Crimea - it is the worlds longest spit at 70 miles long.

193
Q

How is an Offshore bar formed?

A

When waves approach a gently sloping coast friction between waves and the sea bed cause the waves to break up at a distance from the coast,
Over time more material is deposited and built up away from the coast, forming the offshore bar which is a ridge of sand
The offshore bar can partially or completely cut off a piece of land to form a lagoon
Offshore bars are sediment sinks but can sometimes be sediment sources
as the waves don’t have enough
energy to carry the sediment to shore. They can be formed as the wave breaks early,
scouring the seabed and instantly depositing its sediment as a loose-sediment offshore bar.

194
Q

How do barrier beaches form?

A

When a spit becomes a bar when it creates a barrier beach
Barrier beaches can trap water behind them to form lagoons or freshwater lakes (Like at Slapton Ley)
Barrier beaches on the south coast of England have formed as a result of rising sea level after the last glacial period
Sediment that was in the English channel has been deposited on barrier beaches to build them up.

195
Q

Example of a barrier beach UK?

A

Slapton Ley 5km long (Freshwater lake)

Chesil beach Weymouth 18 miles long

196
Q

What are concordant coastlines?

A

Concordant coastlines are where the rock strata run parallel to the coast.

197
Q

What are discordant coastilines?

A

This is where the rock strata run perpendicular to the sea, which can create successions of
headlands and bays; less resistant rocks are eroded faster than the more resistant rocks, which
leads to the formation of bays.

198
Q

What are barrier islands?

A

Where a beach becomes separated from the mainland, common in areas with low tidal ranges and gently sloping coastlines, found in the Netherlands, and the south Texas coast.

199
Q

What are sand dunes and how are they formed?

A

Dry sand is blown onshore during low tide and sand is initially trapped as the back of the beach by debris, and over hundreds of years vegetation or dune succession takes place
Small embryo dunes form and as they stabilise (allowing pioneer species to develop on them) their pH decreases and Hummus level increases
The pioneer species that grown on the fore dunes like sea rocket and couch grass have become adapted to cope with very dry and salty conditions, not only do they bind the soil together with their roots, but when they die they they add organic matter to the developing dunes
As pioneer species evolve, they bind the soil together creating larger fore dunes where marram grass - a plant with very long roots to reach water - grows which further binds the dune together,
Depressions and slacks form between dunes form just above the water table where aquatic plants can grow
As the environment changes over time, low shrubs begin to form on grey dunes, and on the mature (fully matured dunes) Oak and pine trees and gorse grows, here pH is at is lowest and hummus is at its highest this is known as the climactic climax community.

200
Q

What does the formation of sand dunes require?

A

Sand dunes occur when prevailing winds blow sediment to the back of
the beach and therefore the formation of dunes requires large quantities of sand and a large
tidal range
This allows the sand to dry, so that it is light enough to be picked up and carried
by the wind to the back of the beach
Frequent and strong onshore winds are also
necessary

201
Q

What are the names of each type of dune in order?

A 
Embryo dune 
Fore dune 
Yellow dune 
Grey dunes 
Dune slacks 
Mature dunes
202
Q

How do Ph levels and Hummus levels change as dunes develop?

A

Soil pH decreases (it is highest near the sea as sea water is alkaline)
Hummus levels increase the further back you go (because amount of organic matter is greatest away from the sea.

203
Q

What is Humus?

A

Humus is dark, organic material that forms in soil when plant and animal matter decays.

204
Q

UK example of sand dunes?

A

Sand dunes at Studland bay Dorset, with more than 75 hectares, Studland is the largest area of dune heath on the South Coast

205
Q

How do beaches form?

A

Beaches are made up from eroded material that has been transported from elsewhere and then deposited by the sea
For this to occur, waves must have limited energy, so beaches often form in sheltered areas like bays
Constructive waves build up beaches as they have a strong swash and a weak backwash
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.

206
Q

How are wave cut notches and platforms formed?

A

at a coastline where the lithology is layered vertically and directed to the sea, the sea attacks the base of the cliff with hydraulic action causing a wave cut notch, over time the notch grows and grows causing the cliff to become a large overhang
At the same time the top of the cliff is weakened through sub aerial weathering
over time the cliff can no longer remain an overhang and collapses
The backwash carries the collapsed sediment out to see leaving behind a sloping rocky platform behind as the cliff retreats usually visible at low tide
the cliff collapses time and time again, extending the size of the wave cut platform.

207
Q

What are the three main factors affecting the formation of a wave cut notch/platform?

A

Geology - The substance of rock affects the rate of erosion, the lithology does as well (it will determine if a wave cut notch will form or whole cliff erosion)
Wave energy - Whether there are constructive or constructive waves, as wave cut notches and platforms only occur at high energy coastlines
Tides - High tidal ranges could lead to tidal scour.

208
Q

How are caves, arches, stacks and stumps formed?

A

Headlands from on a discordant coastline where alternating bands of hard and soft rock perpendicular to the ocean erode and form bays and headlands
Because of wave refraction, destructive waves focus their energy all on the sides of the coast, causing the headland to slowly erode over time
In doing so cracks and faults within the inter tidal zone become exposed through hydraulic action which causes the crack to widen
They are further widened by weathering and crystallisation and further erosion through abrasion and hydraulic action is focused on the sides of the fault due to wave refraction, causing the crack to widen to form a cave
eventually the waves break through the cave forming an arch
Biological weathering occurs at the top of the arch combined with the forces of gravity and further weakening and expansion of the arch mean that the arch collapses forming a single isolated stack
Hydraulic action weakens the base of the stack before it too collapses into the sea causing a stump which may only be visible at low tide.

209
Q

what is an example of a UK wave cut notch/platform?

A

Dancing ledge, Dorset near the village of Langton Matravers.

210
Q

What factors affect the formation of a cave / arch /stack / stump ?

A

Geology
Lithology
Wave energy / type of wave.

211
Q

Example of cave arch stack and stump?

A 
Cave = Merlin's cave in tintagel, Cornwall
Arch = durdle door, Lulworth, Dorset 
Stack = Old oman of hoy, orkney islands, Rackwick bay 
Stump = Old harry rocks, swanage bay, Dorset.
212
Q

What are the three conditions that need to be met for a estuarine mudflat to occur?

A
  • Sheltered areas where deposition occurs
  • Where saline and freshwater meet, the rising tides create a buffer to river flow leading to deposition
  • Where there are no strong tides and currents, low velocities mean the sediment deposited is mud
213
Q

how Estuarine mudflats and salt marshes occur?

A
  • Mud is deposited close to the high tide line on a low energy beach, here flocculation occurs and tiny sediments stick together and their combined mass makes them sink to the seabed
  • Pioneer plants such as Eelgrass and Cordgrass start to form in the transition zone, these can tolerate the inundation of saline water as well as supporting the deposition of more sediment
  • Gradually mud levels rise above high tide and and a more developed saltmarsh, with plants that no longer need to be adapted to saline conditions
    Soil conditions improve and vegetation succession continues to form a meadow, the ecosystem in a salt marsh is often known as a halosere
214
Q

What is beach nourishment and how does it protect the coast?

A

Beach nourishment = The addition of sand or pebbles to an existing beach to make it higher and/or wider
The sediment involved in Beach nourishment is typically dredged from a nearby seabed or nearby beach
It helps rebuild a beach,reducing the rate of erosion on the cliffs, acting as a natural defence to both erosion and flooding as well as opening the possibility to bring in increased numbers of tourists.
Beach nourishment aims to minimise the impacts of longshoredrift band the rate at which the coast iseroded and flooded by creating a natural barrier byremoving sediment from one area of a sediment cell and putting it in a more vulnerable/critical location.

215
Q

Where has beach nourishment been used?

A

Slapton sands outside the operation tiger war memorial.

Swanage bay

216
Q

How much does beach nourishment cost?

A

Costs around£3000/m2

217
Q

What are the benefits of beach nourishment?

A

Relatively cheap and easy to maintain
Looks natural and blends in (usually) to the surrounding area
Increasing tourist potential by creating a beach

218
Q

What are the drawbacks of beach nourishment?

A

Needs constant maintenance and looking after
Can disrupt other costal processes (could be similar consequences to the removal of sediment in skerries bank in start bay)
If sediment is taken from other beaches, those beaches become weakened and vulnerable ; it does not mitigate the problem entirely it can just move it elsewhere

219
Q

What is Cliff regrading and drainage and how does it protect the coast?

A

Cliff regrading and drainage = Cliff regrading involves reducing the angle of a beach/cliff to help stabilise it. A steep cliff is typically more vulnerable to collapse, therefore the lower the gradient of a cliff the less vulnerable it is to erosion. Drainage involves the removal of water from an area to prevent landslides and slumping – it also involves the re vegetation of areas.
By reducing the angle of a cliff, theslope is more structurally strong, making it lessvulnerable to the processes ofhydraulic action and corrosion. By draining the cliff, the slope becomes less heavy and lubricated, reducing the risk of mass movement and freeze thaw weathering.
Cliff regrading and drainagereduces the frequency of mass movement on the coast and slows processes like hydraulic action.

220
Q

Where has cliff regrading and drainage been used?

A

Highcliffe in east Dorset (near Christchurch, Bournemouth) where the cliffs have been regraded and drained to reduce erosion to prevent the nearby Highcliffe castle from falling into the sea.

221
Q

how much does cliff regrading and drainage cost?

A

Can cost as much as£1 million per every 100m. But this figure can vary greatly depending on the size and type of rock and size of coast.

222
Q

What are the benefits of cliff regrading and Drainage?

A

Can be very effective on clay and other loose rock where many other strategies may not be effective
Drainage is usually cost effective
Reduces the level of water content in cliffs which most other techniques do not do (prevents cliffs from oversaturating and collapsing.)

223
Q

What are the drawbacks of Cliff regrading and drainage?

A

May look unnatural
Cliff may collapse during the process, or because the cliff is drier it could lead to rockfalls, creating an additional hazard.
Regrading involves the retreat of a cliff, effectively eroding it (carrying out what it is supposed to prevent)
Can be very disruptive and loud during construction.

224
Q

What is Dune stabilisation and how does it protect the coast?

A

Dune stabilisation = the planting of Marram grass on dunes to help bind them and protect the land behind them. Areas are also often fenced off to keep people off the Newley planted dunes.
Stabilisationincreases the dunes’ ability to prevent erosion from wind and water by making them more bound by roots
The strategy can somewhat prevent longshore drift, but mainly absorbs waveenergy, preventing it from eroding the cost(also can act as anatural flood defence)

225
Q

Where has dune stabilisation been used?

A

Port Einon, Pembrokeshire

226
Q

How much does Dune stabilisation cost?

A

Costs around£2 to£20 per meter

227
Q

What are the benefits of dune regeneration?

A

The coast retains a natural look
Provides important costal wildlife habitats for many different species
Relatively cheap
Sustainable
Requires little long-term maintenance once plants are planted and grown

228
Q

what are the drawbacks of dune regeneration?

A

The planting of marram grass is time consuming
The plants themselves (and roots) need time to grow and therefore won’t noticeably affect costal rates of erosion quickly.
People may respond negatively from being barred away from certain area if some are fenced off

229
Q

What are Groynes and how do they protect the coast?

A

Timber rock structures built at right angles to the coast.
They trap sediment being moved along the coast by littoral drift – building up the beach.
It works with natural processes to build up the beach and protects the land behind it.

230
Q

What are the Drawbacks of Groynes?

A

it does starve the beaches further up the coast of fresh sediment because they interrupt littoral drift, often leading to increased erosion elsewhere.
They can look unattractive as they are unnatural.

231
Q

Where have groynes been used?

A

Swanage bay, Dorset

232
Q

How much do Groynes cost and last?

A

£5000 to £10,000 each (at 200 metre intervals)

30-50 years
Wooden groynes may be less like 10-25 years

233
Q

What are sea walls and how much do they cost?

A

A sea wall is a protective shield to the coast made of steel, concrete and stone.

Sea walls prevent the erosion of the coast by reflecting waves or blocking the movement of sediment along the coastline.

Sea walls prevent the erosion of cliffs and movement of sediment that would occur as a result of erosion.

234
Q

Where have sea walls been used?

A

Torcross

235
Q

What are the drawbacks of sea walls?

A

Ugly
Unnatural
Expensive
Large disruption during construction

236
Q

What are offshore reefs and how do they protect the coast?

A

Materials like old tyres/ cement can be placed on the floor of the ocean in the intertidalzone.Ifthis is parallel to the coast then it causes waves to break offshore, and thereforereduces the amount of energy the wave has when it reaches the coastline, therefore there isless erosion. By stopping storm waves reaching the coastline it allows the wider beach todevelop.

237
Q

What are the advantages of offshore reefs?

A

Natural ecosystem is only partially disturbed
Dunes can stabilise onshore
New habitats could be made
Relatively cheap compared to other strategies

238
Q

What are the disadvantages of Offshore reefs?

A

Hazards in navigation
If visible at low tide can look ugly
Disrupt some uses of the beach like jet skis
Difficult to install

239
Q

Where have offshore reefs been used?

A

Sea Palling in Norfolk has offshore reefs, it is one of the only coastlines that does

240
Q

What are tidal barrages and how do they protect the coast?

A

Tidal barrages are dam like structure however instead of stopping the movement of water, the water can infact move in and out of the river or bay. These tidal barrages can be found in the form of roads or bridges, the purpose is to control and reduce the tidal force. They are also a source of power as they generate hydro power.

241
Q

What are advantages of tidal barrages?

A
  • can help prevent low level flooding in certain areas
  • a road can be installed and therefore these can have multiple benefits
  • produce a reliable source of energy
242
Q

What are the disadvantages of tidal barrages?

A
  • very costly
  • lengthen periods of high and low tides, this has a great effect on the eustarine systems
  • shorten tidal range
243
Q

Where has a tidal barrage been built?

A

La Rance Tidal Barrage in France was built 1963, it is one of the most successful barrages in the world.

244
Q

What are the benefits of tidal barrages?

A

Tidal barrages generate a reliable source of energy that is essentially carbon free. They are also very long lasting compared to lots of other strategies.

245
Q

What are the drawbacks of tidal barrages?

A

Total cost of the barrage in France was roughly 620 million Francs which is roughly 94.5 million Euros.

246
Q

What is rock armour and how does it protect the coast?

A

This is where very large boulders are placed on a shoreline interlocking one another, as it is allowing for protection against erosion, specifically in-front of property. However, it can be on the more expensive side.
Rock Armour works by absorbing and deflecting wave impact and energy before they are able to reach any coastline structure.
The main processes that it aims to prevent/slow down are scouring, wave and ice erosion processes.
Mainly the breakdown of natural defences such as sand dunes, would mean that Rock armour may have to be implemented to protect a specifically important section of the coast.

The main source of energy that this method aims to dissipate, or reduce its impact is wave energy, as the rocks disperse the initial impact of the waves.

247
Q

What are the disadvantages of rock armour?

A

A disadvantage of rock armour would be the price, and it’s aesthetic due to the very large size and quantity required for it to be effective.

248
Q

Where has rock armour been used in the UK?

A

A location within the UK that has rock armour in place would be Slapton sands (Torcross).

249
Q

What are the benefits of rock armour?

A 
They are cost effective.
They are highly durable to weathering.
They dissipate energy very well.
They can come in a range of sizes, which means they can be put in at almost any coastline.
They are easy to install.
250
Q

What are revetments and how do they protect the coast?

A

They are sloping structures built on embankments and shorelines or in front of sea walls to help to dissipate wave energy and reduce coastal erosion
They are often constructed as permeable structures; this allows them to absorb the maximum amount of both wave energy and minimising wave run up.
There main functions are to protect the shoreline from erosion and storm surge flooding events.
The main issue with revetments is that they have a high tendency to degrade the beach, and therefore are only put in at points that are hyper-exposed to erosion along the coastline.
The primary sources of energy that they look to prevent are wave energy, and tidal energy, as higher tides can often create more destructive waves/ hit higher areas within the rocks.
There are two specific types of revetments, exposed and buried. Buried are usually used as a part of soft engineering strategies to add more protection against erosion without appearing man-made and out of place.

251
Q

Where have revetments been used?

A

Happisburgh, Norfolk

252
Q

What is marsh creation and how does it protect the coast?

A

A coastal ecosystem found between land and open salt water that is regularly flooded by tides.

Created when mud and silt are deposited along a sheltered part of the coastline such as the inside of a spit. This is because rates of deposition are greater than transpiration due to lack of energy in waves.

The marshland also limits the area in which waves can reach preventing flooding. The marshlands can be created by encouraging the growth of marshland vegetation such as glassworts.

253
Q

Where has marsh creation been used?

A

Holderness
Louisiana coast
Along the Bristol channel

254
Q

What are the disadvantages of marsh creation?

A

Look natural
Provide a biological ecosystem
Sequester climate change therefore helping the climate crisis

255
Q

What are the disadvantages of Marsh creation?

A

Very expensive to maintain and create

256
Q

What are offshore breakwaters?

A

Offshore breakwaters are shore-parallel lines of rocks and boulders designed to reduce the wave energy that reaches the beach.
Therocks break the waves early causing them to lose energywhich reduces the erosion on the beach as well as preventing littoraldrift.
The wavesdon’tcarry sediment up the beach as far, therefore preventinglittoraldrift.
Low energy wavescauses increaseddeposition and for a larger beach to form.
This is effective if the wavesaren’t taller than thedefence and so strongwinds, high tide and wave energywill decrease the effectivenessof the defence.

257
Q

What is an example of offshore breakwater in the UK?

A

Wallaseyhas the first offshore breakwater in Britain constructed for coastal defence (1981), in Merseyside, Liverpool

258
Q

What are the benefits of offshore breakwaters?

A

Theyprotect the shoreline by absorbing wave energy, which reduces erosion, and by changing wave direction, which reduces longshore drift.

259
Q

What are the drawbacks of offshore breakwaters?

A

Low littoral drift may negatively affect other places down the coast.
Can be a problem for small boats which may break on land just below the water.
Can create currents behind the breakwater which is a hazard for swimmers

260
Q

What are the advantages of managed retreat?

A

Creates saltmarsh which can provide a habitat for animals
No construction cost
Natural defence against erosion and flooding

261
Q

What are the disadvantages of managed retreat?

A

Initial construction cost is nothing to the local authorities
Landowners need to be compensated - this can cost between £5,000 - €10,000 per hectare
Is against the point of coatal management

262
Q

Where has managedretreat been used in the UK?

A

Abbot Hall Farm, Essex
First retreat site
8,000 square metres

263
Q

What are Gabions?

A

Gabions are metal cages containing rocks, usually constructed at the base of a cliff toabsorb wave energy and reduce erosion.
They reduce the speed and energy of the water by forcing the water through the small gaps in the cage.
This reduces erosion to the slope behind it whilstprovidinggood drainage and permeability to water.
The effectiveness willbe reducedbywind speed and fetch whichwill in turn increase the waves energy and erosion potential.
Tides will make the biggest difference asif low tide doesn’t reach thegabions, then thecliff won’t beaffected.

264
Q

Where are Gabions found?

A

Found in many parts of the English coastline such as Seaton and Slapton Sands in South Devon

265
Q

What are the advantages of Gabions?

A

Cheap at only £100 per square metre

Reduces wave energy and prevents erosion at the top of the beach

266
Q

What are the drawbacks of gabions?

A 
Short lifespan of only 5 to 10 years
Easily destroyed in storms
When destroyed metal wires can become dangerous and so need constant management.
Looks unnatural, especially when rusted.
Can't prevent against flooding.
267
Q

When is Carbonation more impactful and why?

A

The cooler the temperature, the more carbon dioxide rainwater absorbs, making carbonation more effective in winter.

268
Q

What is the relationship between mitigation and adaptation?

A

Mitigation can restrict impacts of something and therefore can reduce the level of adaptations required by communities and nations, but there is a significant lag time between mitigation activities and their effects, so it may be many years before adaptational requirements are reduced.

Physical Geography (6 decks)

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