Coasts Flashcards
1
Q
What is positive feedback
A
Something that causes a system to go out of control
2
Q
What is negative feedback
A
Something that brings the system back to normality
3
Q
What happened in Hallsands
A
- Houses were close to the beach and ocean
- Company dredged/moved the shingle from the beach.
- Shingle protected the beach from erosion.
- Erosion caused the houses to get destroyed.
4
Q
How many high and low tides are there every 24 hours
A
2 high, 2 low
5
Q
How are tides formed
A
Tides are formed by equal attraction of the earth and the moon creates a high tide on the right side of the moon.
6
Q
What 3 things does energy acquired by waves depend upon
A
- ) Strength of the wind.
- ) The length of time it is blowing.
- ) Distance over which it blows (fetch.)
7
Q
What happens when waves approach irregular coastline
A
They refract
8
Q
What is lithology
A
How vulnerable a rock is against water due to its chemical composition
9
Q
What is plant succession
A
The sequence of vegetation changes which occur as plants establish themselves in an environment
10
Q
What is Zonation
A
The geographical expression of plant succession, with older and more diverse plant communities located at increasing distance from the shore .
11
Q
What is eustatic change
A
rising sea level
12
Q
What is isostatic change
A
uplift of landmass
13
Q
What are the 3 A01 parts of SEE-SAW for 20 mark question
A
- Scale
- Explanation
- Examples
14
Q
What are the 3 A02 parts of SEE-SAW for 20 mark question
A
- Seeing Links
- Analysis and evaluation
- Weighted conclusion
15
Q
How many marks is A01 worth
A
10
16
Q
How many marks is A02 worth
A
10
17
Q
What are the 4 options of coastal management
A
- )Hold the line
- ) Advance the line
- ) Retreat the line
- )Do nothing
18
Q
What does hold the line mean
A
Maintain existing coastal defences
19
Q
What does retreat the line mean
A
build no coastal defences, move people away from the coast
20
Q
What does advance the line mean
A
Build new coastal defences further out to sea than the existing line of defence
21
Q
Wat does do nothing mean
A
Build no coastal defences at all, deal with erosion and flooding as it happens
22
Q
What is the aim of coastal management
A
To protect homes, businesses and the environment from erosion and flooding.
23
Q
How can we choose which places are protected
A
cost - benefit analysis
24
Q
What places are normally more favoured to protect
A
The larger settlements and important industrial sites rather than smaller isolated settlements
25
What is hard engineering
Where the sea is built out of concrete or rocks providing permanent defence. they have a specific purpose.
26
Why are sea walls recurved
So they can throw back the wave, preventing erosion of the coast
27
Why does the facing on a sea wall have to be continuous
As if it wasn't it would be eroded quickly by Hydraulic action
28
What do sea walls create and why is it bad
a strong backwash, bad as it erodes under the wall.
29
Are sea walls expensive
yes
30
How much can sea walls be per metre
£800 to £5000 per metre.
31
What is a recurved sea wall made up of
steel pile and concrete
32
What is rock armour / rip-rap made up of
large boulders piled up along the beach
33
What does rock armour do
the boulders absorb wave energy and so reduce erosion.
34
Is rock armour / rip-rap expensive or cheap and how much per metre
fairly cheap, £300 per metre
35
What are 2 limitations of rock amour
1. ) can shift in storms
| 2. ) Not always visually attractive
36
What are 2 positives of rock armour
1. ) Fairly cheap
| 2. ) Can look relatively natural depending on location
37
What are gabions
rock - filled cages
38
where are gabions usually placed
A wall of gabions is usually placed and built at the foot of cliffs
39
What do Gabions do
- they absorb wave energy and so reduce erosion
| - They allow waves to percolate
40
Are Gabions expensive or inexpensive and how much per square metre
cheap, £11 per square metre
41
3 limitations of Gabions
1. ) Fail relatively quickly, spilling contents if stacked
2. ) move in strong waves
3. ) look ugly
42
What are revetments
slanted structures built at the foot of cliffs
43
What materials are revetments made from
concrete, wood or rocks
44
what is the job of revetments
Waves break against the revetments, which absorb the wave energy and so prevent cliff erosion
45
are revetments expensive or inexpensive to build and how much per metre. are they cheap or expensive to maintain
expensive to build, cost £100 per metre, cheap to maintain
46
3 limitations of revetments
1. ) expensive to build
2. ) they damage foreshore ecosystems
3. )They create a strong backwash which can erode
47
What are Groynes
Fences built at right angles to the coast
48
What do Groynes do
They trap beach material transported by longshore drift. which creates wider beaches, which slow the waves (reducing their energy.) and hence gives greater protection from flooding and erosion
49
Are Groynes expensive or inexpensive and how much per groyne
quite cheap, costs £200,000 per groyne
50
What is a limitation of Groynes
That smaller beaches do not protect the coast as well, leading to greater erosion and flooding
51
What do offshore reefs do
run more or less, parallel to the shore, forcing the waves to break offshore and protect the beach area.
52
Are reef barriers/ breakwaters expensive or inexpensive and how much per metre
Very expensive, £2000 per metre
53
One limitation of offshore reefs
can be damaged in storms
54
What are barrages
they are dams built across river estuaries.
55
What is the main purpose of a barrage
to generate electricity.
56
How do barrages work
Water is trapped behind the dam at high tide, controlled release of water through turbines in the dam at low tide generates electricity.
57
What do Barrages do
- prevent flooding from storm surges.
| - create large freshwater lakes and may be associated with land reclamation
58
Are Barrages expensive or inexpensive
very expensive
59
What are the limitations of Barrages
- Disrupt sediment flow
- Cause increased erosion elsewhere in the estuary.
- Large impact on the natural habitat - loss mudflats and the associated avian population
60
What are 4 disadvantages of hard engineering
1. ) Expensive to build and maintain e.g. sea wall repairs cost £5000/m
2. ) Defence can have serious consequences
3. ) May keep up with sea level rise
4. ) Can sometimes be an Eyesore
61
What is the definition of soft engineering
The uses if natural materials and processes to help protect the coastline.
62
Name the 7 types of soft engineering
1. ) Beach nourishment
2. ) Beach stabilisation
3. )Dune regeneration
4. ) Creating Marshland
5. ) Managed retreat
6. ) Land-use management
7. ) Do nothing
63
What is beach nourishment
The attempt to replace material (sand and shingle) that has been lost through longshore drift.
64
What is a limitation of beach nourishment
imported sediments may have environments and visual drawbacks.
65
What is beach stabilisation
reducing the slope angle and planting vegetation, or by sticking stakes and old tree trunks in the ground to stabilise the sand
66
Why are wider beaches more useful for coastal management
reduce erosion of cliffs etc
67
What is dune regeneration
where sand dunes are created or restored between land and sea, absorbing wave energy and preventing flooding and erosion.
68
What are management strategies to regenerate dunes
1. ) Replanting vulnerable areas with plants.
2. ) Afforestation with conifers
3. ) Selective grazing
4. ) Fencing off areas - restricting access
5. ) Providing boardwalks
6. ) Giving tourists information about potential damage.
69
What does 'creating marshland' mean.
mudflats can be encouraged by planting appropriate vegetation.
70
Why is the vegetation important in 'creating marshland'
vegetation stabilises the sediment, and the stems and the leaves reduce the power of the waves.
71
What does 'creating marshland' reduce
flooding around the area of the marsh
72
What is managed retreat
involves breaching an existing coastal defence and allowing the sea to flood the land behind.
73
What is land use management.
when you address the local people's behaviour and educate them.
74
What's an example of good land use management
caravan parks on the cliff tops can provide an income for the land, but ca be quickly re-sited when the time comes.
75
What are 2 limitations of land use management
1. ) Only works if people are willing to co-operate.
| 2. ) Cannot remedy damage that has already been done.
76
What is the 'do nothing' approach to coastal management.
10's of millions of pounds are spent annually in the uk protecting the coastline, may be cheaper to let nature take it's course and pay compensation to those affected.
77
where do some people think the funds should go instead of coastal management
that the limited funds available for coastal protection should be targeted to a places like this that have significant infrastructural or economic value for large numbers of people.
78
Why is soft engineering more sustainable then hard engineering.
- Hard engineering is often expensive and disrupts natural processes.
- Soft engineering schemes tend to be cheaper and require much less time and money to maintain then hard engineering schemes.
- overall lower environmental impact and economic cost.
79
What is cost-benefit analysis
when the advantages and disadvantages of each option are weighed up, and the cost implications are considered.
80
Why is cost-benefit analysis useful
as it would cause problems elsewhere along the coast and it is not practical to build sea defences around the whole coast of Britain.
81
how much did it cost for the main part of the town in Lyme Regis cost
£33 million.
82
How does a rise in sea level affect coastal management.
more will be needed to protect coastal settlements and developments.
83
What is an SMP
A Shoreline management plan. a written document which identifies the natural processes, human activities and management decisions, written for each distinct coastal management zone which is defined by a sediment cell.
84
What is an ICZM
Integrated coastal management zone. aims to establish sustainable levels of economic and social activity.
85
What does it mean when an ICZM strategy is adopted
An ICZM strategy means that complete sections of the coast are now being managed as a whole, rather then by individuals towns or villages.
86
What do ICZM's and SMP's have in common
they both provide a more holistic overview of the coast, enabling sustainable measures to be implemented based on a fundamental understanding of natural processes and the coastal system.
87
Does Eustatic mean locally or globally
globally
88
Does Isostatic mean globally or locally
locally
89
is the sea level rising/ falling eustatic or isostatic.
Eustatic
90
Is the land rising/falling eustatic or isostatic
Isostatic
91
How is Eustatic sea level change caused
by a change in the volume of the water in the sea, or by a change in shape of the oceans basins
92
The effects of eustatic change are always global but what are the causes
1. ) Tectonic movements - Earth's crust that alter the shape of ocean basins.
2. ) Change in climate - different changes affect sea level in different way
- An increase in temp causes melting of ice sheets, which increases sea level.
- A decrease in temperature causes more precipitation to fall as snow.
93
How is isostatic sea level change caused
by vertical movements of the land relative to the sea.
| Any downward movement of the land causes sea level to ride locally, while uplift of land causes sea level to fall.
94
Why do management strategies for the future must be sustainable
1. ) Rising sea level, more coastal management needed to protect coastal settlements and developments.
2. )Deciding how to manage a coastline is now done in a more integrated way to improve sustainability.
3. )Growing emphasis on the need for more sustainable management strategies. i.e. soft engineering.
4. )The process of trying to come up with a integrated sustainable management plan is called integrated coastal management zone.
95
The effects of isostatic change are always local, but what are the main causes
1. ) Tectonic uplift or depression.
2. ) Compression or decompression of the earths crust due to accumulation or melting of ice sheets.
3. ) Subsidence of land due to shrinkage after abstraction of groundwater.
96
Why is coastal flooding now more likely
due to rising sea levels
97
What is stage 1 of a typical sequence of sea level rise to reflect the advance and retreat of the ice
stage 1
- The climate begins to get colder.
- An increasing amount of precipitation falls as snow.
- Snow turns into glacial ice.
- Snow and ice act as a store for water.
- Hydrological cycle slows down.
- Sea level falls and affects the whole planet, also known as eustatic fall.
98
What is stage 2 of a typical sequence of sea level rise to reflect the advance and retreat of the ice
Stage 2
- The weight of the ice causes the land surface to sink.
- Movement is said to be isostatic.
99
What is stage 3 of a typical sequence of sea level rise to reflect the advance and retreat of the ice
Stage 3
- The climate begins to get warmer.
- Ice masses on the land begin to melt.
- This begins to replenish the main store and sea level rises worldwide(Eustatic).
- Many areas become flooded and the lower parts of the land produce submergent features such as flooded river valleys ( Rias) and flooded glacial valleys (fjords).
100
What is stage 4 of a typical sequence of sea level rise to reflect the advance and retreat of the ice
Stage 4
- Ice is removed from some land areas.
- Begin to move back up to their previous levels (isostatic readjustment).
- If isostatic movement is faster then eustatic, then emergent features are produced such as raised beaches.
- Isostatic recovery affects different places in different ways.
- in some parts of the world it is still taking place as the land continues to adjust to having masses of ice removed.
- The southeast of the UK is sinking whilst the north is rising.
101
What are 3 impacts of sea level rise
1. ) More frequent and more severe coastal flooding.
2. ) Submergence of low lying islands.
3. ) Changes in the coastline.
102
What can happen after these impacts
further impacts, e.g. damage to coastal infrastructure, decrease in tourism, decrease in agriculture, loss of homes.
103
How are rias formed.
where river valleys are partially submerged.
104
What are some features or characteristics of rias.
1. ) have a gentle long and cross profile
| 2. ) wide and deep at their mouth, become narrower and shallower the further inland they reach.
105
How are Fjords formed.
similar to rias but instead drowned glacial valleys.
106
What are some features of Fjords.
- relatively straight and narrow, have very steep sides.
- have a shallow mouth caused by a raised bit of ground caused a threshold.
- very deep further inland.
107
How are Dalmatian coastlines formed.
In areas where valleys lie parallel to the coast, an increase in sea level can form a Dalmatian coastline.
108
what does sea level fall lead to
coastlines in emergence
109
What does sea level rise result in
coastlines in submergence
110
what landforms are created when the sea submerges the existing coastline.
- fjords
- rias
- Dalmatian coastlines.
111
What landforms are created when a new coastline emerges from the sea
- Raised beaches.
| - Relict cliffs.
112
How are raised beaches formed
when the fall in sea level exposes wave cut platforms. and their beaches. over time, beach sediment becomes vegetated and develops into soil.
113
How are relict cliffs formed
When the cliffs above raised beaches are no longer eroded by the sea, and slowly get covered in vegetation.
114
What is i not uncommon to see within relict cliffs.
Wave cut notches, caves, arches and stacks
115
What happens to the raised features on a relict cliff overtime
get weathered away, degrade
116
changes in sea level are the results of what 2 processes
1. ) Increases in the volume of the ocean.
| 2. ) Subsidence of the coastline.
