Coasts Flashcards
(224 cards)
1
Q
Are coastal environments open or closed systems?
A
Open
2
Q
What is dynamic equilibrium?
A
When there is a balance between the inputs and the outputs of the system.
3
Q
What are some inputs into a coastal system? (4)
A
- Energy from waves, wind, tides and sea currents.
- Sediment.
- Geology of coastline.
- Sea level change.
4
Q
What are components of a coastal system?
A
- Erosional landforms and landscapes.
- Depositional landforms and landscapes.
5
Q
What are some outputs of a coastal system? (3)
A
- Dissipation of wave energy.
- Accumulation of sediment above the tidal limit.
- Sediment removed beyond local sediment cells.
6
Q
What are antecedent conditions?
A
The previous conditions.
7
Q
What provides most of the energy in a coastal system?
A
Breaking waves.
8
Q
Do erosional coastlines have more of less energy than depositional coastlines?
A
More energy.
9
Q
What is negative feedback and what is an example of it?
A
Negative feedback is when an action leads to something becoming less that it was before; this could be a good or a bad thing.
- A decrease in wave energy could lead to deposition of sediment offshore, further reducing wave energy.
10
Q
What is positive feedback and what is an example of it?
A
Positive feedback is when an action leads to something becoming more than it was before; this could be a good or bad thing.
- An increase in wave energy could scour the seabed, deepening the water and allowing more energy to enter the location.
11
Q
What is steady state equilibrium?
A
A situation where variations in energy and the morphological response do not deviate too far from the long-term average.
12
Q
What is meta-stable equilibrium?
A
This exists when an environment switches from two or more states of equilibrium however usually will go back to the normal state of equilibrium.
13
Q
What is the backshore?
A
The backshore is the area between the high water mark and the landward limit of marine activity. Changes normally take place here only during storm activity.
14
Q
What is the foreshore?
A
The foreshore is the area lying between the high water mark and the low water mark. Is it the most important zone for marine processes in times that are not influenced by storm activity.
15
Q
What is the inshore?
A
The inshore is the area between the low water mark and the point where the waves cease to have any influence on the land beneath them.
16
Q
What is the offshore?
A
The offshore is the area beyond the point where waves cease to impact upon the seabed and in which activity is limited to deposition of sediments.
17
Q
What is the nearshore and what does it consist of?
A
The nearshore is the area extending seaward from the high water mark to the area where waves begin to break.
It includes the swash zone, surf zone and breaker zone.
18
Q
What is the swash zone?
A
The swash zone is the area where a turbulent layer of water washes up the beach following the breaking of a wave.
19
Q
What is the surf zone?
A
The surf zone is the area between the point where waves break, forming a foamy, bubbly surface, and where the waves then move up the beach as swash in the swash zone.
20
Q
What is the breaker zone?
A
The breaker zone is the area where waves approaching the coastline begin to break, usually where the water depth is 5 to 10m.
21
Q
How are cliffs and wave cut platforms formed?
A
- Cliffs form as the sea erodes the land. Over time, cliffs retreat due to the action of the waves and weathering.
- Weathering and wave erosion cause a notch to form at the HWM. This eventually develops into a cave.
- Rock above the cave becomes unstable and collapses.
- Wave cut platforms are flat surfaces left behind when a cliff is eroded.
22
Q
How are simple spits formed?
A
- Longshore drift deposits material across the river mouth, leaving a bank of sand and shingle sticking into the sea.
- A stright spit that grows roughly parallel to the coast is a simple spit.
23
Q
What is an example of a simple spit?
A
Spurn Point
24
Q
How are compound spits formed?
A
- A recurved end may form due to changes in wind and wave direction.
- Several recurved ends may be abandoned. A spit that has multiple recurved ends from several periods of growth are compound spits.
25
How are sand dunes formed?
- Sand dunes are formed when sand deposited by longshore drift is moved up the beach by wind.
- Sand trapped by driftwood or berms is colonised by plants and grasses. The vegetation stabilises the sand and encourages more sand to accumulate there, forming embryo dunes.
- Over time, the oldest dunes migrate inland as newer embryo dunes are formed. These mature dunes can reach up to heights of up to 10m
26
Name an example of a sand dune.
Gibraltar Point
27
How are barrier beaches formed?
A barrier beach is usually formed as an extension to a spit.
Longshore drift moves sediment along the coastline until there is a change in the coastline.
A spit develops, usually in a bay and
once the spit develops across the whole bay, a barrier beach forms.
Barrier beaches are unlikely to form in estuaries as the outcoming force of freshwater will always keep part of the estuary clear.
Colonisation by vegetation can stabilise the barrier beach and trap further sediment keeping the barrier beach above sea even at high tide.
Depending upon the climate the landward side may be colonised by mangroves in the still lagoon, which adds further stability.
28
Where can barrier islands be found?
Horn Island, Mississippi
29
How are caves, arches and stacks formed?
- Some landforms are found in cliffs- cliff profile features.
- Weak areas in rock such as joints are eroded to form caves.
- Caves on opposite sides of a narrow headland may eventually join up to form an arch.
- When an arch collapses, it forms a stack.
30
How are beaches formed?
- Beaches form when constructive waves deposit sediment on the shore- these are a store.
- Shingle beaches are steep and narrow. They are made up of larger particles, which pile up at steep angles.
- Sand beaches, formed from smaller particles, are wide and fat.
31
How are bars and tombolos made?
- Bars are formed when a spit joins two headlands together. This can occur across a bay or river mouth.
- A lagoon forms behind the bar.
- Bars can also form off the coast when material moves towards the coast. These may remain partly submerged and are called offshore bars.
- A bar that connect the shore to an island is called a tombolo.
32
Name an example of a bar.
Slapton sands bar, Devon
33
Name an example of a place joined by a tombolo.
St Ninian's Isle, Shetland Islands
34
What is the fastest eroding coastline in Europe?
Holderness
35
How long is the Holderness Coastline?
61km
36
What are most of the cliffs at the Holderness Coastline made of?
Glacial till
37
What is the rate of erosion at Great Cowden (Holderness)?
4m/ year
38
What type of mass movement is Holderness prone to?
Slumping when it is wet.
Water makes clay heavier and acts as a lubricant between particles, which makes it unstable.
39
What direction is longshore drift on the Holderness Coastline?
Southwards
40
Where is sediment deposited on the Holderness coastline?
Where the ocean current meets the outflow of the Humber River.
41
Example of a headland at the Holderness Coastline
Flamborough Head
42
Where are slumping cliffs found at the Holderness Coastline?
Around Atwick Sands
43
Example of a spit at the Holderness Coastline
Spurn Point
44
Where can sand dunes be found on the Holderness Coastline?
Around Spurn Point
45
How many villages have been lost over the past 1000 years at the Holderness Coastline?
30
46
How much has the Holderness coastline retreated over the past 2000 years?
4km
47
Name an environmental consequence of erosion at the Holderness Coastline?
Loss of Sites of Specific Scientific Interest (SSSIs) for example the lagoons near Easington provide habitats for birds.
48
Name an economic consequence of erosion at the Holderness Coastline?
Loss of infrastructure for example the gas terminal at Easington is only 25m from the cliff edge.
49
Name an social consequence of erosion at the Holderness Coastline?
Loss of settlements and livelihoods for example the village of Skipsea is at risk and 80000m2 of good quality farmland is lost each year on the Holderness coast, which has a huge effect on farmers' livelihoods.
50
How much of the Holderness coast is protected by hard engineering?
11.4 km
51
What is Bridlington protected by?
4.7km long sea wall and timber groynes
52
What coastal defences are at Hornsea?
Concrete sea wall, timber groynes and riprap.
53
What coastal defences were built at Mappleton in 1991?
Two rock groynes and a 500m long revetment.
They cost £2 million and were built to protect the village and the B1242 coastal road.
54
What has a landowner is Skipsea used to protect his caravan park?
Gabions
55
What is Easington gas terminal protected by?
Revetment
56
Why has the Mappleton scheme negatively effected other areas?
Groynes have caused beaches to be sediment starved and so the cliffs southward of Mappleton are experiencing increased erosion.
Cowden Farm is at risk of falling into the sea.
57
What is a negative of bays being formed due to protection of local areas along the Holderness?
As bays develop the wave pressure on headlands will increase and eventually the cost of maintaining the sea defences may become too high.
58
Are existing schemes at the Holderness Coastline sustainable?
No
59
Who developed the ICZM for the Holderness Coastline?
East Riding of Yorkshire Council
60
What does the ICZM manage?
Complete sections of the coast as a whole
61
What was the ICZM used to develop?
The Flamborough Head to Gibraltar Point Shoreline Management Plan
62
What does the SMP for Holderness for the next 50 years suggest?
Holding the line at some settlements but doing nothing at less populated stretches.
63
Would managed realignment be more sustainable on the Holderness coastline?
Yes, however there are issues surrounding how much compensation businesses would get for relocating.
Relocating also isn't always possible.
64
In 1995, what did the Holderness Borough Council decide to do?
Stop trying to protect Spurn Point from erosion and overwashing.
This saves money and allows the spit to function naturally but overwashing may damage marsh environments behind the spit.
A coastguard station on the spit may be at risk.
65
What does the SMP suggest in terms of Easington Gas Terminal?
To maintain the rock revetments for as long as the gas terminal is running.
The defences only span 1km meaning the village of Easington (pop 700) is not protected.
The defences may also increase erosion as SSSIs to the south.
66
Name an estuarine environment.
The Severn Estuary
67
How are waves created?
- As wind hits the water, ripples form. Then, wind gets an even better grip and continues to push the ripples until they grow into larger waves.
68
What does wind energy depend on?
Speed, distance and time
69
Features of constructive waves.
- Low wave frequency
- Low energy
- Strong swash
- Weak backwash
70
Features of destructuve waves.
- High wave frequency
- Weak swash
- High energy
- Strong backwash
- Small wavelength
71
What happens when a wave approaches a headland?
- They begin to slow due to the shallower water around the headland.
- However the waves which remain in deeper water continue to move faster towards the bay as they are unaffected by friction.
72
What is the highest and lowest point of a wave?
Trough- lowest
Crest- highest
73
What are rip tides?
- Strong narrow currents that flow seaward through the surf zone.
- Run along the surface of the water.
- Formed by a beaches topography.
- Beaches with breaking waves experience rip currents.
74
What are tides?
The periodic rise and fall in the level of the sea.
75
What causes tides?
The effect of gravity from the moon and the sun acting upon the rotating earth.
Ocean surfaces lift where the Earth's gravity is slightly neutralised.
76
What is the ebb?
The tidal phase where the water level is falling.
77
What is the flood?
The tidal phase where the water is rising.
78
What is the tidal range?
The vertical difference in heighyt between consecutive high and low waters.
79
What causes a spring tide?
When the sun, moon and earth are in alignment.
80
What is a spring tide?
High tides are a little higher and low tides are a little lower than average.
81
What causes a neap tide?
When the moon faces the earth at a right angle to the sun so the gravitational force of the moon and sun work against each other.
82
What is a neap tide?
High tides are a little lower and low tides are a little higher than average.
83
What affects tides on a local scale?
Wind and weather patterns.
84
What are ocean currents?
The movement of water from one location to another.
85
What three factors drive ocean currents?
- Rise and fall of tides
- Wind
-Thermohaline circulation
86
How do currents affect the Earth's climate?
They drive water from the equator and cold water from the poles around the Earth.
87
Name an area which uses tides to generate energy
Swansea Bay, Wales
88
Name a high energy coastline.
Portuguese west coast
89
Why does the portuguese west coast have a long fetch?
Fetch spans from northern tip of Brazil to Portuguese west coast.
Waves are generated along the fetch and are driven to the west coast due to the Gulf Stream.
The gulf steam divides into two- the North Atlantic Drift and Canary Current.
90
What type of tidal range does the Portuguese coast have?
Meso-tidal
91
What is the tidal range of the Portuguese coast?
2-4 metres
92
How does wind action cause high energy waves on the Portuguese coast?
The wind travel a long distance causing destructive waves with a high crest.
The waves produce longshore movement as they strike at an angle due to the Canary Current's impact- accelerating the removal of material.
93
Lithology of the Portuguese coast.
- Composed of high cliffs which are easily undercut
- Discordant coastline
94
Name a headland on the Portuguese coast.
Cape St Vincent
95
Where are wave cut platforms located on the Portuguese coast?
Cape Mondego
96
Name a low energy coastline.
Chesapeake Bay, East Coast USA
97
What is the average depth of Chesapeake Bay?
9m- these will reduce wave energy as there is increased friction.
98
Why is Chesapeake Bay protected from high energy waves?
Many barrier islands lay in the bay itself.
Land encloses the bay area.
99
What is the average tidal range of Chesapeake Bay?
1.7m
Increased tidal range of the eastern side of the bay.
100
Name an example of a sediment cell.
Cape Naturaliste to Moore River, Western Australia
101
What is a storm surge?
A change in sea level caused by a storm.
Can lead to extensive flooding.
102
Why do we have storm surges in the UK?
The North Sea is open to the north and shut off from the south, which traps the surge off, causing flooding on the east coast.
103
When were the two storm surges in the UK?
1953 and December 2013
104
What caused the 2013 storm surge?
- Low air pressure
- 140 mph winds in Scotland
- High spring tide
105
Effects of 2013 storm surge.
- 7 clifftop homes in Hemsby were destroyed
- 2 people died
- 100 homes in Whitby flooded
- 1000s of Scottish homes had no electricity
106
What caused the 1953 storm surge?
- Low wind pressure
- High spring tide
- Severe European windstorm
107
Effects of 1953 storm surge.
- More than 300 deaths
- 30000 people were evacuated
- 24500 homes were damaged
108
Name the six types of mass movement.
Rockfall
Landslides
Runoff
Mudflows
Slumping
Soil Creep
109
What are rockfalls?
- Very fast dry movements
- Triggers include earthquakes, heavy rain and eruptions or traffic vibrations
- Freeze thaw weathering can impact
110
What are landslides?
- Dry movement prompted by water
- Relatively fast
- Undercutting by the sea and heavy rain are triggers
- Climate change and traffic vibrations are anthropogenic influences
111
What is runoff?
- When heavy rain washes material from the surface of a cliff over the edge and down onto the shore.
112
What are mudflows?
- Wet movement
- Relatively fast but speed slows
- Common on muds and clays
- Forest fires can be a cause.
113
What is slumping?
- Fairly wet and relatively fast
- Material does not travel far
- Usually on unconsolidated rock such as coastal mud and clay
- Triggers include ash fall and snow melt and building on clifftops and climate change
114
What is soil creep?
The mass effect of individual particles taking a downwards trajectory over time from a cliff face as a result of wave impact, rain splash, weathering and gravity.
115
What is wetting and drying?
Rock in the intertidal zone may alternate between being wet and being dry. Some rocks, such as shale, expand when they are wet and contract when being dry, and this can contribute to tiny fissures developing and the rock fragmenting.
116
What is exfoliation?
Dry rock in the sunshine may absorb considerable heat, then be cooled rapidly by contact with the much colder sea. Repeated expansion and contraction may lead to the outer layers of rock fracturing.
117
What is crystalisation?
The high salt content of the seawater can lead to the growth of salt crystals within rock under drier conditions. These can exert pressure within small joints and, over time, cause the rock to lose integrity.
118
What is freeze-thaw activity?
Rainwater penetrates joints in exposed rock and if night temperatures drop below freezing, the resulting conversion to ice expands and exerts pressure within the rock, enlarging the fissure.
119
Examples of biological weathering.
- The roots of surface plants on cliff tops can create and expand tiny fissures. Subsurface seaweed such as bladderwrack attached to rocks can weaken and detach then as it sways in the currents of storm conditions.
- Surface animals such as sand martins and puffins may excavate nesting burrows in cliff faces. Subsurface marine creatures such as the piddock drill holes in rock and limpets create a home indentation in their base rock to which they return after grazing.
120
What is carbonation?
Coastlines composed of chalk or limestone may be dissolved by acidic rainwater or seawater. The rain/sea absorbs carbon dioxide from the atmosphere, creating a weak carbonic acid. This can convert solid calcium carbonate to soluble calcium bicarbonate and the rock dissolves.
121
What is oxidation?
Rocks containing iron compounds experience oxidation of the iron into a ferric state (rusting) when oxygen and water are readily available from air or sea, This can lead to disintegration.
122
What is hydration?
Occurs when water is absorbed by minerals in the rock, creating crystals which exert pressure on the surrounding rock, eventually causing it to crumble.
123
What is hydrolysis?
Occurs when water reacts with minerals in the rock causing the chemical composition of the rock to change and become more unstable. This reaction makes the rock more susceptible to decomposition.
124
What is hydraulic action?
When waves break against a rock face with joints facing the wave, air inside the joints is highly compressed. This leads to wedging, as the compressed air forces fractures further apart. As the wave recedes, the air expands with a forceful release of pressure. The changing pressure inside the joints’ water content leads to cavitation.
125
What is cavitation?
The violent effervescence of air bubbles coming out of the solution and the pressure drops. The resultant shockwaves can enlarge rock fractures and fragment the cliff.
126
What is corrasion/abrasion?
The launching of rock fragments and pebbles against cliffs by waves during high-energy sea conditions can break off pieces of solid cliff and weaken rock structure.
127
What is quarrying?
Destructive waves in storm conditions can plunge heavy hydraulic pressure on cliff faces. The vibration of the cliff structure can dislodge bits of rock to the point of undercutting the base of cliffs.
128
What is solution?
Some rock, such as chalk and limestone, is readily soluble and dissolved rock is removed in solution rather than disintegrating into fine particles.
129
What is attrition?
This is the smoothing and reduction of angular rock fragments into pebbles, shingle and eventually sand particles. This occurs due to friction as particles are rolled over each other by the continuous action of waves and currents.
130
What is suspension?
Small particles are kept in motion by even quite light currents and turbulence.
131
What is saltation?
Shingle and pebbles may be bounced along the seabed under higher-energy waves and current conditions; the added buoyancy of being submerged in seawater means they travel in a series of hops.
132
What is traction?
Larger rocks may be dragged and sometimes rolled along the seabed, usually in high-energy (storm) conditions.
133
What is a SMP?
Shoreline management plan
134
How many sediement cells are there in England and Wales?
11
135
Who recommends a SMP for all sections of coastline in England and Wales?
Defra
136
What are the 4 options in a SMP?
1. Hold the line
2. Advance the line
3. Managed retreat
4. Do nothing
137
What is an ICZM?
Integrated coastal zone management
138
What does an ICZM do?
Manage complete sections of a coastline as a whole to stop one area being protected and another zone eroded.
139
What is soft engineering?
Coastal management using natural sustainable materials
140
Why would soft engineering be chosen?
It's cheaper, sustainable and looks less artificial
141
What is beach replenishment?
Sand being replaced along a beach
142
What are the advantages and disadvantages of beach replenishment?
+ Effective at dispersing energy
+ Does not look artificial
- Expensive as continuously carried out
143
What is managed retreat?
Allowing nearby land to flood
144
What are the advantages and disadvantages of managed retreat?
+ Habitats can form
+ Fairly cheap
- Causes conflict
145
What is cliff regrading and drainage?
Removing excess water to prevent landslides by reducing the angle
146
What are the advantages and disadvantages of cliff regrading and drainage?
+ Cheap
+ Effective on clay
- Can dry cliffs out which can cause them to collapse
- Some homes may be demolished
147
What is dune stabilisation?
Planting of marram grass on sand dunes
148
What are the advantages and disadvantages of dune stabilisation?
+ Natural coastal environment
+ Cheap
- Time consuming
- May be eroded if people ignore signs and walk on sand dunes
149
Where is the Jurassic Coast?
Dorset and East Devon
150
How many littoral cells does the Jurassic Coast stretch across?
2
151
Where is managed realignment taking place at along the Jurassic Coast?
Axe and Exe Valleys
152
Where is holding the line taking place along the Jurassic Coast?
Chiswell
153
Name a natural defence on the Jurassic Coast.
Chesil Beach (a barrier beach)
154
Why do we manage coastal areas?
- To stop the effect of coastal erosion on settlements
- To stop the effect on economic centres such as London
- To protect SSSIs such as mangroves, sand dunes (Gibraltar Point) and coral
155
What is hard engineering?
Coastal defences which are manually made and are artificial structures.
156
What is a sea wall and its cost?
A concrete barrier which decreases wave energy.
£6,000 per metre
157
What are the advantages and disadvantages of sea walls?
+ Provide a promenade
+ Protects the base of cliffs
- Can erode
- Expensive
158
What is rock armour and its cost?
Made from granite or hard rocks to absorb wave energy
£4,000 per metre
159
What are the advantages and disadvantages of rock armour?
+ Cheaper than sea walls
+ Easy to maintain
- Different rock type to local areas so may look unnatural
160
What are groynes and their cost?
Wooden fences or rock walls built out into the sea to prevent longshore drift
£1,000 per metre
161
What are the advantages and disadvantages of groynes?
+ Builds a beach which can encourage tourism
- Can make settlements 'sediment starved'
162
What are gabions and their cost?
Rocks which are placed in mesh cages in areas affected by erosion
£100 per metre
163
What are the advantages and disadvantages of gabions?
+ Absorb wave energy
+ Cheap
- Not very strong
- Look unnatural
164
What are revetments and their cost?
Sloping concrete or wooden defences facing the sea
£4,500 per metre
165
What are the advantages and disadvantages of revetments?
+ Absorb wave energy
- Expensive
- Don't give total protection for cliffs
166
What is eustatic sea level change?
Global, absolute sea level change.
167
What causes eustatic sea level change?
Anthropogenic climate change caused by burning fossil fuels which causes the enhanced greenhouse effect.
168
What can cause eustatic sea level change?
Melting of the cryosphere and thermal expansion.
169
What is isostatic sea level change?
Local, relative sea level change.
170
What causes isostatic sea level change?
Melting ice sheets leading to isostatic rebound of the land.
171
Name an example of a place experiencing isostatic sea level change.
Arran in NW Scotland- Raised beaches.
172
What is a ria?
A submerged river valley, which are sheltered, winding inlets.
For example, the Loe was a ria before a bar blocked it across its mouth.
173
What is a fjord?
A submerged glacial valley which are deep, long, narrow inlets with steep and often straight sides.
For example the Sogne Fjord is 100km long and the mouth is a shallow seaward entrance known as a threshold.
174
Features of a ria.
V shaped valley
Interlocking spurs
175
Features of a fjord.
U shaped valley
Truncated spurs
Hanging valley
Glacial trough
176
Give an example of a positive feedback loop involving sea level change.
Polar ice caps melt thereofre less albedo effect
Ice has high albedo reflecting solar radiation back to space
Melt ice leads to more sea/grass/woodland and tundra which have a low albedo causing increased temperatures and more melting.
177
What are raised beaches?
Areas of former wave-cut platforms and their beaches which are at a level higher than the present sea level
178
What is a ria coast?
Landform of submergence
In upland coastal regions where the mountains run at right angles to the sea
A rise in sea level submerges or drowns the lower parts of the valleys to form long, naroow branching inlets separated by narrow headlands
Typical to the atlantic type of coast
179
What is a fjord coast?
Submerged U shaped glacial trough
Steep walls with tributary branches joining the main inlet at right angles
Deep inland and shallower seaward
Confined to higher altitudes which had glaciers- for example Norway and Alaska
180
What is a dalmatian coast?
Submergence of coastlines produce long, narrow inlets with a chain of islands parallel to the coast
Typical of the pacific coast
181
What is an estuarine coast?
Landform of submergence
The mouths of rivers are drowned so that funnel-shaped estuaries are formed
182
What is an uplifted lowland coast?
Landform of emergence
The uplift of part of the continental shelf produces a smooth, gently sloping coastal lowland
Offshore waters are shallow with lagoons and mudflats
Where emergence deposits are sandy; beaches and marine dunes form
An example is eastern Sweden
183
What is an emergent upland coast?
Landform of emergence
Faulting and earth movement may thrust up coastal plateau so whole region is raised with emergent features
Raised beach is the most promenant feature which is beyond the reach of waves
Emergent upland coast is quite straight with steep cliffs and deeper offshore water
Little potential for good port sites
An example is the western coast of the Deccan, India
184
Where is Canvey Island?
A low-lying area on the north side of the Thames Estuary
185
How far above average sea level is Canvey Island?
1m
186
How high are the sea walls at Canvey Island?
6m
187
Which part of Canvey Island is the most populated?
Eastern side
Western side is mostly marshland
Southern side there is a large oil facility
188
What is causing the riseing of sea level at Canvey Island?
Isostatic rebound of the British isles.
189
How much is Canvey Island 'depressing' by per year?
1.5 mm
190
By 2100 what will the isostatic submergence of Canvey Island be?
12 cm
191
How much is eustatic sea level change rising sea level at Canvey Island per year?
3mm
192
What is the plan called in Canvey Island to protect the 40,000 people?
TE2100
193
What adaption strategies are in place at Canvey Island?
Improving current defences
Community strategies such as safe havens on the highest land.
Single storey buildings must have escape or community refuge plans. If not they should be replaced by multi storey buildings.
Western marshlands may have to be prepared for managed retreat if other strategies haven't been successful by 2050
194
What temporal changes are associated with each type of sea level change?
(Time it takes for the change to occur)
Tectonic - short term
Isostatic- medium term
Eustatic- short, medium and long term
195
An example of a short term change due to tectonic factors.
Over 200 miles of the eastern coastline of Honshu, northern Japan, dropped by 0.6m, as a result of the Tohoku earthquake of 2011.
196
What is tectonic sea level change?
Local changes caused by tectonic processes.
This can either be uplift or downthrust.
197
Social impacts of sea level rise in Venice.
Sirens have been installed to make people aware of the high sea levels and flooding.
The population of Venice decreased from 184,000 inhabitants in 1950 to less than 90,000 at the beginning of the 1990s; at present the resident population is reduced to 70,000 inhabitants as people find it difficult and annoying to live around the frequent floods.
For now the Consorzio uses stop-gap measures such as raising sidewalks and extending temporary flood walkways to protect the city.
198
Economic inpacts of sea level rise in Venice.
A 30cm rise in sea levels would close the floodgates for around 70 hours per month, and a 50cm rise would close the floodgates for 166 hours per month. This would obstruct shipping and cruise vessels. This would slow the economy of the city and ships would move to cities than are less more likely to dock at.
The MOSE floodgate system cost 3.2 billion Italian Lira and 1989 (aroud 1.6 billion euros). In november 2019 the project was 94% done.
199
Envrionmental impacts of sea level rise in Venice.
The local government opposes the moving of mud to prevent the release of toxic chemicals into the water supply
A large port has been proposed outside the lagoon for cruise ships to limit the environmental impacts tourism has on the lagoon.
200
Political impacts of sea level rise in Venice.
There have been few attempts by the Italian government to mitigate sea level rise
The MOSE project was linked to large amounts of financial misconduct which almost doubled the cost of the project, and the project still doesn’t meet all the requirements
The Italian government passed a special law in 1973 in an attempt to turn back the environmental devastation of the city’s lagoons.
Italy passed a law preventing cruise ships from coming within 2 miles of the shore unless necessary to prevent the need for dredging (which increases the risk storm surges have on the lagoon)
201
Social impacts of sea level rise in Tuvalu.
Tuvalu could be one of the first nations to be significantly impacted by rising sea levels due to global climate change.
In the center of the island, water can come up out of the coral bedrock, covering up part of the airport and main roads, affecting transport and infrastructure.
Flooding of homes
In november 2001 young families began to migrate - nearly 3000 people have already left.
202
Environmental impacts of sea level rise in Tuvalu.
The islands are experiencing more extensive tropical storms in the wet season (October to March), causing damage to infrastructure, farming and livelihoods.
Whilst in the dry season (June to September) increasing droughts in are putting the source of fresh water, rainfall, at risk. In addition, groundwater has become contaminated by salt. This leads to saline pollution affecting crops and fruit trees.
Added to this is the additional problem of sea temperature rise, leading to coral bleaching and impacts on marine life. This is causing depletion of fish stocks, particularly tuna, on which the island economy depends.
203
Economic impacts of sea level rise in Tuvalu.
The primary economic activities of the country are subsistence farming and fishing, which are both negatively impacted on by the process of rising sea levels.
Saltwater intrusion into farmland can damage crops as well as income
There is a lack of sufficient funding to invest in climate change solutions
204
Where is the Sundarbans region?
Southwest Bangladesh and east India, on the Delta of the Ganges, Brashmaputra and Meghna rivers on the Bay of Bengal.
205
Name three animal species in the Sundarbans.
Irawadi dolphins
Royal Bengal tigers
white-bellied sea eagles
206
What is part of the largest mangrove forest in the world?
Sundarbans
207
Describe the topography of the Sundarbans
Flat and low-lying
Intersected with braided channels which shift
Khals
Chars
208
What are khals?
Smaller networks of channels (distributaries)
209
What are chars?
Islands made out of unconsolidated particles blown by monsoon winds.
210
Is the Sundarbans in dynamic equilibrium?
yes
211
How many people live in the Sundarbans region?
more than 4 million
212
Economic benefits of the Sundarbans.
Flat, fertile land which is ideal for growing crops, mainly rice.
Mangrove forests provide timber for construction, firewood and furniture.
Ecosystem provides fish, crabs, honey and nipa palm leaves which are used for roofing and basket-making.
213
Services provided by the Sundarbans.
Mangroves are a natural defence against flooding.
Protect the area against coastal erosion as mangrove roots bind the soil.
214
What is a mangrove?
A type of forest found in tropical areas.
Trees are adapted to living in salt water and grow on mud flats.
215
8 risks associated with the Sundarbans.
Lack of fresh water.
Deforestation due to growing population.
Flooding can lead to salinisation.
Dangerous animals including tigers.
Lacks of employment and income opportunities.
Risk of sea level ride due to low lying land.
Poor region (only 1/5 have access to mains electricity)- poor communication.
Hard to access and lack of services.
216
Name the three types of responces to risks in the Sundarbans.
Resilience
Mitigation
Adaptation
217
What is resilience?
Being able to cope with the challenges the environemtn presents.
218
Name five attempts to increase the population's resilience in the Sundarbans.
1. Public Health Engineering Department is increasing access to clean water and sanitation.
2. Better roads and bridges are being built (could cause deforestation).
3. Mains electricity being extended and subsidised solar panels in remote regions- easier for flood warnings to reach people.
4. Farming subsidies to increase food security and decrease poverty.
5. Some NGOs are offering training in sustainable farming and fishing methods.
219
What is mitigation?
Reducing the severity of hazards or other problems.
220
Name three mitigation methods in the Sundarbans.
1. 3500km of embankments were built to prevent flooding bit 800km is vulnerable to being breached in storms and tsunamis.
2. Coastal management projects aim to protect mangrove forests and replant deforested areas. However it is hard to prevent illegal forest clearance.
3. Attemps to mitigate the impact of extreme events such as cyclones. NGOs have provided funding of cyclone shelters and early warning systems but many do not have transport to evacuate.
221
What is adaptation?
Adjusting behaviour to fit the environment.
222
Name four attempts to adapt behaviour in the Sundarbans.
1. In some areas salt resistant rice is being grown to help residents cope with flooding and sea level rise.
2. Projects to increase tourism however if not managed properly could lead to environmental damage.
3. People can build houses on stilts however some infrastructure such as roads cannot be easily protected.
4. Sustainable adaptation such as non-intensive farming practices and ectourism will protect the environment for future generations.
223
What is the difference between barrier beaches and bars?
Offshore bars are largely submarine features while barrier islands are usually above high tide and contain sand dune formations.
224
What nation is planning to become the first 'digital nation'? Why?
Tuvalu, to try and preserve itself through a digital verion online and in the metaverse.
