Coasts Flashcards
1
Q
Name the 3 processes within the coastal system
A
Erosion, deposition, transportation
2
Q
Outputs of the coastal system
A
Crack, cave, arch, stack, stump Cliffs Headlands and bays Spits Bars and tombolos Sand dunes Wave cut notches Beaches Wave cut platforms
3
Q
What is a sediment cell?
A
A well defined boundary in which sediment can be transported around and form a depositional landform
4
Q
How does a high energy coastline differ from a low energy coastline?
A
High energy = lots of inputs, processes and outputs (destructive waves)
Low energy = not as much (constructive waves)
5
Q
What 3 factors acquire the energy of a wave?
A
- The strength of the wind
- The length of time the wind is blowing
- The fetch (the distance of which the wind blows over)
6
Q
Give me 6 features of constructive waves
A
Low energy, frequency, steepness and in proportion to length. Strong swash and weak backwash
7
Q
Give me 6 features of destructive waves
A
High energy and frequency, steep gradient waves, tall waves with short wavelength, weak swash, strong backwash (beach erosion)
8
Q
Name 3 types of soft engineering
A
Coastal zoning (marsh creation)
Dune regeneration
Beach nourishment
9
Q
When would you use coastal zoning?
A
When the land has not already been developed as the land behind it has no economic value, meaning no need for expenses on coastal management
10
Q
What is the role of beach nourishment
A
To replace the beach or cliff material that has been removed by erosion or LSD. It increases the size of beaches meaning that when waves come up the beach, they have no energy left to erode.
11
Q
What is the role of dune regenerations ?
A
Involves creating new sand dunes or stabilising existing dunes so that they can act as a barrier between the land and the sea, absorbing storm and wave energy.
12
Q
Give 4 advantages of beach nourishment
A
Sustainable, tourists, cheap, doesn’t change the natural environment
13
Q
4 disadvantages of beach nourishment
A
High maintenance
Have to close beach
Disturb marine life
14
Q
3 advantages of dune regeneration
A
Sustainable
Cheap
Creates habitats
15
Q
A disadvantage of dune regeneration
A
Can be wiped out in storm surges or strong winds
16
Q
3 advantages of coastal zoning
A
Costs nothing
Looks nice
Good environment
17
Q
3 disadvantages of coastal zoning
A
Erosion continues
Cant use the land
Individual complaints - someone’s house may have to go
18
Q
Why is soft engineering sustainable when hard engineering isn’t?
A
Although hard engineering by outcome is stopping erosion, it is not sustainable because you can’t physically stop erosion. Yet soft engineering reduces the impact of erosion
19
Q
Why do spring and neap tide occur?
A
Spring tide happens when the gravitational pull from both the sun and the moon is aligned and therefore there is a compensatory bulge and tide is at its highest. Neap tide happens when the sun and the moon form a right angle which means there is less gravitational pull and there is the lowest tide range.
20
Q
When does a storm surge occur?
A
When the tide is unusually high (higher than spring tide) due to storm conditions when the wind is so powerful
21
Q
What is our case study for mass movement
A
Holbeck hall
22
Q
What is sub-aerial weathering?
A
Weathering that takes place lower down the cliff, creating weak points for erosion to compress into the cliff and erode it more efficiently
23
Q
What are the 3 sections in long profile of a beach
A
Nearshore, foreshore, backstory
24
Q
Name the features of the beach in order from the backshore to the nearshore
A
Storm beach, berms, cusps, runnels, ripples.
25
What is a spit
A long narrow ridge of sand an shingle which is projected into the sea from the coastline. Behind it salt marshes can form.
26
What is our case study of a spit?
Spurn head at Holderness Coast
27
What is stopping the spit from continually growing until it reaches another headland or island?
A river estuary (current)
28
What is a salt marsh?
A low energy zone formed behind a spit, where deposition occurs.
29
How is a bar formed?
The same way as a spit, except it continues the process until it joins another headland. Or it can be formed by an offshore glacial deposit, where roll-over has caused material to be transported landward.
30
How is a tombolo formed?
Same as a spit, it just continues until it reaches an island.
31
Name the 4 types of transportation
Traction, saltation, suspension, solution
32
What are the new dunes called at the front of the beach?
Embryo / foredunes
33
What are the 4 factors needed to form a sand dune?
Sand
Wind
Plants
An obstacle to trap the sand
34
Why is the biggest dune called?
Yellow dune
35
Give 1 marine, atmospheric and human imput of the coastal system
Wave, tides or salt spray
Air pressure, sun, precipitation, wind speed
Pollution, recreation, settlement, defences
36
What is isostatic change?
The rise of land masses that were previously covered by ice sheets during the last ice age. This causes some land to be rising whilst others sinking. Sea level rise is localised and dependent on the change in the land
37
What is eustatic change?
Worldwide changes in sea level caused by glacial and interglacial periods.
38
What are the 2 factors that cause eustatic change?
Thermal expansion
| Ice caps melting
39
What is thermal expansion ?
When water expands due to global warming
40
How is a fjord formed?
In mountainous areas, within U shaped valleys that have been carved by abrasion, there would have been a glacier connecting the high cliffs, as they melt, the water as well as the sea fills the valley floor
41
How is a ria formed?
During the last ice age when the sea level was lower. Now as sea levels rise, the valley now cuts below present sea level. After the ice melted etc, the valleys drowned leaving rias.
42
What is our case study for coastal flooding?
Hurricane Katrina in New Orleans
43
What's our example for sea level rise?
The Maldives.
44
Give me examples of hard rock
Limestone or chalk or granite
45
Give an example of soft rock
Clay or Flint
46
Give physical causes of coastal erosion
Destructive waves - much more energy, huge height and steepness which covers more area of the cliff
Spring tide - high tide = bigger tidal range
47
Where are headlands and bays found
Discordant coastlines (alternating layers of hard and soft rock)
48
What processes are involved in headlands and bays?
Erosion and deposition (bays & beaches)
49
What happens when waves refract around the headland
Destructive waves refract around the headland so there is more concentrated energy on the sides of the headland which creates other coastal landforms (crack cave arch etc)
50
Give an example of a stack
Old Harry's rock in the Isle of Purbeck within Dorset
51
Where is a blowhole formed?
In a cave, needs specific conditions to occur & a high energy coastline (destructive waves and storms) also hard rock
52
What processes are needed to form a blowhole?
Erosional - hydraulic action - compressed air
53
Describe the formation of a blow hole
1) Sea moves in land erodes the crack/cave whilst weathering and erosion erodes the roof of the rock when sediment is picked up and a vertical shaft is eroded towards the surface.
2) waves crash into cave and reflect upwards and weathering continues on the top
3) this continues until water breaks through it when the waves crash and a blow hole is formed.
54
Where do wave cut platforms form?
Between neap tide and spring tide
55
Give an example of where a blowhole is found
North Coast of Barbados
56
Give an example of where a wave cut platform is found
Flamborough head
57
What is mass movement?
When the cliff collapses due to gravity
58
Give an example of a mass movement event
Holbeck hall
59
What is sub aerial weathering ?
The breaking down of rock at the top and middle of the cliff due to weathering
60
What processes are involved with sub aerial weathering
Weathering and mass movement
61
Name the 4 types of weathering
Freeze-thaw, exfoliation, biological and chemical
62
What is freeze thaw?
Water gets into cracks in rocks, when it freezes it forces the rock apart. Happens in cold places
63
What is biological weathering
Roots from plants, and animals burrow making cracks in the rocks. This makes rocks break apart
64
What is chemical weathering
Acid rain that falls onto rock and dissolved it making it crumble away
65
Exfoliation weathering
In hot places when rocks get hot in the day and cold at night, it makes the rock break of in layers
66
What is the role of sub aerial weathering in coasts
Breaks down the cliffs and creates weak points for erosion to take place.
67
Where are beaches typically formed?
At a bay
68
What are the 3 sections of a beach
Back shore foreshore and nearshore
69
What is found at the back shore
Larger materials like shingle that are deposited during storm surges
70
What are features of the foreshore?
Between low and high tide. Swash zone
71
What type of wave is found at a beach
Constructive
72
Name 6 features of a beach (like landforms)
Storm beach, berms, cusps, ripples, runnels,
73
What is a storm beach and where is it found?
A noticeable semi-permenant ridge at the backshore found at the level above highest spring tides (shingle)
74
What is a cusp and whee is it found and how is it formed ?
Semi-circular embayments found in the shingle or at the shingle/sand junction. It is formed by a strong Swash which is channelled by the sides of the cusp, which then travels into the centre of the depression which therefore produces a stronger backwash and material is drafted back down the beach from the centre of the cusp.
75
What, where and how is a berm formed
Smaller ridges that develop at the backshore at the mean high tide mark because of deposition. It is built up by successive levels of rides or storms. They are generally created by smaller waves which have less energy so the mateRial is smaller
76
Where, what and how are ripples and runnels formed?
Ripples and runnels are small undulations and depressions in the sand formed at the nearshore, therefore the gradient is low and so depressions in the sand are left as tides go out, carrying water drainage off the beach. Runnels are formed here as there is no infiltration of the sand and so the runnels are left as small puddles on the flat beach .
77
Give an example of a bar
Slapton sands in South Devon
78
An example of a tombolo
Chesil beach in Dorset, southern England
79
What a re the 3 types of transportation
Bedload, suspended load, and dissolved load
80
What are the 2 types of rejuvenation
Isostatic and eustatic change
81
What is isostatic change?
Slow movement of the rise of land mass on a localised scale. Causes either sea level rise or sea level fall .
82
What is eustatic change?
World wide changes in sea level due to glacial and interglacial periods. It is cause by the melting of ice caps and thermal expansion
83
What is a submergent landform ?
When the land is submerged by the water - caused by sea level rise
84
What is a emergent landform?
When sea level falls and land is above the sea level
85
What is a fjord?
A submergent landform featuring a long deep narrow inlet of the sea between two high cliffs. They become drowned as sea levels rise. It is a U shaped Valley. It is formed when by the glacier that carves the U shaped valley by abrasion and the glacier retreats rolling the valley fall with the sea water
86
What is a ria?
A submergent landform formed as the ice caps melt causing sea level to rise and so now the valley cuts below the present sea level. After the ice melted, the valleys drowned leaving rias in hilly areas
87
Name 4 submergent landforms
Fjord, rias, shingle ridge, drowned forest
88
Name the 1 emergent landform
Raised beach
89
Is hard engineering sustainable?
No because you can't physically stop erosion
90
What are groynes and what do they do?
Wooden barriers built at right angles to the beach and are designed to slow down LSD and build up a beach area. This increase the size of the beaches and therefore when the waves come up the beach, they have no energy left to erode
91
What are gabions and what do they do?
Where rocks and boulders are encased in wired mesh. They absorb the energy from the waves.
92
What is a sea wall and what does it do
Build on the inland part of the coast to reduce the effects of strong waves. A modern concrete sea wall is curved to reflect most of the waves energy back to sea. The wall acts as a barrier between the waves and the land to prevent erosion
93
What is rock armour / rip rap and what does it do?
It is made by large rocks being piled/placed at the foot of the cliff (or even dune) to absorb some energy to limit erosion. The large rocks create a barrier between the waves and the land to prevent erosion.
94
What is beach nourishment and what does it do?
It replaces beach or cliff material that has been removed by erosion or LSD. This repairs damage done to the beach and cliff areas. Like groynes, it increases the size of the beach and therefore when the waves come up the beach they have no energy left to erode.
95
What is dune regeneration and how does it work
It involves artificially creating new sand dunes or stabilising existing dunes by fencing to help trap sand or planting marram grass. The dunes act as a barrier between land and sea, absorbing storm and wave energy.
96
What is a revetment and what does it do
A revetment is a sloping feature which breaks up or absorbs the energy of waves while letting water and sediment pass through. It is a cheaper alternative to a sea wall. The sloping wall creates a barrier between the waves and land to limit erosion.
97
Give advantages and disadvantages of sea walls
Advantages - the most effective, and can last a relatively long time (20-30 years) & you can build behind it
Disadvantages - the most expensive (£1 mill per km), constant need for repair so another method is needed as well. It's also unsustainable and ugly
98
Give advantages and disadvantages on revetments
Advantages - relatively cheap, use wood which is more natural and doesn't look as bad, it's also relatively effective
Disadvantages - needs constant maintenance as wood rots, can't use them in tourist places and its unsustainable
99
Advantages and disadvantages of gabions
Advantages - relatively cheap, they're a good support for other hard engineerings
Disadvantages - unsustainable, not visually attractive, danger hazard for children (wires), not as effective as other hard engineerings
100
Advantages and disadvantages of rock armour
Advantages - little environmental impact, extremely effective, easy to manage (add more rocks)
Disadvantages- high maintenance, expensive to get the rocks there, could be dangerous in tourist destinations
101
Advantages and disadvantages of groynes
Advantages - creates a big beach = good for tourists, may get cost back through tourism, wooden = more pleasing & also effective
Disadvantages - creates erosion further down the beach - disrupts sediment cells and could stop the development of a depositional landform
102
Advantages and disadvantages of beach nourishment
Advantages - sustainable, cheap, doesn't change the natural environment, good for tourism
Disadvantages - high maintenance (need to continually top it up), have to close the beach, could be disturbing marine life
103
Advantages and disadvantages of dune regeneration
Advantages- sustainable, cheap and creates habitats
Disadvantages - can be wiped out in storm surges or strong winds
104
Advantages and disadvantages of marsh creation or managed retreat
Advantages - costs nothing, looks nice and it's good for the environment
Disadvantages - erosion proceeds, can't use the land - shortages of houses, individuals - someone's house may have to go
105
What is beach recycling?
Bulldozers dig up sand at East and transfer it to west so that LSD can work its way back over again
106
What is beach re profiling
Changing the gradient of the beach to the best one for absorbing wave energy
107
Give 2 positives and 3 negatives of beach re profiling
+ve - reflects wave energy and looks natural
-ve - during storms, destructive waves drag sediment back down beach meaning that it is more vulnerable to erosion as there is less beach protecting it.
It is noisy and scares wildlife
Needs constant maintenance and re profiling
108
Give 2 advantages and 2 disadvantages of beach recycling
+ve - no material is needed to be dredged from the sea
-beach has an even profile and so is not subject to wave attack
- ve - has to be carried out 3 times a year which is expensive
- Large trucks disturb wildlife and puts off tourists - economic impact
