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A level- Geography > Coastal Landscapes > Flashcards

Coastal Landscapes Flashcards

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1
Q

The size and energy of a wave can be influenced by:

A
  • how long the wind has been blowing
  • the strength of the wind
  • the length of the fetch
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2
Q

what is a closed system?

A

a system where there is no transfer of energy or matter across the system boundary, eg. the earth as a whole

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3
Q

what is an open system?

A

where there are transfers of energy and matter across a system boundary, eg. the body

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4
Q

what is dynamic equilibrium?

A

when your inputs and outputs mean that the system stays in balance

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5
Q

what is feedback?

A

changes in the system almost always leading to a further change

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6
Q

what is positive feedback?

A

amplifying change in a system almost like a snow borne effect, making it more unstable

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7
Q

what is an example of positive feedback?

A

through the greenhouse effect, radiations heats up our earth, co2 traps the heat, leads to global warming as the planet continues to heat up, leading to increasing temperatures

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8
Q

what is negative feedback?

A

when the system changes and this dampens the initial change, positive, holds the system in a more stable equilibrium

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9
Q

what is an example of negative feedback?

A

more global warming means temps will rise, more carbon trapped in the atmosphere, leading to carbon fertilisation which can increase forest cover, carbon levels to decrease

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10
Q

what is carbon fertilisation?

A

when the carbon is absorbed by the trees, thus lowering the levels

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11
Q

Give three inputs on the coast (what are the three areas)

A

Marine- ocean currents, waves, sediment (erosion of rocks and cliffs)
Atmosphere- wind speed, sun
Humans- settlement, defences

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12
Q

give three outputs on the coast

A
  • sediment transfer
  • ocean currents
  • dissipation of wave energy
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13
Q

give three transfers/flows on the coast

A
  • erosion
  • transportation
  • deposition
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14
Q

give three stores/sinks (coastal landforms)

A
  • beaches
  • headlands and bays
  • wave-cut platforms
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15
Q

how are waves created?

A

by the transfer of energy from the wind to the sea, blowing over the surface. the wind creates ripples that grow into waves as the frictional drag increases

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16
Q

what are swell waves?

A

waves formed by winds blowing over large distances

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17
Q

what is the fetch?

A

the length of open sea over which the wind blows to generate waves

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18
Q

what is a wave period?

A

time take for a wave to travel through one wavelength. it can be calculated by timing 11 waves and dividing them by 10.

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19
Q

what is a wavelength?

A

the distance between two crests

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20
Q

what is wave velocity?

A

speed of movement of a crest in a period of time

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21
Q

what is wave steepness?

A

the ratio of the waveheight to the wavelength

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22
Q

what is wave breaking?

A

it breaks when the ratio is 1:7. The upper part accelerates and the lower part slows down due to friction. This causes the upper part to spil over- causing it to break. the wave height increases but the wavelength and wave velocity both decrease which causes it to break.

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23
Q

what is deep water?

A

the depth of the water is greater than half the wavelength

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24
Q

explain the process of orbital motion

A

winds move across the surface of the water, causing a frictional drag which creates small ripples and waves. this leads to a circular orbital motion of water particles in the ocean

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25
Q

explain the elliptical oscillations of the water particles

A

as waves approach shallow water, when their depth is less than half the wavelength, then friction with the seabed increases. as the base of the wave starts to slow down the circular oscillation becomes elliptical

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26
Q

what is seabed shelving?

A

more friction means its shallower towards the shore

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27
Q

what is the swash?

A

the body of water that reaches up the beach

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28
Q

what is the backwash?

A

the water returning to the sea

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29
Q

what is the crest of a wave?

A

the highest point of a wave

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30
Q

what is the trough of a wave?

A

the lowest point of a wave

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31
Q

what are constructive waves like?

A
  • long wavelength
  • low waveheight
  • strong swash depositing sediment, weak backwash
  • low energy waves
  • 6-10 waves/minute
  • forms a wide sloping beach, sheltered
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32
Q

what are destructive waves like?

A
  • short wavelength
  • high waveheight
  • strong backwash causing erosion, weak swash
  • high energy waves
  • 11-15 waves/minute
  • forms a steep beach, scouring out the area in front
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33
Q

what is the plunge line?

A

where the waves break. it is where the depth of the water and the height of the wave are approximately equal

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34
Q

what are swash-aligned beaches

A

where the waves break in line (parallel) with the coast, beach face orientated parallel to the fronts of the dominant waves. smoothly curved beaches.
- experience minimal longshore drift

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35
Q

what are drift-aligned beaches?

A

produced when waves break at an angle to the coast. swash at an angle but backwash is perpendicular to the beach. as a result, material is transported along the beach via LSD

  • forms when LSD moves material along the coast
  • can have considerable amounts of sediment transported long distances along them
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36
Q

what is refraction on a straight coastline?

A

when waves approach an irregular coastline at an angle they curve and distort. one end of the wave feels the sea floor and slows down while the rest of the wave continues at its deep-water speed. as more and more of the wave reaches the seabed more and more slows down. this leads to the crest changing direction and becomes more parallel to the coastline.

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37
Q

what is the back shore?

A

area between the high water margin and the landward limit of marine activity, changes only happen here in storm events

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38
Q

what is foreshore?

A

the area between the HWM and LWM. most important zone for marine processes

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39
Q

what is inshore?

A

area between the LWM and the point where waves cease to have any influence on the land beneath them

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40
Q

what is offshore?

A

beyond the point where waves cease to impact upon the seabed and in which the activity is limited to deposition of sediments

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41
Q

what is the surf zone?

A

the region of breaking waves, they have already broken

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42
Q

what is the breaker zone?

A

zone in which waves approaching the coastline begin breaking, normally between 5 and 10 metres but this depends on coastline, steeper vs shallow, type of seabed (rocky vs smooth)

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43
Q

what is the nearshore zone?

A

the zone extending seaward from the lower water line beyond the surface zone, it defines the area influenced by the nearshore or low shore.

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44
Q

what is the swash zone?

A

the part of the beach alternately covered and exposed by swash and backwash

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45
Q

what is a storm surge?

A

the pushing of water against a coastline to abnormally high levels, usually a combination of extreme low pressure and high tides

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46
Q

what is a tidal range?

A

the vertical difference in height of sea level between high and low tide.

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47
Q

what is spring tide?

A

tides that occur twice a month when the sun and moon align on the same side of the earth, leading to the highest high tide and the lowest low tide. therefore the largest possible tidal range.

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48
Q

what is neap tide?

A

tides that occur twice a month where the sun and moon are at right angles to the earth, this gives the lowest high tide and the highest low tide. therefore the smallest possible tidal range.

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49
Q

what are tides?

A

the periodic rise and fall in the level of the sea due to gravity.

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50
Q

explain tides in detail

A

as the moon pulls on the earth it pulls water towards it, creating a bulge on one side (high tide). at the same time, the earth is also being attracted towards the moon and that means you have a corresponding bulge on the opposite side of the earth. in the areas between two bulges, the tide is at its lowest.

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51
Q

what does tidal range determine?

A

it majorly shapes the coastline. In the Mediterranean, tidal ranges are low, restricting wave action to a narrow width in the coastal zone. in parts of the British isles, tidal ranges are high which gives a wide zone of wave attack leading to different wave-cut platforms.
- tidal range affects the length of time that the littoral zone is exposed to subaerial weathering

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52
Q

what are ocean currents determined by?

A
  • the rise and fall of the tides
  • wind
  • thermohaline circulation (density differences in water from the salt quantity)
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53
Q

what is river discharge?

A

sediment and fine material brought to an estuary and entering the sea

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54
Q

what is seabed disturbance?

A

severe storms can destabilise material on the sea floor and move it towards the coast

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55
Q

what is cliff and shore disintegration?

A

the transfer of material as cliffs erode and upper beach material is removed into the active zone of coasts

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56
Q

what are sediment cells?

A

an area where the movement of sediment is largely contained. these are closed systems with virtually no inputs or outputs from outside the system.
- the boundaries of cells tend to be on estuaries or major headlands that jut into the sea. the only sediment that can get outside the boundary are very fine pieces of sediment.

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57
Q

what is geomorphology?

A

the study of landforms and their processes and the geological structure, eg. weathering, mass movement, erosion

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58
Q

what is weathering?

A

the breaking two now material in situ

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59
Q

what is erosion?

A

the breaking down of material in response to an agent, either waves, ice, rivers or wind

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60
Q

what are the three types of tides?

A

1) micromareal- tidal range is lower than 2 metres
2) mesomareal- tidal range is between 2 metres and 4 metres
3) macromareal- tidal range is higher than 4 metres

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61
Q

what is chemical weathering?

A

both rain and seawater contain chemicals that can react with chemical compounds in the rock, altering its structure. eg. oxidation, carbonation

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62
Q

what is biological weathering?

A

living organisms can contribute to the weathering of coastal rocks through the activity of plants and animals, eg. plant roots, animals burrowing

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63
Q

what is physical weathering?

A

internal pressures are exerted on rock as a result of changes in the physical structure within its mass, e.g. freeze-thaw, crystallisation

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64
Q

what is hydraulic action?

A

waves break against a cliff face and water forces itself into cracks- compressing the air inside. sheer force of the water.

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65
Q

what is wave quarrying?

A

erosion that happens when high energy, tall waves hit the cliff face and they have the power to enlarge joints and remove large chunks of rock in one go through vibration. this occurs due to the intense force of these waves.

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66
Q

what is cavitation?

A

the opening up of cavities within cliffs due to changes in pressure as waves crash into and out of cracks in the rock

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67
Q

what is abrasion?

A

the launching of rock fragments and pebbles against cliffs by waves, can break off pieces off solid cliff and weaken rock structure

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68
Q

what is solution?

A

chalk and limestone is dissolved and rock is removed in the solution. for example you will see a milky-coloured water.

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69
Q

what is attrition?

A

the smoothing and reducing of angular rock fragments into pebbles, shingle and eventually sand particles

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70
Q

what is mass movement?

A

the downslope movement of material under the force of gravity.
the greater the slope, the greater the force of gravity.

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71
Q

what are the different types of chemical weathering?

A

acid rain- human activities releasing gases that mix with rainwater to form acid, erode rocks

carbonation- co2 in solution found in water produces carbonic acid, this attacks the calcium carbonate and breaks it

hydrolysis- water ions form together with the rock to break it down and produce clay
oxidation- where rocks are exposed to oxygen in the air or water

hydration- where rocks that may include salts absorb water and swell, making them more vulnerable to decomposition

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72
Q

what are the different types of biological weathering?

A

plant roots- roots growing the cracks in the rock, which exerts pressure, eventually splitting the rocks

birds- some birds such as puffins dig burrows into cliffs weakening them

seaweed acids- kelp contains sulphuric acid, which dissolves rock minerals

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73
Q

what are the different types of physical weathering?

A

freeze-thaw- as water enters cracks in he rocks and then freezes it expands in volume causing cracks to develop

salt crystallisation- seawater evaporates, salt is left behind. salt crystals will grow overtime, forcing cracks to grow

pressure release- when the pressure is released from two layers of mass. when the top rock is removed by weathering- the lower rock cracks due to sudden pressure release

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74
Q

what is rockfall?

A
  • greater than 10m/s
  • found on easily exploited rocks that have many joints (limestone, chalk)
  • mostly occurs on vertical cliff faces, leads to scree being built up at the bottom of a cliff
  • example: Burton Bradstock in Dorset, in 2012, 400 tonnes of rock fell, 1 person died
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75
Q

what are landslides?

A
  • from cm per year to 5 m/s
  • found areas of rock that are easily absorbent of water
  • heavy rainfall can reduce friction in cliffs and lead to a landslide
  • example: Bournemouth, east cliff in April 2016, no fatalities
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76
Q

what is runoff?

A
  • moderate speed, cm/s or m/s
  • occurs after very intense rainfall
  • often on the cliff face
  • may be responsible for increasing pollution in coastal areas
  • example: in Manyara region, after 15mm of precipitation in 40 mins in 2013
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77
Q

what is mudflow?

A
  • quite moderate to fast, cm/s to m/s
  • tend to have a lobe
  • an increasing amount of water in the water content of the soil can reduce friction, leading to earth and mud to flow over underlying bedrock, or slippery materials such as clay
  • example: 2017 Sierra Leone mudslide, following three days of torrential rain, 1141 people died, caused by rain, soil erosion and deforestation
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78
Q

what is slumping?

A
  • slow, cm-m per year
  • sand and gravel on the top layer with the impermeable clay on the lower part meaning it slides due to the build up of water
  • contrary to a landslide, the slope is curved
  • land collapses under its own weight
  • example: Barton-On-Sea in Christchurch ha shad significant slumps in the past 20 years, one of the most dangerous was May 2013
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79
Q

what is soil creep?

A
  • very slow, mm/cm per year
  • the movement of soil particles downwards, due to gravity
  • soil tends to get bigger as it absorbs more water which makes it move a miniscule amount
  • can damage fences overtime
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80
Q

what is the littoral zone?

A

the area of land between the cliffs or dunes on the coast and the offshore area that is beyond the influence of the waves. the littoral zone is constantly changing due to:

  • short term factors like storm surges
  • long term factors like changes in sea level
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81
Q

what are three examples of sediment sources?

A
  • rivers (80% of sediment in oceans from rivers)
  • cliff erosion (most frequently in winter due to more frequent storms)
  • longshore drift (sediment moved along beach due to prevailing winds which alter the direction of the waves)
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82
Q

what are the 4 types of transportation?

A

traction- large, heavy sediment rolls along the seabed, pushed by currents
saltation- smaller sediment bounces along the seabed
suspension- small sediment is carried with the flow of the water
solution- dissolved material is carried within the water

83
Q

which part of the UK experiences destructive waves?

A

SW of the UK experiences destructive waves due to the large amount of ocean to the south, fuelling the waves

84
Q

what is refraction on an irregular coastline?

A

as the waves approach the irregular coastline they curve and distort. the wave energy is concentrated on the headland as the ocean is deeper here and so more erosional processes take place. where the waves diverge, they lose power and drop their sediment forming beaches.

85
Q

what are ocean currents?

A

large scale movements of water in the oceans

86
Q

what is the importance of the tides?

A
  • generate ocean currents that influence the direction and scale of coastal sediment movement
  • when high tides are combined with low pressure weather systems an extremely high storm surge can be generated, leading to flooding
  • regular movement of tides can be used to generate renewable energy, e.g swanage bay, Wales
87
Q

explain ocean currents

A
  • the different densities of water are responsible for their movement
  • warm water has a lower density and rises which is why cold water has a higher density and sinks and therefore water comes away form the equator with the cold water which sinks
  • because more of the water is evaporated near the equator it means the salt concentration is higher which is where the Gulf Stream comes in
  • with CC ice caps are melting leading to the salt concentration going down and so density will increase
88
Q

what is the Gulf Stream?

A

one of the most important currents bringing warm water to Europe. much warmer for areas of our altitude, if it wasn’t for the Gulf Stream it would be 5-10º colder. plants can only grow from 6º and so our growing season would be much shorter if it shut down.

89
Q

how do currents affect us?

A
  • they are important to shipping, commercial fishing, recreational boating and safety. knowing the forecasted currents means people can safely dock and undock ships and safely navigate through coastal waters.
  • search and rescue teams use current patterns to determine where the water may carry a missing person
90
Q

how can human activities interfere with sediment cells?

A

1) soft/hard engineering (groins)
2) industry (houses, puts pressure on the cliff face)
3) agriculture (planting on the cliff, roots between cracks expand and make rocks break off)

91
Q

what are the locations of high energy coasts and low energy coasts?

A

high energy- South and SW due to the Atlantic Ocean that surrounds it, fuelling energy

low energy- east of England due to proximity to other landmasses, deposition

92
Q

what are three energy sources on a coastline?

A
  • wind
  • tides
  • ocean currents
93
Q

what is a sediment budget?

A

the balance between changes in the volume of sediment held within the system and the volume of sediment entering or leaving the system. a positive budget is when there are more inputs than outputs to a system and a negative budget is when outputs are greater than inputs. .
input changes: sea level rise putting more sediment in from erosion, damming a river
output changes: human intervention (removing sand for industry), sea level rise means material removed from sediment cells

94
Q

what are four factors affecting erosion?

A
  • waves
  • beach size and presence
  • rock faults
  • rock lithology
95
Q

explain the formation of a headland

A
  • a discordant coastline where alternating bands of rock perpendicular to the coast
  • bands of soft rock are eroded more easily causing the formation of bays which is an inlet of the sea where the land curves inwards (erosion like HA,attrition and solution, chemical weathering such as freeze-thaw happening also)
  • hard rock such as chalk is more resistant to the processes of erosion and so sticks out into the sea, forming a headland
96
Q

explain the formation of wave-cut platforms

A
  • undercutting occurring between the high and low tide mark. HA, wave quarrying, cavitation, carbonation and solution will occur. faults will occur.
  • wave cut notch depends and overhanging cliff will become weaker and unstable and vulnerable to mass movement and eventually falling
  • over time the cliff will recede and leave behind a wave cut platform. the width will depend on the geology of the rock. softer rock erode backwards narrowing the platforms and hard rock will remain protruding into the sea.
97
Q

how are caves, arches, stacks and stumps formed?

A

1) wave energy is concentrated at headlands, leading to erosion forming cracks through HA and salt crystallisation
2) overtime the cracks widen and wave cut notches form. further erosion will form caves
3) due to wave refraction the waves energy is concentrated on sides of headland deepening the cave
4) further erosion leads to an arch. vertical joints form along the bottom of the arch and widen. arch then becomes unstable and falls forming a stack.
5) over time, weathering and erosion causes the stack to become a stump. further erosion leads to broken material to be transported away and deposited in the bay

98
Q

what are negative feedback mechanisms?

A

they can help to restore a coast. during a storm part of a cliff may collapse so the material will protect the base of the cliff from erosion, reducing further cliff recession.

sand dunes may be eroded during a storm meaning a loss of sediment on land. however the sediment produced may be deposited in offshore bars which protect the coastline from further erosion by dissipating wave energy.

99
Q

what is longshore drift?

A
  • when waves approach the shore at an angle and material is pushed up the beach by the swash in the same direction as the wave approaches
  • usually follow the direction of the prevailing winds, SW
  • as a result the waves break onto the beach at an angle of 45º and then backwash drags material back down perpendicularly.
  • over time sediment moves in this zigzag fashion along the coast
  • obstacle such as groynes interfere with LSD and accumulation of sediment happens on the windward side of the groynes leading to entrapment of material
100
Q

how are beaches formed?

A

beaches are formed at the point where the land meets the sea and represents the accumulation of sediment deposited between spring tides and the highest point reached by storm waves. sands end to produce a more gentle gradient due to the lack of percolation. they are made up go ridge and runnels, ripples, cusps, berms and storm beach

101
Q

what are ridges and runnels and how are they formed?

A

description: series of ridges and troughs running parallel to the coast near the low water mark
formation: the ridges are formed by deposition during backwash and the runnels are formed when water moves back to the ocean

102
Q

what are ripples and how are they formed?

A

description: relatively small, elongated ridges that form on the beach
formation: waves and currents flow across loose sand which is dragged along the bottom and is pulled up

103
Q

what are cusps and how are they formed?

A

description: semi circular shaped depressions with coarser material around the edge and finer material in the middle
formation: formed by the waves reaching the same point and backwash scouring out the finer material in the centre

104
Q

what are berms and how are they formed?

A

description: a series of small ridges that form near the high tide mark
formation: deposited by the swash of constructive waves

105
Q

what are storm beaches and how are they formed?

A

description: a ridge found near the back of the beach composed of larger sediment
formation: deposited by waves during storm events

106
Q

what are spits?

A

a long, narrow beach of sand or shingle with one end attached to the shore and the other extending into the sea or estuary

107
Q

what is a compound spit?

A

a spit that shows evidence of a series of sequential growth and recurvature

108
Q

what is the Proximal point?

A

where the spit joins to the mainland

109
Q

what is the distal point?

A

the furthest point of the spit that extends from the headland

110
Q

explain the formation of a spit

A

1) sediment is carried by LSD due to the prevailing winds
2) a change in the shape of the coastline or a sudden interruption by a river estuary causes deposition to happen. a long ridge of material is deposited in the more sheltered water. this is the spit.
3) as the material rejects eastwards storms build up more material giving a greater degree of permanence to the feature.
4) a hooked end can form if there is a change in wind direction. through wave refraction it curves the spit into the more sheltered water.
5) waves can’t get past the spit and so it is very sheltered. overtime, salt marsh and sand dunes develop.

111
Q

give an example of a spit

A

spurn head, Holderness coast

  • 280 acres above water
  • stretching for 3.5 miles across the humber estuary
  • now has a temporary road and the only permanently manned lifeboat station in the UK
112
Q

how is a tombolo formed?

A
  • a spit that joins from the mainland to an island
  • where a spit forms on a coastline where there is a small offshore island and the ridge of beach sediment is deposited towards the small island, a tombolo is formed.
  • formed due to wave refraction off the coastal island reducing wave velocity
113
Q

give an example of a tombolo

A

Chesil beach, Dorset coast

  • 30km in length
  • the high of the shingle ride increases in height eastwards, the size of the shingle also gets larger
  • faces south-west (swash-aligned)
114
Q

how is a bar formed?

A
  • a spit can grow across a bay and join two headlands together
  • they can trap shallow lakes behind the bar, these are known as lagoons
  • some bars may be the revealing of offshore material following the last ice age, as sea levels rose
115
Q

give an example of a bar

A

Slip-on sands, devon

- believed to have been formed y the revealing of offshore material following the last ice age, as sea levels rose

116
Q

how is vegetation essential in stabilising coastal landforms such as dunes?

A
  • roots of plants bind soil together which helps to reduce erosion
  • when completely submerged, plants provide a protective layer for the ground
  • plants reduce the wind speed at the surface and so less wind erosion occurs
117
Q

what is a sand dune?

A

an accumulation of sand grains shaped into mounds and ridges by the wind in coastal areas

118
Q

what do you need for a sand dune?

A

1) wind- preferably mainly onshore winds
2) a plentiful supply of sand
3) a large tidal range- lots of sediment to be brought in, when tide recedes the wet sand will dry out, it needs the time to dry to blow inland
4) on-shore currents carrying seeds

119
Q

how does a sand dune form?

A
  • when the sands dry out they are carried through saltation along the beach, where there is a large tidal range, large amounts of sand are exposed at low tide and this further contributes to dune formation
  • an object is needed (litter, shoe, wood) for the sand to start building up against
  • pioneer species will start growing on the strand line (sea rocket)
120
Q

what is an example of a pioneer specie

A

Saltwort. these are found on the strand line.

121
Q

what is the order of the sections of a sand dune?

A 
strand line
embryo dunes
fore dunes
white/yellow dunes
fixed dunes
dune slack
dune scrub
dune heath
woodland
122
Q

what is on the strand line?

A

These are the youngest dunes. only high specialised plants- pioneers can colonise such environments

Saltwort

  • these must be able to sustain high winds, be drought resistant (xerophytic) and very heavily salt resistent (halophytic)
  • roots grow laterally and vertically for increased support
  • rounded leaves so more resistant to wind
123
Q

what is on the embryo dunes?

A

dominated by specialised grasses. sand accumulation which persists above the high tide line may be suitable for the first perennial plants.

sand couch:

  • tolerant of occasional immersion in salt water (in case of storm surges)
  • tolerant of drought
  • tall and flexible leaves to cope with winds
124
Q

what is on the fore dunes?

A

upward growth of the embryo dunes allows the dune surface to be raised so that it is out of reach of all but the highest storm tides

marram grass

  • extremely long roots
  • has rhizomes which helps it keep very anchored into the ground
  • holds the beach together, allows the dunes to develop as it builds up dense vegetation
  • leaves roll inwards to keep in moisture
  • when it dies it puts lots of organic material in soil, supports further growth
125
Q

what is on the white/yellow dunes?

A

sand sedge

  • extensive shallow rooting system allows this species to exploit moisture from shower summers
  • Does well in waterlogged areas
  • Connected by rhizomes which anchor the plant
126
Q

what is on the fixed dunes?

A

when the vegetation has developed so that it forms a cover on the substrate, the dunes are said to be ‘fixed’
organic layer has started to form on the soil surface

harebell

  • tough and resilient for strong coastal winds
  • cannot handle dampness
  • how in clumps due to delicate stems
127
Q

what is on the dune slack?

A

depending on the height of the water table, areas between sandy hills may be damp or even contain standing water

Creeping willow

  • Low growing so protected from the winds
  • Creates a higher biomass so the lack of grazing permits woody plants, which will form shrub
  • High amount of invertebrates
128
Q

what is on the dune scrub

A

in the absence of grazing animals, tall body plants such as birch form natural invaders. tend to be species-poor

birch

  • Branches are flexible so they don’t break
  • Loss leaves in winter to minimise moisture loss
  • Reach up to 30-50 m in height
129
Q

what is on the dune heath?

A

if grazing pressure from animals prevents the development of a scrub or woodland then the fixed dune grasslands will be a different vegetation type: plagio-climax because it results from human actions.

Heather and gorse

  • narrow leaves to stop the plants from losing too much water
  • they need to be able to tolerate the dry, acid and nutrient poor substrate
  • heather plants grow together to support the high winds
130
Q

what is on the woodland?

A

deciduous woodland is the natural climax vegetation of the dune system. they can experience human intervention with golf courses and plantations. this causes a plagio-climax vegetation.

pine

  • evergreen to maximise photosynthesis
  • thin and waxy needles minimise water loss
  • grow in packs to keep warm from cold and windy conditions
131
Q

what are blowouts?

A

where wind has been funnelled through areas and has removed the sand. wildlife or human activity can often be a catalyst for the formation of blowouts.

132
Q

what factors impact the amount of energy affecting a coastline?

A

1) human interference
- management (groynes, beach replenishment)
- settlement (wearing the cliff face)
- industry (taking sand for industry)

2) wind
- more powerful, how long it has been blowing for, high energy, more erosion

3) fetch
- longer the fetch more energy built up, water fuels the waves, SW England explain

133
Q

what is a statistic on the rate of co2?

A

co2 has increased by 40% from 1800 to 2012

134
Q

what is a statistic on the sun’s output within the years?

A

direct satellite measurement since the 1970’s show no net increase in the sun’s output

135
Q

how do sea levels change?

A

on a day to day basis the sea level changes according to the tide but the sea level also changes on a much grander scale too. these changes are normally caused by ice ages or other major global events. sea level change is categorised into two categories, eustatic and isostatic change depending if they have a local or global effect on the sea level

136
Q

how has sea level changed in the past to now?

A
  • sea levels overall been rising since 1880
  • by 2000 there had been a sea level rise of just under 20cm, continuing to rise
  • rate of rise increased recently to 4/5mm per year
  • rate of future rise uncertain with average predictions varying between 18 and 59 cm compared to 1990s levels by 2090.
137
Q

what is eustatic change?

A

global change in sea level
variations in relative sea level resulting from changes in the amount of liquid water entering the oceans, eg. glacial melt water pouring into the oceans at the end of an ice age

138
Q

what is isostatic change?

A

local change in sea level
rising or falling of a land mass relative to the sea resulting from the release of the weight of the ice after the last ice age. at the end of an ice age, isostatic rebound occurs. the land rebounds back and so sea levels fall. as the weight of the ice is removed, the land will start to rise causing relative sea levels to fall. melting ice caps leads to sea level rise.

139
Q

what are the 4 causes of sea level rise?

A

1) thermal expansion of the oceans- as temps increase the seawater expands, increasing the volume contained in the oceans, contributes to 0.006mmm of sea level rise a year.
2) storage of oceans water as ice in ice sheets- this causes SL change of 10 m-200m. growth of ice sheets typically takes tens of thousands of years to lower sea level whereas melt-out would take thousands of years. through greenhouse gases going up along with temps it means the ice may be released into the oceans as it melts. difficult to predict how the massive ice sheets will behave during future warming.
3) Isostatic rebound- when large ice sheets cover the land it weighs down the land and makes it sink. when the ice melts the land begins to rise as the weight is removed. this is called isostatic readjustment.
4) tectonic uplift- anywhere where you get two tectonic plates meeting you see mountains folding, you can also see tectonic rifting where the plates pull apart causing sea level ribs to drop down, tectonic adjustment after ice ages when the ice melts the land begins to ruse as the weight is removed

140
Q

where is there isostatic rebound in the UK?

A

the north of the UK is still seeing isostatic rebound from previous ice ages so they see sea levels going down and land is rising.
the south of the UK sees sea levels going up as the land is sinking.

141
Q

what is an emergent coastline?

A

a coastline exhibiting features associated with falling sea levels, e.g. raised beaches, former wave-cut platforms

142
Q

what is a submergent coastline?

A

a coastline exhibiting features associated with rising sea levels, e.f. Rias

143
Q

what are the economic, social and environmental impacts of climate change on coasts?

A

economic- cost of installing new defences, destruction of builds affects local businesses
social- loss of housing through increased erosion, displacement of people
environmental- affecting carbon cycle, melting of permafrost means higher co2

144
Q

what are two potential positive impacts of climate change?

A
  • less reliance on imports for agriculture

- possible formation of new landforms, tourists

145
Q

what are the IPCC’s predictions and Pfeffer’s predictions for sea level change by 2100?

A 
IPCC= 0.6 - 1.9 ft
Pfeffer= 2.6 - 6.6 ft

here we can see it is very difficult to predict our pop and consummation in 85 years time

146
Q

what are the overall predictions for sea level rise for the future?

A
  • sea level rise of perhaps 20cm by 2030
  • perhaps a rise of up to a metre over the next 100 years. others say only half a mere.

IT IS V HARD TO PREDICT

Uncertainty increases as we move from the natural sub-system to the human sub-system, with the largest uncertainties concerning their interaction

147
Q

what processes are the changes in sea level the result of?

A

1) increases in the volume of the ocean

2) subsidence of the coast

148
Q

explain the international coastal adaptation approaches

A

the environment agency is responsible or creating a national flood and coastal risk management strategy, under the flood and water management act, 2010

USA: range of coastal adaptation approaches, no universal long term strategy

Netherlands: due to ht amount of land at risk a national strategy has been developed for coastal adaptation. government will no longer provide protection for new development in high-risk areas.

UK: no strategy

149
Q

what are 4 effects of rising sea levels?

A

1) Increased coastal flooding and erosion, unless action is taken to mitigate it (social, environmental and economic)
2) Major rail and road links near the coast are also at risk and several power stations are located on low-lying ground (social and economic)
3) Through gradual uplift from the removal of the glaciers after the last ice age and gradual subsistence occurring on the margins of the north sea basin in the east and southwest it has led to the loss of numerous of villages with low-lying coastlines
4) Impacts underground water resources. The zone where seawater mixes with fresh water in rivers is dynamic and a rise in sea levels can cause it to move upstream

150
Q

what are the impacts of sea level rise on human use of the coastline?

A

1) Residential property / Agriculture
- In the UK more than 26 million people live in major urban areas in the coastal zone
- 57% of the most productive agricultural land is below the 5m contour

2) Coastal industries / economies
- Several power stations are located on low lying land
- Significant loss of income / economic loss if agricultural land is flooded

3) Tourism
- The impacts of rising sea-level on the scenic value of coastline affects tourist revenue
- As the tide becomes higher, beaches are smaller

4) Wildlife habitats
- Coastal ecosystems (sand dunes and salt marshes) are at risk
- Coastal ecosystems are important for coastal protection and they are home to some of the most important/spectacular wildlife

151
Q

what is the Maldives like?

A
  • 1200 islands
  • 80% no more than 1m above sea level
  • Population = 360,000
  • Main industry = Tourism
152
Q

what are the Maldives doing to fight the rising sea levels?

A
  • Building artificial islands
  • Buy land on the main land
  • Coastal management
  • Coral reef
153
Q

explain the building of artificial islands in the Maldives

A
  • Hulumale is currently only home to the country’s airport.
  • It is being expanded using sand, concrete and shingle to cover a total of 697 hectares.
  • Eventually, the government hopes that Hulumale and 7 other islands will be at least 3 meters above sea level.
  • They will also have reinforced sea walls and breakwaters built around the island’s coastlines
154
Q

explain the use of coastal management in the Maldives

A
  • They are increasing beach nourishment and breakwaters to protect their beaches more.
  • The hope is that this will also preserve the 30% of their economy that comes from tourism.
  • They are also encouraging the growth of coral reefs, a very sustainable way of protecting the land as they absorb some of the destructive power from waves, whilst also providing a new tourist attraction.
155
Q

what statistics have the IPCC given on temp rise and rainfall in the Mediterranean region?

A

The IPCC have predicted that the region will experience a rise of 2-5.5 ºC by 2100.
Rainfall will decrease by 20%
The Mediterranean will experience up to five times as many dangerously hot summer days by 2100 as currently occur.
Food security to become a major issue especially in the southern Mediterranean region.

156
Q

How will a 1m sea level rise by 2100 affect Egypt?

A
  • flooding of 25% of the delta, forcing about 8 million people from their homes and this could be worse if the expected doubling of population occurs by 2050.
  • the nation’s food supply would be decimated, as nearly half of all crops are grown here.
157
Q

explain sea level rise on the UK

A
  • an estimated 30% of the population of England and Wales live within 10km of the coast
  • the south of the UK is sinking at a rate of around 1mm per year in comparison to global mean sea levels, whilst the north is rising at a rate of 1mm per year.
  • “Half of the world’s population live within 60km of a coast and 3/4 of all large cities are a the coast” (UNEP)
158
Q

what are the shoreline management plans for the UK?

A

due to the length and variety of the English coastline, no single approach is suitable to adapting to all coastal changes, through sea level rise or otherwise.
they do not have a current policy of compensating those at risk of losing their properties. however the environment agency and defer provide experibste and some funding for local government to develop plans.
There are 22 SMPs around the coast of England and Wales.
first generation plans were aimed at raising awareness of changing coastlines whereas second generation plans currently have started to incorporate predictions of sea level rise into long term plans for coastal defences due to predictions being recently made
The Thames Estuary 2100 project has outlined timelines specifying how tidal defences will need to be improved using the highest scenario to specify worse case sea level rise.
Defra has committed to a £6000 coastal erosion assistance grant for homeowners that are at risk of losing property to coastal erosion. This contributes to costs of demolishing the property and some basic moving costs.

159
Q

what are the international coastal adaptation approaches (shoreline management plans) around the world?

A

USA: range of coastal adaption approaches, no universal long term planning strategy
Netherlands: due to the proportion of land at risk from sea level rise, a national strategy has been developed for coastal adaptation. the government will not provide protection for new development in high risk areas.
France: statutory but non mandatory relocation assistance for properties in areas of risk assessed to be worthy of intervention

160
Q

what is adaptive capacity?

A

the ability of a system to evolve in order to accommodate climate changes or to expand the range of variability with which it can cope. The adaptive capacity of an area is to cope with the effects of severe climate impacts if there is a lack of physical, economic and institutional capacities to reduce risks.
Maintaining and enhancing both resilience and adaptive capacity for weather-related hazards are critically important.

161
Q

how can we improve a country’s adaptive capacity?

A

having policies that enhance social and economic equity, reduce property, increase consumption efficiencies, decrease the discharge of wastes, improve environmental management, and increase the QOL of vulnerable coastal groups can collectively advance sustainable development and hence strengthen adaptive capacity.

162
Q

what are the two responses to climate change?

A

adaptation (coastal planning and management)
mitigation (reducing greenhouse gas emissions)

Hence Nicholls and Lowe and Tol argue that adaptation and mitigation need to be considered together when addressing the consequences of climate change for coastal areas.

163
Q

explain the impact of climate change on tourism?

A
  • leading to different destinations
  • impacts of climate change on coastal tourism are due to coral reef degradation
  • temperature and rainfall pattern changes may impact water quality in coastal areas and this may lead to more beach closures
  • summer heatwaves I the Mediterranean may lead to a tourism shift to spring and autumn and instead a growth of tourism around the Baltic and North Seas in the summer
164
Q

how do the impacts of climate change differ by location?

A

differences in geological, oceanographic and biological processes can also lead to substantially different impacts.

  • deltas/estuaries, coral reefs, sand and gravel beach, soft cliffs and ice-dominated coasts appear most vulnerable to either climate change or associated sea-level rise
  • a lack of adaptive capacity is often the most important factor that creates a hotspot for human vulnerability, greater access to wealth and technology generally increases adaptive capacity, while poverty decreases it
165
Q

what are the threats that the North Norfolk Coast suffer from?

A
  • increasing sea level
  • coastal erosion
  • urbanisation, pollution, tourism and port development
166
Q

give statistics as to what is going to happen to the north Norfolk coast due to climate change?

A
  • the loss of 588 hectares of freshwater grazing marsh and reedbeds mainly at Cley-Salthouse and Titchwell
  • 30% increase in the frequency of gales in the UK by 2050, Norfolk will be particularly at risk
167
Q

how is climate change going to affect tourism on the North Norfolk coast?

A
  • They received in 1993 2.9 million visits, generating an income of £425 million
  • beach areas are to be reduced, less space for each visitor
  • sandy beaches may become stonier with an increase in storminess resulting from climate change
  • scenic value of coasts is also diminished if more hard engineering defences like concrete sea walls and rock armour become necessary
168
Q

what is hard engineering?

A

involves the building of entirely artificial structures using various materials such as rock, concrete and steel to reduce or stop the impact of coastal processes

169
Q

what are groynes?

A
  • Timber or rock structures built at right angles to the coast. They build up the beach by trapping sediment being moved along the coast by longshore drift.
  • it works with natural processes to build up the beach
170
Q

what are the pros and cons of groynes and an example of them?

A

pros:
- not too expensive
- increases tourist opportunities
- protects the land behind it

cons:

  • causes beaches further along the coastline to be starved, increasing erosion, barton-on-sea has erosion as fast as 1m a year due to groynes in bournemouth
  • unattractive to many tourists

Bournemouth

  • they have 56 groynes between Bournemouth and Hengistbury Head, maintaining a large beach
  • tourism is worth £472 million a year so the council are to spend £50 million over the next 100 years.
171
Q

what is a sea wall?

A
  • Stone or concrete walls at the foot of a cliff, or the top of a beach. They are usually curved to reflect waves back out to sea.
  • It is a very effective defence against erosion. They often have a promenade for people to walk along.
172
Q

what are the pros and cons of the sea wall and an example of them?

A

pros:

  • very effective
  • often have a promenade and so adds to tourism

negatives:
- very unattractive
- expensive to build and maintain
- cause erosion further out to sea

Blackpool

  • In 2008 they invested £68 million on a 3.2km sea wall and promenade to protect 1500 homes and businesses
  • stated by the ‘ICE’ as one of the best schemes and allows for more tourism
173
Q

what is rip rap?

A

Large rocks placed at the foot of a cliff, or at the top of a beach. It breaks up the energy of the waves whilst allowing water to still pass through.

174
Q

what are the pros and cons of rip rap and an example of them?

A

pros:

  • cheap and easy to construct and maintain
  • can be used for recreating such as fishing and sunbathing

cons:
- rocks are usually not local so can look out of place
- can be dangerous if people climb over them
Rip rap collapsing in Oregon

Wuthernsea on the Holderness Coast
- uses rip rap and sea wall for double protection, protection of the sea wall through the rip rap

175
Q

what are revetments?

A

Sloping wooden or concrete structures placed at the foot of a cliff or top of a beach. They break up the waves’ energy.

176
Q

what are the pros and cons of revetments and an example of them?

A

pros:
- relatively cheap to build, up to £4500 per metre

cons:

  • very unnatural looking
  • need a high level of maintenance

Mapleton on the Holderness Coast
- successful in reducing erosion but has starved the coastline further down of sediment but it is a very low cost solution

177
Q

what is offshore breakwater?

A

A partly submerged rock barrier, designed to break up the waves before they reach the coast.
An effective barrier that does not obstruct the beach in any way.

178
Q

what are the pros and cons of offshore breakwater and an example of them?

A

pros:

  • doesn’t obstruct the beach in any way, increased area for tourism
  • good for ecosystems, restores beach vegetation
  • protects the beach and the land behind it
  • good for watersports

cons:

  • visually unappealing
  • a potential navigation hazard
  • Korea constructed them on clay and meant that it was unstable

Sea Palling

  • they have been effective in protecting the beach and area behind it
  • introduced watersports opportunities, money
  • their success has meant there are soon to be more of these schemes introduced
179
Q

what is soft engineering?

A

uses natural systems for coastal defence, it involves manipulating and maintaining these systems without changing their fundamental structures.

It is often more preferred as it looks less artificial and out of place. different stakeholders are not always happy with hard engineering as it seen as an unsustainable method of management.

180
Q

what is beach replenishment?

A

Beach replenishment or beach nourishment is the process by which sand is replaced along the beach.
Replenishing the beach makes the beach more effective at dispersing the energy of the waves. It replaces the material lost by longshore drift.

181
Q

what are the advantages and disadvantages of beach replenishment?

A

pros:

  • It avoids the negative effects of hard engineering structures such as sea walls and does not look artificial in any way.
  • maintains tourism

cons:

  • beach replenishment has to be continuously carried out, making it expensive.
  • It is done so through taking material from the sea bed and dumping it onto the shore, costly
  • This involves the use of a dredger which is noisy and upsets tourism and kills marine life from the sea bed. Noise pollution.
182
Q

what is managed retreat?

A

Managed retreat involves allowing the coast to take back the land, by removing existing sea defences and allowing the land behind them to flood.

183
Q

what are the advantages and disadvantages of managed retreat?

A

Advantages:

  • Marsh land will appear on the land allowing for habitats to form, increased biodiversity
  • Marshland can act as a natural sea defence protecting the land behind it from erosion
  • A fairly cheap sea defence

Disadvantages:
- It allows land to flood and become eroded, this causes conflict as to which areas can become flooded

184
Q

what is cliff regrading and drainage?

A

Reducing the angle of a cliff to stabilize it. Drainage removes excess water to prevent landslides and slumping.

185
Q

what are the advantages and disadvantages of cliff regrading and drainage?

A

Advantages:

  • Very effective on clay or loose rock cliffs
  • Relatively cheap way of management

Disadvantages:

  • Draining of the cliff can dry it out too much and cause it to crumble and collapse
  • Some homes on the cliff may need to be demolished as it effectively causes retreat
186
Q

what is Dune Stabilisation?

A

Methods such as planting of marram grass and fencing off areas are employed to protect the dunes from erosion.

187
Q

what are the advantages and disadvantages of dune stabilisation?

A

Advantages:

  • Maintains a natural coastal environment
  • Provides wildlife habitats
  • Cheap and sustainable

Disadvantages:

  • Time consuming
  • May still be eroded if people ignore signs and fenced off areas
188
Q

explain the placement of the Holderness Coastline

A
  • goes from the clay cliffs of Flamborough, to spurn head where a large spit guards the entrance to the Humber Estuary
  • it is one of the most rapidly eroding coastlines in Europe due to the clay geology and high-energy environment
  • historical records show that 29 villages have fallen into the sea since Roman times
189
Q

what physical factors are at work along the holderness coastline?

A

1) Weather
- winter storms produce stronger waves and higher sea levels (surges)
- the saturated clay cliffs suffer increased runoff leading to slumping and other forms of mass-movement

2) Waves
- destructive waves erode the beaches and attack the foot fo the cliffs, removing the clay in suspension, LSD then carries this

3) Geology
- the two main types of rock found along the coast are chalk and boulder clay
- the boulder clay cliffs to the south are more easily eroded and their retreat has formed the sweeping bay of Holdernesss

190
Q

what features and processes make this coastline so distinctive?

A
  • the impressive chalk headland and cliffs near Flamborough
  • the retreating clay cliffs of the Holderness Bay
  • the 6km spit at Spurn Point
191
Q

what is flamborough head like?

A
  • the headland illustrates how wave erosion can produce the classic arch, stack, stump and wave-cut platform features, often associated with chalk rock.
  • the chalk is resistant to erosion and has a distinctive lithology.
  • as the cliffs retreat a noticeable notch indicates how powerful wave energy can be.
  • sub-aerial processes such as rock falls work together with sea processes to create these headland features
192
Q

what are the holderness cliffs like?

A
  • he boulder clay cliffs are formed from material left by ice sheets. they are retreating at an average of 1.8m a year.
  • at the cliff-foot the fine clay is easily removed by waves and it is estimated that LSD carries half a million tonnes of sediment southwards each year in suspension. there is therefore little sediment to form beaches.
193
Q

what is spurn head like?

A
  • sediment is deposited here where the winds, waves and river estuary have created a large but fragile recurved spit
  • spit is growing by 10cm every year
  • it is referred as a littoral cell. they are open systems with inputs, transfers and outputs of water and sediment
194
Q

what human factors play a part along this coast?

A

1) the presence of people along the coast
- threatens life and property
- increasing population due to the development of leisure and holiday facilities have occurred around Bridlington and Hornsea. caravan parks are popular.

2) interfering with natural processes
- interfering of LSD and implementing unsuitable defence strategies can have adverse effects. the impacts of groynes at Mappleton mean that sediment is being prevented from building beaches elsewhere. leads to increased erosion in other areas.

3) global warming
- rise in sea level and increasing storminess
- areas such as spurn head are at great risk in such conditions, from both coastal flooding and erosion

195
Q

what is the protection along the northern part of the Holderness coast?

A
  • there is little need to protect the coast as beach material is relatively stable.
  • erosion increases southwards but there is still a balance between the rate of cliff erosion and sea removal
196
Q

what defences do skipsea have?

A

they have a series of Gabion cages built by the local landowner, though areas eaters die of his caravan and leisure site are still eroding

197
Q

what defences do Hornsea have?

A

this is a holiday resort with a promenade and hotel frontage. this is a very important tourist feature and protects the seawall.
- 1.86km of concrete seawalls, groynes and rock armour
They have put in new groynes, costing £5.2 million. They have caused scour at Mappleton.
Steel ‘doors’ guard the entrance to the beach
The old seawall has been raised slightly. sea level rise.
Sand dunes are being planted with trees.

198
Q

what defences do withernsea have?

A

another resort further south from Hornsea

  • 2.26 km of concrete sea walls, timber groynes, rock armouring and a small offshore rock armour reef along the withernsea frontage
  • a new wave return wall has been built and is protected by rip-rap or rock armour and some beach nourishment
199
Q

what defences do spurn head have?

A
  • problems of erosion
  • the management strategy here is described as ‘abandonment’, since 1995
  • it could no longer afford to repair the damage following successive winters when storms washed over the neck of the spit
200
Q

how successful are the management schemes in Mappleton?

A
  • erosion rates have been long recorded, and in 1786 the village was 3.5km from the sea. By 1988 the sea was on its doorstep.
  • after tremendous pressure from local residents to save the village a scheme was implemented in 1991 at a cost of £2.1 million by EU funding
  • the scheme included two rock groynes, a rock revetment and cliffs being re-graded to reduce slumping and beach nourishment to encourage deposition. Also a new access road was built and a car park and toilet for visitors.
201
Q

what are the three factors affecting the erosion of the holderness coast?

A
  • geology (clay)
  • power of waves (destructive)
  • eroded material
202
Q

why is the sea always brown along the holderness coast?

A

due to high amounts of erosion, the rock is dissolved

203
Q

why did Mappleton get lots of coastal defence?

A
  • the main road is just 34m from the sea
  • many stubborn people, kept on asking for protection
  • kept many businesses open
  • tourist beach allowed people to get a mortgage

HOWEVER, their protection led to increased rates of erosion 3km down at Cawden due to the groynes

204
Q

why do many think that it is no longer sustainable to defend the holderness coast?

A

Economically not sustainable. Looking at £10 million in the future.
The area is not economically beneficial. 237 homes may be in the sea in 85 years.
Seven metres of erosion has occurred in just under a year. Rates of erosion have tripled.

A level- Geography (3 decks)

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