The Coastal Zone Flashcards
(105 cards)
1
Q
What is weathering?
A
The disintegration/decay of rocks in their original place; at or close to the ground’s surface
2
Q
What are the three different types of weathering?
A
Mechanical, Chemical and Biological
3
Q
What is freeze-thaw weathering?
A
During rainfall, water seeps into pores/cracks in the rock, overnight- temperature drops, water expands as it freezes, cracks widen, over time rock disintegrates
4
Q
What is mass movement?
A
Downhill movement of material under the influence of gravity. (material can slide or slump)
5
Q
What is rockfall?
A
Rapid fall of rock fragments from cliffs of 40 degrees or steeper - often due to freeze-thaw
6
Q
What is a landslide?
A
Blocks of rock slide downhill; chunks of land may stay intact
7
Q
What is mudflow?
A
Saturated soil and weak rock flows down a slope
8
Q
What is rotational slip?
A
A slump of saturated soil and weak rock along a curved surface
9
Q
What is exfoliation?
A
The outer ‘skin’ of rock flakes away due to constant expansion and contraction of the outer layer as the temperature changes- causing it to flake away
10
Q
What is solution (weathering)?
A
The dissolving of minerals in the rock by rainwater
11
Q
What is carbonation (weathering)?
A
Rainwater picks up carbon from the air, so it becomes a weak carbonic acid. Acid reacts with calcium carbonate (chalk and limestone) to form calcium calcium bicarbonate- which then dissolves
12
Q
What are the main source of erosion along the coastline?
A
Waves
13
Q
What is the fetch?
A
The stretch of water which the wind blows over
14
Q
What does a long fetch cause?
A
Larger waves
15
Q
What are the characteristics of constructive waves?
A
Strong swash, weak backwash, so create long slightly sloping beaches
16
Q
What are the characteristics of destructive waves?
A
Weak swash, strong backwash, so erode beaches to become short and steep
17
Q
What is hydraulic action?
A
The sheer force of the waves forcing air into the cracks in the rock
18
Q
What is attrition?
A
Rocks smash together, eroding each-other to become smaller and smoother
19
Q
What is abrasion/corrasion?
A
Pebbles/rocks hit against cliffs, which erodes cliffs- and pebbles- (like sandpaper)
20
Q
What is solution (erosion)?
A
Rocks are dissolved by a chemical reaction with the sea water
21
Q
What are the rock layers called?
A
The rock strata
22
Q
What is a discordant coastline?
A
Bands of soft and hard rock are perpendicular to the sea
23
Q
What is a concordant coastline?
A
Bands of soft and hard rock are parallel to the sea
24
Q
What type of coastline forms headlands and bays?
A
A discordant coastline
25
Which type of rock forms a bay?
Soft rock
26
Which type of rock forms a headland?
Hard rock
27
What is wave refraction?
The bending of the waves around an obstacle, e.g. a headland
28
Once headlands and bays have formed, where is erosion most concentrated?
On the headlands
29
What types of erosion cause wave-cut platforms?
Hydraulic power and abrasion
30
Where is the erosion concentrated on in the formation of a wave-cut platform?
Between the high water mark and the low water mark (the inter-tidal zone)
31
What is formed in the inter-tidal zone?
A wave cut notch, with an overhang above it
32
How can the formation of wave-cut platforms be summed up?
Overhang, collapse, repeats, retreats
33
What land-forms of erosion can be found on a headland?
Crack, cave, arch, stack, stump
34
What is solution (transportation)?
Minerals are dissolved in the seawater and carried in solution, so the load is invisible
35
What is suspension?
Small particles are carried in the water; water appears clouded
36
What is saltation?
Load is bounced along the sea bed, as the current cannot keep it afloat for long periods of time
37
What is traction?
The largest sediment in the load is rolled along the seabed; it is too heavy for the current to carry
38
What is longshore drift?
When material can be seen moving along the beach/coast (in the direction of the prevailing wind at that time)
39
What is deposition?
The build-up of material dropped by the sea
40
When does deposition occur?
When: the coast is sheltered (small waves); waves are constructive; waves have too much material; there is an obstacle (groyne, shipwreck)
41
What are ridges/berms?
Small ridges on a beach, which coincide with high-tide lines and storm tides
42
Where are pebble beaches commonly found?
Where cliffs are being eroded, and where there are high energy waves
43
What are spits?
Long, narrow fingers of sand/shingle that jut out of the coastline, into the sea
44
What is the key process in the formation of spits?
Longshore drift
45
What features often form behind a spit?
Salt marshes or mudflats, as the water is calm and sheltered
46
What is a bar?
A spit which has reconnected to the coast at its other end (distal end), trapping a bay behind it
47
What features form behind a bar?
A lagoon/freshwater lake
48
What type of land-forms are spits and bars?
Land-forms of deposition
49
What is a tombolo?
A ridge that joins land to an island
50
What are the main causes of sea level rise?
ice caps melting- due to global warming
| Thermal expansion of water as temperatures rise (so water takes up more space)- due to global warming
51
What % of islands in the Maldives are less than 1 metre above sea level?
80%
52
What is the total land area of the Maldives?
300 sq km
53
What is the highest point of any of the Maldives islands?
2.4 metres above sea level
54
How much has the population of the Maldives changed in the last hundred years?
Population has quadrupled since 1911
55
What are the main sources of income for the Maldives?
Tourism and Fishing; both of which rely on coral reefs
56
How many tourists does the Maldives receive per year?
500,000
57
If the Maldives were to flood, where would the inhabitants be sent?
Australia, India, and surrounding countries; causing political strains
58
How soon is it possible that the Maldives will be underwater if no action is taken?
The Maldives may be flooded in as little as 50 years
59
What are 3 aims of the Maldives in order to attempt to prevent its flooding?
Become the 1st carbon neutral country by 2020
Replace all vehicles with electric models
Construct a 3 m high sea wall around Male (capital) (would cost £63 million)
60
What is cliff collapse?
When a vertical or near vertical part of the coastline weakens, erodes and falls on the land below
61
What factors contribute to cliff collapse?
Formation of wave cut notches, freeze-thaw weathering ,human activity, rainwater (makes soil heavier)
62
What are the two types of coastal management?
Hard management and soft management
63
What is a sea wall?
Concrete/rock barrier at the foot of a cliff/top of a beach
| Curved face to reflect waves back into the sea
64
What are groynes?
Timber/rock structures built out into the sea from coast
Trap sediment moved by LSD, creates broader beaches
Beach=wave barrier; less waves attack the cliffs
65
What is rip-rap/rock armour?
Piles of large boulders places at the foot of cliffs
Rocks force waves to break & absorb the energy
Rocks brought by boat to coast
66
What is beach nourishment?
Adding sand/shingle to an existing beach, to make it higher/broader
sediment is usually obtained locally, brought onshore by barge
67
What is dune regeneration?
Marram grass planted to stabilise/develop dunes
| Sand dune: natural coastal defence but easily damaged/destroyed (so are usually fenced off when being regenerated)
68
What is marsh creation?
Low lying coastal areas allowed to be flooded by the sea and become salt marshes- an effective barrier to the sea. (example of managed retreat)
69
What is managed retreat?
Allowing land to be eroded naturally. (Usually if land is high flood risk or cliff collapse and is low value/poor quality
70
What are the advantages and disadvantages of sea walls?
+: stops sea, has walkways for people to walk along
| -: ugly/obtrusive, expensive, high maintenance costs
71
What are the positives and negatives of groynes?
+: results in bigger beaches (and tourist potential), useful for fishermen, not too expensive
-: interrupts LSD (encourages erosion elsewhere), unnatural/unattractive
72
What are the positives and negatives of rip-rap?
+: quite cheap, easy to maintain, can provide interest to the coast, used for fishing
-:rocks from other places; expensive to transport, obtrusive, don't fit with local geology
73
What are the positives and negatives of beach nourishment?
+: quite cheap and easy to maintain, blends with existing beach, increases tourist potential; bigger beach
-:constant maintenance
74
What are the positives and negatives of dune regeneration?
+: Maintains natural coast environment, creates wildlife habitats, quite cheap
-: Time-consuming, limited access to tourists, damaged by storms
75
What are the positives and negatives of marsh creation?
+:cheap, habitats for wildlife
| -:land lost, farmers/land-owners need compensation for land
76
What are the positives and negatives of managed retreat?
+: cheap
| -:loss of land, farmers need compensation
77
What are the prices of hard engineering strategies?
sea walls: up to £10 million per sq km, groynes: up to £5 million per km, rip-rap: about £1 to 4 million per km
78
What are the prices of soft engineering strategies?
Beach replenishment: about £3 million per km, Dune regeneration: about £20,000 per km, Marsh creation: about £5,000 to 10,000 per hectare, Managed retreat: £0 (plus compensation)
79
What is an ecosystem?
A community of living organisms in conjunction with non-living components of their environment- interacting as a system
80
What is a habitat?
The natural home or environment of an animal, plant or other organism
81
What are coastal sand dunes?
Accumulations of sand shaped into mounds by the wind, that are found at the back of a beach (above the usual maximum reach of the tide)
82
What type of land-forms are sand dunes?
Dynamic land-forms
83
What is needed for a sand dune to form?
Loose sand, wind/breeze, obstacle (causes sand to build up against it)
84
As you move inland, what happens to the pH levels in the ground?
The pH becomes more acidic (so the pH number becomes lower)
85
What happens to the humus content of the soil?
It increases (from close to 0% up to 10%+)
86
What is the humus content?
The organic component of soil
87
What are the dune names? (from coast to inland)
embryo dune, fore dune, yellow dune, grey dune, mature dune
88
What is the dip in between dunes called?
The dune slack
89
Where is marram grass (mainly) found?
embryo dune, fore dune, yellow dune
90
What plant species are found on/in the grey dune, dune slacks and mature dune?
Grey: sea spurge, heather
Slack: yellow iris, rushes, reeds
Mature: Pine trees, Birch trees
91
Where (on the dunes) is there the smallest amount of animal and plant diversity?
On the most coastal sand dunes (embryo/fore/yellow)- harsh conditions as the dunes are very exposed
92
What animal species are found on/in the grey dune, dune slacks and mature dune?
Grey: adders, sand lizards, butterflies
Slacks: dragonflies, Natterjack toads, water voles
Mature: Sika deer (and many animal species- largest diversity)
93
What is the case study for 'Management/conservation of a coastal environment'?
Studland bay sand dunes
94
Where is Studland bay?
Dorset, Central-South England
95
What other feature does Studland have?
Old Harry rocks
96
In what ways are the Studland bays protected?
Managed by the National Trust, is a NNR (National Nature Reserve), Studland Beach Users Action Group (SBUAG) addresses beach issues
97
What are 4 general issues in sand dune management?
Paths expose sand (meaning it is eroded away by wind), animal habitats easily disturbed, litter/car parking issues due to tourism, fires from BBQs in summer
98
What are specific dune management issues at Studland?
National trust: wants tourists to visit beach (would bring in money; £0.5 mil a year- could be used to protect/conserve) English Nature: wants to limit access to specialist groups; to protect/conserve environment, Tourists: want to pursue many leisure activities
99
What management strategies are being used at Studland?
Boardwalks (protect sand), knoll beach car park, bins, fire beaters (and BBQ ban), fenced areas, dog ban (July-Sept), education centre @ Knoll beach
100
How much rubbish is produced at Studland by tourists?
2 tonnes per week
101
What is the case study for a sustainable coastal management scheme?
The Holderness coast
102
Why does Holderness need coastal management?
It's made of soft rock- glacial till (boulder clay), has no wide sandy beaches to protect it, waves attacking it have a long fetch (high energy), Europe's fastest eroding coastline (about 2 m a year)
103
What strategies are used on the Holderness coastline?
Hornsea: sea wall, rock armour, groynes
Mappleton: rock armour, groynes
Bridlington: sea wall, groynes
Withernsea: sea wall, groynes, rock armour
104
Is the management at Holderness sustainable?
It may not be for points south of the main protection, sediment supply is cut off; so spurn head spit could erode
105
What has the implementation of groynes at Mappleton caused?
'Seaside caravan park' Skipsea losing 10 pitches a year, Sue Earl lost Great Cowden farm (source of income), loss of agricultural land, erosion south of Mappleton has increased from 3 m a year to 30 m
