Coasts Flashcards
1
Q
What are the main inputs and outputs within coastal systems?
A
Marine (waves, tides, currents)
Energy (kinetic, thermal, potential)
Geological
Atmospheric
People
2
Q
What are the four types of erosion?
A
Hydraulic action
Corrosion
Attrition
Abrasion
3
Q
What are the four main types of transportation?
A
Solution
Suspension
Saltation
Traction
4
Q
What happens during the process of longshore drift?
A
Swash carries sediment up the beach, parallel to the prevailing wind.
Backwash carries it back down at right angles to the shoreline.
5
Q
What is a negative feedback loop?
A
When a change to a system is nullified, taking it back towards equilibrium.
6
Q
What is a positive feedback loop?
A
When a change to a system is amplified, taking it away from equilibrium.
7
Q
What is an example of a negative feedback loop?
A
Trampling of sand dunes and damage to marram grass can lead to aeolian erosion causing blowouts.
If left alone surrounding marram grass can release seed, recolonise and lower wind speeds, building the dune back up.
8
Q
What is an example of a positive feedback loop?
A
Vertical growth of marram grass lowering windspeeds and reducing saltation. This leads to further deposition allowing it to grow taller and encourage further lowering of windspeed, accreting the dune.
9
Q
What are the main sources of sediment?
A
Rivers 90%
Onshore sources 5%
Erosion
Offshore sources 5%
Crushed shells of marine organisms
Waves, tides, currents
10
Q
What are the main sources of energy?
A
Winds
Waves
Currents
Tides
11
Q
What are the features of constructive waves?
A
Low wave height
Long wavelength
Low frequency (6-8/min)
Swash > backwash
Depositional
12
Q
What are the features of destructive waves?
A
High wave height
Steep form
High frequency (10-14/min)
Backwash > swash
Erosional
13
Q
How do waves form?
A
Wind blowing across the surface of water (frictional drag).
Circular orbital motion of water particles.
Seabed gets shallower orbits become more elliptical.
Wave height increases, wavelength and velocity decrease.
Water backs up behind the wave until it breaks and surges up the beach.
14
Q
How do tides form?
A
Gravitational pull of the sun or moon changes the water levels of the seas and oceans.
15
Q
What is a spring tide?
A
The Sun and moon align.
Their gravitational forces pull the ocean to them causing high tides.
Lowest possible low tides on opposite side of earth.
Largest possible tidal range.
16
Q
What is a neap tide?
A
Sun and moon perpendicular to each other.
Gravitational forces act against each other.
Overall pull minimised at low tide.
Smallest possible tidal range.
17
Q
What are the characteristics of low energy coasts?
A
Low input
Small, gentle waves
Short fetches, gentle winds
Sloping offshore zones
More deposition than erosion
18
Q
What are the characteristics of high energy coasts?
A
High input
Large, powerful waves
Long fetches, strong winds
Steeply shelving offshore zones
More erosion than deposition
19
Q
What is a sediment budget?
A
A coastal management tool used to analyse and describe the different sediment inputs (sources) and outputs (sinks) on the coasts.
20
Q
What are sediment cells / littoral cells?
A
Lengths of coastline that are pretty much entirely self-contained for the movement of sediment. Each cell is a closed system.
21
Q
What are the four types of sub-aerial weathering?
A
Salt weathering / salt crystallisation
Freeze-thaw
Wetting and drying / pressure release
Chemical weathering
22
Q
How does the process of salt weathering take place?
A
Saline water enters pores/cracks in rocks at high tide.
Tide goes out, rocks dry, water evaporates.
Salt crystals form, expand, exert pressure.
Pieces of rock fall off.
23
Q
How does the process of freeze-thaw take place?
A
Temperatures fluctuate between above and below freezing.
Water enters crevices and joints in rocks.
Freezes and expands below 0.
Melts above 0.
Repetition weakens the rock and it falls off.
24
Q
How does the process of wetting and drying take place?
A
Some rocks containing clay when wet expand.
Pressure caused by this breaks fragments of rock off.
25
What is chemical weathering?
Breakdown of rock due to chemical change.
For example chelation where acids released by decomposition of plants and organic matter attacks rocks.
26
What are the five types of mass movement?
Slumping (shift with rotation)
Rockfall (material breaks up and falls)
Mudflows (material falls downslope)
Slides (in a straight line)
27
What is solifluction?
Flowage of water-saturated soil down a steep slope.
28
What is wave quarrying?
Energy of a wave as it breaks against a cliff is enough to detach bits of rock.
29
What is cavitation?
As waves recede, compressed air expands violently, exerting pressure on rock causing pieces to break off.
30
What is the littoral zone?
The area of land between the cliff’s or dunes on the coast and the offshore
area that is beyond the influence of the waves, covered by the sea at different
points in time.
31
What three factors affect wave energy?
Strength of wind
Duration of wind
Fetch length
32
What is the amphidronic point?
Where there is zero tidal amplitude, complete stillness.
33
What are rip currents?
Strong, localized, and narrow currents of water which move directly away from the shore, cutting through the lines of breaking waves like a river running out to sea.
34
What are riptides?
Occur when the ocean tide pulls water through a small area such as a bay or lagoon.
35
How are wave-cut platforms formed?
Macrotidal conditions required.
Weathering and wave erosion create wave cut notch at high water mark.
WCN forms a cave.
Rock above becomes unstable and unsupported and collapses.
Abrasion makes the WCP flat, slanting towards sea at 3-4 degree angle.
36
What is an example of a WCP?
Walton-on-the-Naze
37
What is meant by macrotidal?
Tidal range more than 4m
38
What is meant by mesotidal?
Tidal range 2-4m.
39
What is meant by microtidal?
Tidal range less than 2m
40
What happens during the process of wave refraction?
Waves undergo change in direction as they approach headlands and bays.
Depth reduces, friction increases, speed reduces, crest distorted into pattern reflecting shape of coastline.
41
What are the main landforms of coastal erosion?
Cliffs
WCP
Caves/arches/stacks/stumps
Headlands and bays
42
How are headlands and bays formed?
Discordant coastline and destructive waves.
Differential rates of erosion erodes softer rock quickly, forming a bay.
Harder rock eroded less forms headlands.
Wave refraction takes places where headlands are significantly sized.
Constructive waves in bays forms beaches.
43
How are stacks formed?
Weathering makes faults and cracks in headland.
Headland attacked by destructive waves.
Geo forms and grows into a cave.
Cave eroded through to form an arch.
Top of arch collapses leaving a stack.
Stacks collapse leaving stumps.
44
What is an example of a sea arch?
Durdle Door, Dorset
45
What is an example of a stack?
Old Harry Stack
46
What are the main landforms of coastal deposition?
Beaches
Spits
Offshore bars and tombolos
Barrier beaches and islands
Sand dunes
47
How are beaches formed?
Constructive waves cause a net gain of sediment on shore through deposition.
48
How are shingle and sand beaches different?
Shingle beaches are steep and narrow, made of larger particles piled at steep angles.
Sand beaches are formed from smaller particles and are wide and flat.
49
What are the main features of a beach?
Berms
Ridges & runnels
Ripples
Cusps
Storm beaches
50
What are berms?
Ridges of sand and pebbles 1-2m high found at high tide marks running along beaches.
51
What are ridges and runnels?
Parallel 'hills and valleys' of sand formed due to the interaction of tides, currents, sediments and the beach topography.
52
What are ripples?
Wave-sculpted ripples formed when low energy waves transfer orbital energy of waves onto sand below.
53
What are cusps?
Crescent-shaped indentations that form on beaches of mixed sand and shingle.
54
What are storm beaches?
A ridge of boulders and shingle found at the back of the beach thrown up by high energy waves during high tide, spring tides, or storm events.
55
How are spits formed?
Drift aligned beach and where coast suddenly changes direction.
LSD deposits sediment across river mouth, leaving bank of sand and shingle sticking out to sea.
Occasional changes to prevailing wind direction cause recurved end.
56
How do compound spits form from simple spits?
Over time several recurved ends result from several periods of growth and abandonment of recurved ends as waves return to original direction.
57
How are barrier beaches formed?
Across a bay or river mouth a spit joins two headlands together, a lagoon forming in behind.
58
How are tombolos formed?
A bar connects the shore to an island, sometimes a stack.
59
What is an example of an barrier beaches?
Slapton Sands, Torcross, Devon
2.3km long, 150m wide. 1km2 lagoon.
60
How do scientists think barrier islands are formed?
In areas with good sediment supplies, small tidal ranges and fairly powerful waves.
Either:
At end of last ice age, sea level rise flooded land behind beaches and transported sand offshore, deposited in shallow water forming islands.
Or:
The islands were originally barrier beaches, eroded in sections causing breaches in the bar.
61
How are sand dunes formed?
Sand deposited by LSD saltated and trapped by driftwood (deposited at spring tide mark) lowering wind speed.
Colonised by marram grass, which stabilises the sand and encourages more sand accretion forming embryo dunes.
62
What is the sequence of types of dune involved in sand dune formation?
Embryo 1-2m
Yellow 5m
Grey 8-10m
Mature 10-15m
63
Why are sand dunes dynamic?
They are in a state of constant change.
64
How did humans impact Camber Sands pre-1900?
1669 Agarian Revolution. Deforestation made way for new farming techniques. Increased: surface runoff, fluvial erosion, river discharge. More sand via River Rother.
1894 Rye Golf Course. Destroyed western sand dunes.
65
How did humans impact Camber Sands in the 20th century?
1944 D-Day Landings. Tanks and people caused dune destruction during training.
1967 Carry on Follow That Camel. Film production damaged the dunes.
1967 Dungeness Power Station. Sand mining took place for the concrete.
1968 Regeneration. Initial construction of dune fencing.
1970s Housing. Houses to North-east limit sand dune expansion.
66
How have humans impacted Camber Sands in the 21st century?
2000 Tourism. 25,000 per day during summer months cause blow-outs.
2014 sea level change. Eustatic and isostatic sea level change could result in drowning of sand dunes.
67
How might Camber Sands be affected by humans in the future?
IPCC 0.8m sea level rise by 2100 could have catastrophic effects on the dunes.
68
What natural factors have affected Camber Sands?
South westerly winds create fetch no greater than 200km limiting des waves.
Macrotidal conditions expose beach for many hours a day, drying it so sand loses cohesiveness.
Halophytic and xerophytic marram grass lowers wind speed and binds sand with roots.
Aeolian processes such as saltation transport sediment up beach during low tide.
69
What is flocculation?
Clay particles clump together due to chemical attraction and then sink due to their high density.
70
What is plant succession?
A plant community that changes over time
71
What makes marram grass a good pioneer plant?
Tough and flexible
Adapted to reduce water loss through transpiration
Roots up to 3m deep
Can tolerate 60 degrees Celsius
72
What are the five stages of plant succession upon salt marshes?
Algal stage (gut weed, blue green algae)
Pioneer stage (cord grass and glasswort)
Establishment stage (grass and sea asters)
Stabilisation (sea thrift, scurvy grass, sea lavender)
Climax vegetation (rush, sedge and red fescue)
73
How are saltmarshes formed?
Green algae and eel grass develop on mudflats trapping sediment/mud which build up.
Halophytic salicornia and spartina colonise the area replacing original colonisers.
Colonise sward zone submerged for only 4/12 hours.
Meadow formed.
Climatic climax of vegetation succession – oak trees develop.
74
How are mudflats formed?
In sheltered low-energy environments.
Silt and mud deposited from fluvial erosion and flocculation.
75
What is eustatic sea level change?
Sea level change caused by a change in the volume of water in the sea.
Eustatic affects everywhere.
76
What are the main ways eustatic change occurs?
Thermal expansion/contraction of water due to temperature changes.
Melting of ice sheets
Temperature drops increase precipitation as snow adding to glaciers decreasing sea level
77
What is isostatic sea level change?
Sea level change caused by vertical movements of the land relative to the sea.
Effects always local
78
What are the main causes of isostatic sea level change?
Uplift or depression of the Earth's crust due to accumulation or melting of ice sheets.
Subsidence of land due to shrinkage after abstraction of groundwater.
Tectonic processes inc. subduction
79
What are the IPCC's predictions for sea level?
0.8m sea level rise by 2100
80
What was the sea level 10,000 years ago?
During the last glacial period (110,000 to 12,000 years ago) water was stored in ice sheets (cryosphere), meaning sea level was 130m lower than it is now.
81
How have sea levels changed over the last 10,000 years?
Temperatures increasing (starting about 12,000 years ago) melted ice sheets, Sea levels rose rapidly, reaching its present level 4,000 years ago.
82
How have global temperatures changed since 1900?
A rapid increase due to global warming has seen a sharp 1.08'C rise (1900-2016) due to anthropogenic activity such as the burning of fossil fuels and deforestation.
83
How do greenhouse gases affect sea level?
GGs absorb outgoing long wave radiation so less leaves the atmosphere. Concentration increases, heating the planet up.
Eustatic sea level rise.
84
At what rate is sea level currently rising?
4mm per year (IPCC)
85
What are the main coastal landforms of emergence?
Raised beaches
Relict cliffs
Marine platforms
Arches/stacks/stumps
86
How are raised beaches formed?
A previously formed beach moves to higher relief due to regional uplift and marine transgression moving the beach high above today's sea level.
87
How are relict cliffs formed?
A previously formed sea cave moves to higher relief due to regional uplift.
88
How are marine platforms / marine terraces formed?
Inconsistent isostatic rebound, where stillstands occur mean WCPs can form between rebounds, causing the platform become the terrace.
89
What is an example of a raised beach?
Isle of Arran, Scotland
Lower beach 8m elevation.
Higher beach 30m elevation.
90
What is an example of a relict cliff?
King's Cave, Isle of Arran, Scotland.
10m high, 15m wide.
91
What are the main coastal landforms of submergence?
Rias
Fjords
Dalmation coastlines
92
How are rias formed?
River valleys are created by the vertical erosion of rivers by abrasion and hydraulic action
The valley is widened to form a floodplain by lateral erosion on the outside of meanders that force back the valley sides (bluff lines)
Rias are created by eustatic sea level rise
This has risen and spilled over the former river valley to submerge it and create a Ria
93
What are the characteristics of rias?
Gentle long and cross profile
Wide and deep at mouth
Narrow and shallow inland
Dendritic pattern
94
What is an example of a ria?
Kingsbridge, South Devon
Runs 5 miles north to Salcombe
95
How are fjords formed?
Glacier formed. Plucking and subglacial erosion erodes rock vertically, forming U shaped valley.
Warmer conditions melt the glacier leaving valley behind.
Thermal expansion of water/eustatic sea level rise submerges valley leaving fjord.
96
What is an example of a fjord?
Sognefjorden, Norway
300km long west to east
97
How are dalmation coastlines formed?
On a concordant coastline weathering and erosion remove the softer material faster than the hard material
Differential erosion creates a parallel system of highlands and valleys
Eustatic sea level rise causes marine transgression flooding the valleys and left the highlands as islands
98
What is the example of a dalmation coast?
The Dalmation Coast, Zadar Croatia
99
What is a damlation coastline?
A series of elongated islands that sit parallel to the coastline
100
What is a fjord?
A drowned U-shaped glacial origin valley,
101
What is a ria?
A drowned river valley.
102
How might coastal communities be affected by climate change?
Some areas of the coast may have significantly reduced house and land prices (as the area becomes known to be at significant risk) leading to economic loss for homeowners and local coastal economies . In the UK, many insurers don’t provide home insurance to people living along coastlines that are at extreme risk of erosion or storm surges.
103
What are the four options for coastal management?
Hold the line
Advance the line
Do nothing
Managed retreat
104
How does a sea wall protect a coastline?
It reflects waves back out to sea preventing erosion and acts as a barrier against flooding.
A curved sea wall have steps in front of them to break waves with friction.
105
What are the advantages of sea walls?
Protection against erosion and flooding.
Can be used for renewable energy.
Don't require much space (vertical).
Long-lasting and durable.
106
What are the disadvantages of sea walls?
Any slight gap exploited by hydraulic action.
Expensive to build (£2m-£5m per km) and repair.
Reflecting waves creates strong backwash and cause beach scour.
Extra defences may be needed to prevent this e.g. rock armour.
107
How do revetments protect a coastline?
Slanted structure breaks waves, absorbing energy, preventing erosion.
108
What are the advantages of revetments?
Cheaper to maintain than others.
Erodes less beach material than a sea wall.
Absorb energy through the slats.
109
What are the disadvantages of revetments?
Short life span, especially wooden.
Expensive to build (£2m-£5m per km).
Not suitable for an extremely high energy coastline as they may cause damage to permeable surfaces.
Not effective in stormy conditions.
Aesthetically displeasing.
110
How do groynes protect a coastline?
Built perpendicular to the beach to trap material transported by LSD, creating wider beaches, slowing the waves, reducing their energy, protecting the coast from flooding and erosion.
111
What are the advantages of groynes?
Highly effective in preventing LSD, building up material to prevent beach starvation.
Keeps large amounts of material on the beach, attracting tourists.
112
What are the disadvantages of groynes?
Expensive to build and maintain £1,000-£4,000 per metre.
Short lifespan.
Starve down-drift beaches of sand.
Thinner beaches don't protect coast as well, leading to greater erosion and flooding.
113
How do tidal barrages protect the coastline?
Dam-like structures protect high value land from flooding .
114
What are the advantages of tidal barrages?
Relatively inexpensive considering the value of land they protect and their lifespan.
The Thames Barrier has operated since 1984 and will last up to 2035, and protects billions of pounds of London's economy.
115
What are the disadvantages of tidal barrages?
Change movement of water into and out of estuaries, disrupting lifecycles of certain marine life.
High initial cost (Thames Barrier was £534m).
Prevent access to rivers and cut off shipping.
116
How do offshore breakwaters protect coastlines?
Provide shoreline protection by intercepting incoming waves. They create stable pocket beaches between them as they act like headlands.
Sea Palling on the North Norfolk coast were made of 312,000 tonnes of concrete in 1995 and are 2.8m high.
117
What are the advantages of offshore breakwaters?
Great at absorbing energy from oncoming waves and protect other sea defences.
Low energy conditions behind cause deposition and beaches to build up.
118
What are the disadvantages of offshore breakwaters?
High economic cost. Sea Palling cost £5.9m.
Encouraging deposition means less sediment moves down drift. This causes beach starvation further along the coast.
119
How do gabions protect coastlines?
Rock-filled cages, they absorb and dissipate wave energy.
120
What are the advantages of gabions?
Cheap and provide short-term (5-10 years) protection from backshore erosion.
Blend into landscape.
Stackable to act as flood defences.
Ease of handling and transportation.
Speed of construction.
Flexibility.
121
What are the disadvantages of gabions?
Low habitat value
More expensive than vegetated slopes or rip rap.
Don't last long.
122
How does riprap / rock armour protect coastlines?
Boulders absorb impact. Gaps reduce energy, reducing erosion. Normally paired with a sea wall.
123
What are the advantages of riprap?
Easy to maintain.
Eco-friendly.
Long-lasting.
124
What are the disadvantages of riprap?
Can cost up to £50 per square yard.
Aesthetically displeasing.
Can be dangerous to people and animals.
Can shift in storms.
125
How do earth banks protect coastlines?
Mounds on earth act as a barrier to prevent flooding.
126
What are the six main methods of soft engineering?
Beach nourishment
Beach stabilisation
Dune regeneration
Land use management
Creating marshland
Managed retreat
127
What is beach nourishment?
Sand and shingle added to beaches from elsewhere e.g. dredged from offshore. Creates wide beaches which make coastlines lower energy.
128
What is beach stabilisation?
Can be done by reducing the slope angle and planting vegetation, or by sticking stakes and old tree trunks in the beach to stabilise sand. Reduces erosion of cliffs by creating wider beaches.
129
What is dune regeneration?
Sand dunes are created or restored by either nourishment or stabilisation of the sand. Dunes provide a barrier between land and sea, absorbing wave energy and preventing flooding and erosion.
130
What is land use management?
Vegetation needed to stabilise the dune can be easily trampled and destroyed, so wooden walkways and fencing off areas prevent walkers, cyclists or 4x4s accessing the dunes.
131
How can marshland be created to protect coastlines?
Planting appropriate vegetation (e.g. glassworts) stabilises the sediment. Stems and leaves reduce wave speed, reducing erosive power and how far the waves reach inland, leading to less flooding.
132
How does managed retreat protect coastlines?
Breaching an existing defence and allowing the sea to flood the land behind. Over time vegetation will colonise the land and it'll become marshland.
133
What is an example of sand dune regeneration in the UK?
Sefton Coast management scheme.
134
What are the advantages of sand dune regeneration?
Barrier created to reduce flooding and erosion.
Increases the size of the psammosere, creating a habitat for wildlife.
Re-uses a waste product to reduce the amount to landfill.
Tourism.
135
What are the disadvantages of sand dune regeneration?
Lack of access.
Locals argue hard engineering makes them feel more secure.
Could lead to beach starvation further along the beach.
136
What is an example of a managed retreat scheme in the UK?
Abbotts Hall Farrm, Salcott Creek, Blackwater Estuary Essex
120 acres flooded
137
What are the advantages of managed retreat?
Creeks provide a storage area of excess water to reduce pressure elsewhere during storm surges.
Low economic maintenance costs.
Reduces coastal squeeze by creating a halosere habitat.
138
What is an example of beach nourishment in the UK?
The Sospan Dau boat deposits 20,000m3 of sediment at Pevensey Bay, East Sussex.
139
What are the advantages of beach nourishment?
Lower economic cost than a sea wall.
Aesthetically pleasing.
Natural habitat improves biodiversity.
140
What are the disadvantages of beach nourishment?
Requires annual maintenance to maintain beach size.
Some people feel more secure with a sea wall (perceptions).
141
What is a cost-benefit analysis?
The expected cost of the construction, demolition, maintenance etc. of a coastal management plan is compared to the expected benefits of a scheme which may include the value of land, homes and businesses that will be protected.
142
What threats are posed to the Mediterranean?
Sea pollution from industry and untreated sewage. 101 sites.
Damage to landscape from unsightly hotels and holiday resorts.
Desertification due to increase in water extraction from rivers and underground sources.
Air pollution from industry and car emissions.
Oil leaks from ships using the Med.
Increase in aquaculture.
143
What is the Blue Plan?
A report outlining the current state of the Mediterranean area and suggest what can be done to stop its continued destruction. It was created by the UNEP in 2006 to clean up the Med by 2020.
144
What are the Blue Plan recommendations to reduce pressures on the Mediterranean Sea?
10% of coastal area protected by turning them into nature reserves.
Green areas between building complexes.
Inland tourism to reduce pressure on coast.
Sewage/waste water treatment.
Energy saving methods and renewable energy.
Promote water efficiency.
145
Where is the Sundarbans located?
South-west Bangladesh and east India.
World's largest delta 10,000km2.
Alluvial deposits of the Ganges, Brahmaputra and Meghna rivers.
146
What coastal processes shape the Sundarbans?
Tidal action within interconnected channels across silt and mud deposits.
Smaller interconnected channels (Khals) drain the land with ebb tides.
Non-cohesive sand washed away to form Chars (banks).
This sediment blown at coast to create dunes colonised by halophytic plants which succeeds to become mangrove forest.
147
What goods provide opportunities for humans at the Sundarbans?
Timber provides fuel and construction material.
Fishing materials.
Food (fish, shrimp, fruit, alcohol).
Textiles (furs, skins, synthetic fibres, dyes).
Medicines.
Feed for cattle.
Paper.
148
What services provide opportunities for humans at the Sundarbans?
Protection from flooding, erosion, tidal surges, powerful waves from cyclones.
Breeding grounds, nursery grounds, fishing grounds, coastal livelihoods, local and global climate change controls.
Tourism.
Research.
Carbon capture.
Employment.
149
What are risks/challenges are posed to humans living in the Sundarbans?
Eustatic sea level rise.
Late Stage 2 on Demographic Transition Model, natural increase adds pressure on available resources, making sustainable management more difficult.
Tropical cyclones cause floods. 1991 8m high storm surge killed 150,000 people.
Pollution from industry contaminates water and reduces fish stocks.
Destruction of mangroves makes people more vulnerable to coastal erosion and flooding.
Increasing soil salinity from rising sea levels reduces soil fertility.
150
What makes mangrove forests such a valuable commodity to the Sundarbans?
Highly resilient. Shelter against storm winds, floods, tsunamis, erosion.
30 trees per hectare reduces destructive force of a tsunami by up to 90%.
1 hectare of mangrove forests have an annual economic value of over $12,000.
151
What are the main methods of mitigation in the Sundarbans against challenges?
Coastal embankment project
Mangrove forests
Khas land
152
How does eustatic sea level rise pose a threat to the Sundarbans?
The enhanced greenhouse effect has caused eustatic sea level rise.
IPCC 0.8m 2100.
Cat 5 cyclones.
Increased erosion rates 14-15m per year retreat in some areas (Bangladesh Space Research and Remote Sensing Organisation).
153
How has the coastal embankment project mitigated against the challenges in the Sundarbans?
Joint funding from World Bank and Bangladeshi government.
3km length of earth and concrete embankments around char located town Galachipa in the Barisal Division to protect 300,000 inhabitants.
Stabilise physical environment.
154
How is the Khas land in the Sundarbans used to mitigate against the challenges in the Sundarbans?
Government owned land protect for locals to use. Used in times of adversity by farmers who have lost their land to flooding.
155
What are the three main methods of adaption to challenges in the Sundarbans?
Floating farms
Salt tolerant rice
Community Based Ecological Mangrove Restoration
156
What is a drawback of the coastal embankment project in the Sundarbans?
Greater deposition within drainage channels has lowered their carrying capacity, making the embankments less effective.
Less flooding in the non-tidal zone can also reduce the amount of nutrients that arrive onto the farmland, reducing farm productivity.
157
How have the floating farms worked to adapt to challenges in the Sundarbans?
3km2. Banaripara.
Hyacinth plants interwoven to create a bed that floats on rising waters. Balls of organic material with seeds inserted. As the hyacinth plants decay they provide nutrients to the seed to develop it into a productive crop.
158
What are the benefits of the floating farms in the Sundarbans?
Crops not drowned by rising waters; flooded for 9/12 months of the year.
Appropriate technology - can be developed and maintained by local people.
159
What are the disadvantages of the floating farms in the Sundarbans?
High salinity conditions can kill non halophytic crops.
160
How has the salt tolerant rice worked to adapt to challenges in the Sundarbans?
Halophytic breeds of rice developed by the International Rice Research Institute (IRRI).
This allows the rice to survive in double the normal levels of salinity, so harvest can still be gained despite minor levels of flooding.
161
What are the disadvantages of the salt tolerant rice in the Sundarbans?
IRRI made $2.4 million in profits in 2018 developing new breeds of rice for customers to buy. To maintain these profit margins they will have to set unaffordable prices.
NGOs will then have to help farmers afford the crops.
Rice can't cope with extreme salinity and flooding that can be experienced in South. Salinity to increase over threefold in future, too salty.
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How does the Community Based Ecological Mangrove Restoration project help adaption to challenges in the Sundarbans?
In the West Bengal part of the Sundarbans it works with indigenous people to restore natural hydrological processes.
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What are the advantages of the Community Based Ecological Mangrove Restoration project?
It is an effective coastal defence and does not interfere with natural processes.
It prevents 'tragedy of the commons'.
Helps reverse the 84% destruction of mangroves due to shrimp aquaculture.
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What is an ICZM?
Integrated coastal zone management (ICZM) is a holistic process to promote sustainable management of coastal zones. It covers the full cycle of information collection, planning (in its broadest sense), decision making, management and monitoring of implementation.
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What is an SMP?
Shoreline Management Plans (SMP) are used in the UK to set out a strategy for the coastal management of a section of the coastline.
Each SMP covers an area of coastline known as a sub-cell within a littoral sediment cell, of which there are eleven on the England and Wales coastline.
