Coasts Flashcards
(86 cards)
1
Q
Name a case study for a coastline that has a concordant side and a discordant side.
A
The Purbeck Coast.
2
Q
Give an example of a Cove.
A
Lulworth Cove on the Purbeck coast.
3
Q
Give an example of a Bay.
A
Worbarrow bay, Studland Bay or Swanage Bay on the Purbeck coast.
4
Q
What are the four methods of material transportation by the sea?
A
Suspension, solution, saltation and traction.
5
Q
Give an example of a blowhole.
A
Stair Hole in south Purbeck.
6
Q
What is a tombolo?
A
A spit that extends from the mainland to an island.
7
Q
When does deposition occur?
A
When there is insufficient energy to move sediment further.
8
Q
State three significant factors in a low energy environment.
A
Wave and wind direction, the supply of sediment and the depth of the water.
9
Q
How do swash-aligned beaches form?
A
When waves break parallel to the coast.
10
Q
How do drift-aligned beaches form?
A
When longshore drift moves material down the coast producing a range of partly detached features.
11
Q
State three landforms of swash-aligned beaches.
A
Bay beaches, bay bars and barrier beaches.
12
Q
State three landforms of drift-aligned beaches.
A
Spits, bars and tombolos.
13
Q
What type of system is the coastal system?
A
Open system
14
Q
Where does most of the sediment in coasts come from?
A
Rivers
15
Q
Describe a constructive wave.
A
Strong swash and weak backwash, flatter and smaller than destructive waves, causes material to ‘spill’ forward.
16
Q
Describe a destructive wave.
A
Weak swash and strong backwash, taller and wider than constructive waves, causes material to be dragged back.
17
Q
What is an input in a coastal system?
A
Sediment or energy brought into the system.
18
Q
What is an output in a coastal system?
A
Sediment of energy washed out to sea or deposited further along the coast.
19
Q
State four examples of flows/transfers.
A
Erosion, weathering, transportation and deposition.
20
Q
Give three examples of stores/components.
A
Landforms such as beaches, dunes and spits.
21
Q
What is negative feedback?
A
When a change in the system causes other changes that have the opposite effect.
22
Q
What is positive feedback?
A
When a change in the system causes other changes that have a similar effect.
23
Q
State six sources of energy in coastal systems.
A
Wind, waves, tides, currents, Sun and tectonics (tsunamis).
24
Q
Describe a high energy coastline.
A
Receives high inputs of energy in the form of large, powerful waves caused by strong winds and long fetches. High energy coastlines tend to have sandy coves and rocky landforms such as cliffs, caves, stacks and arches. The rate of erosion is often higher than the rate of deposition.
25
Describe a low-energy coastline.
Receives low inputs of energy in the form of small, gentle waves caused by gentle winds (in sheltered areas) and short fetches. Low-energy coastlines often have saltmarshes and tidal mudflats. The rate of deposition is often higher than the rate of erosion.
26
Give a reason for a coast being of low-energy.
There is a reef or island offshore which protects the coasts from the full power of the waves.
27
How are waves formed?
By wind blowing over the surface of the sea. The friction between the wind and the water gives the water a circular motion.
28
What is wind created by?
Air moving from areas of high pressure to low pressure.
29
What are tides?
The periodic rise and fall of the ocean surface caused by the gravitational pull of the moon and sun.
30
What are currents?
General flow of water in one direction.
31
Other than wind, what can currents be caused by?
variations in water temperature and salinity.
32
When do beaches form?
When constructive waves deposit sediment on the shore.
33
What is the difference between sand and shingle beaches?
Shingle beaches are steep and narrow and made up of larger particles whereas sand beaches are wide and flat and formed from smaller particles.
34
Where are berms, ridges, runnels and grooves found on a beach?
Berms and ridges are found at high tide marks and runnels and grooves are found lower down the beach.
35
What is a cusp?
A crescent-shaped indentation that forms on beaches of mixed sand and shingle.
36
Where do spits form?
Where the coast suddenly changes direction e.g. across a river mouth.
37
How do spits form?
Longshore drift continues to deposit sediment across an area where the coast suddenly changes direction.
38
What do occasional changes in wind direction cause a spit to have?
A recurved end
39
What could be formed if longshore drift occurs where there is a recurved end on a spit?
A compound spit which is a spit with multiple recurved ends.
40
What is usually found behind long spits and compound spits?
A marshy area where mudflats and saltmarshes form.
41
What is a bar?
Where a spit extends from one part of the mainland to another part of the mainland.
42
What is the area behind a bar called?
A lagoon.
43
How is an offshore bar formed?
By material moving towards the coast as sea level rises forming a bar which remains partly submerged by the sea.
44
What is a barrier beach/island?
A long, narrow island of sand or gravel that runs parallel to the shore and is detached from it.
45
State four factors that could lead to the formation of barrier beaches/islands.
Good supply of sediment, gentle slope offshore, fairly powerful waves and a small tidal range.
46
How do sand dunes form?
Sand is moved along the coast by longshore drift the blown up the coast by wind. It is then caught by driftwood or berms and colonised by plants and grasses such as marram grass which stabilises the sand encouraging more sand to accumulate here. Over time, the oldest dunes move inland and newer embryo dunes are formed.
47
State nine hard engineering strategies.
Sea wall, Revetment, gabions, riprap, groynes, breakwaters, earth banks, tidal barriers and tidal barrages.
48
What is a revetment?
A slanted sea wall placed at the foot of cliffs to absorb wave energy to prevent erosion of the cliff.
49
What are gabions?
Rock filled cages placed at the foot of cliffs to absorb wave energy.
50
What is riprap?
Boulders pilled along the coast to absorb wave energy to reduce erosion.
51
What are breakwaters?
A concrete block or boulder placed offshore to force waves to break offshore so they lose their erosive power before they reach the shore.
52
What is an earth bank?
A mound of earth which acts as a barrier to prevent flooding.
53
What is a tidal barrier?
A barrier built across river estuaries which contains retractable floodgates to protect against flooding from storm surges.
54
What is a tidal barrage?
A hydroelectric dam which can control the release of water and prevent flooding.
55
State six soft engineering strategies.
Beach nourishment, beach stabilisation, dune regeneration, land use management, creating marshland and managed retreat.
56
What is beach stabilisation?
Reducing the slope angle of the beach and planting vegetation or using stakes and old tree trunks to stabilise the sand. This makes the beach wider which reduces erosion of cliffs.
57
What is land-use management on a coast?
Building walkways and fencing-off areas to prevent trampling of new vegetation.
58
What is a shoreline management plan?
Where the coastline is split into sediment cells each for which a plan is devised on how to best protect important sites in that cell without compromising other areas of the cell.
59
What is Integrated coastal zone management (ICZM)?
ICZM considers all elements of the coastal system and aims to protect it in a natural way whilst allowing people to continue to use and develop it. It is a dynamic strategy which means if there is a change in the demands of the area, decisions can be re-evaluated.
60
What are the three main rivers in the Sundarbans in Bangladesh?
Ganges, Brahmaputra and Meghna.
61
Where are the Sundarbans and which body of water is it next to?
South-west Bangladesh and east India next to the Bay of Bengal to the South.
62
What type of tree grows in the Sundarbans?
Mangrove.
63
How has the Mangrove adapted to grow in the Sundarbans?
They have adapted to living in salt water and grow on mud flats.
64
How is the Sundarbans protected?
It is a national park.
65
What causes the Sundarbans to remain in dynamic equilibrium?
Material is being deposited by the rivers but also eroded by the sea so the size of the sediment store remains roughly the same.
66
How many people live in the Sundarbans?
4 million people.
67
What do the residents of the Sundarbans gain from the area?
A range of natural products such as fish, crabs, honey, palm leaves and timber which can be sold for economic benefits to the region.
68
Why is the land in the Sundarbans ideal for growing crops?
The land is flat and fertile in the river deltas.
69
Why do mangroves make it easier to live in the Sundarbans?
They provide a natural defence against flooding because they act as a barrier and coastal erosion because the roots bind the soil together which makes it easier to live and grow crops.
70
State three opportunities for development in the Sundarbans.
Tourism, cargo ships being allowed to use the waterways and a power plant has been proposed just north of the national park.
71
State eight risks for occupation and development in the Sundarbans.
Lack of fresh water due to it being diverted for irrigation upstream, parts of the forest are being removed due to the growing population which increases flood risk, flooding can lead to salinisation of soil making it hard to grow crops, there are dangerous animals such as tigers and sharks and crocodiles, there is a lack of employment and income opportunities, the low-lying land is at risk from rising sea levels, the area is poor and most people don’t have access to electricity so don’t receive flood warnings, access is difficult so residents find it hard to receive goods and healthcare and education.
72
State five methods of resilience in the Sundarbans.
Improving clean water and sanitation, improving roads and bridges, providing mains electricity, providing farm subsidies to increase food security and decrease poverty, NGOs offering training in sustainable methods of fishing and farming.
73
State three methods of mitigation in the Sundarbans.
3500km of embankments were built to prevent flooding however these are being eroded, protect existing mangrove forests and replant areas that have been removed, funding cyclone shelters and early warning systems however people may not have the transport available to evacuate.
74
State four methods of adaptation in the Sundarbans.
Growing salt-resistant rice, increase tourism to the area providing jobs and income by building lodges and running boat trips, building houses on stilts, sustainable adaptations such as non-intensive farming practices and promoting ecotourism.
75
What is a fjord?
A drowned glacial valley, very straight and narrow with very steep sides. They have a shallow mouth caused by a raised bit of ground called the threshold formed by deposition of material by the glacier. They’re very deep further inland, e.g. Sognefjorden in Norway is over 1000m deep in places.
76
What is a dalmatian coastline?
When a valley which is parallel to a coast floods due to an increase in sea level, it creates islands parallel to the coastline. This is called a dalmatian coastline.
77
Where do salt marshes form?
Behind spits and low wave-energy environments.
78
Give an example of a salt marsh.
Keyhaven Marsh.
79
How big is Keyhaven Marsh?
Covers approximately 2 square kilometres.
80
State two sources of sediment for a salt marsh.
Clay and silt deposited by wave and tidal action, sediment transported by rivers.
81
Give an example of a negative feedback mechanism in a coastal environment and explain how it works.
A beach in dynamic equilibrium. Sediment is eroded from the beach during a storm, sediment is deposited offshore forming an offshore bar, waves are now forced to break before reaching the beach which dissipates their energy and reduces further erosion, when the storm calms to normal wave conditions rework sediments from the offshore bar back to the beach.
82
Give an example of a positive feedback mechanism in a coastal environment.
Groynes trap sediment being transported by longshore drift, depriving down-drift beaches of replenishment, increases erosion rates.
83
State three features of a low-energy coastline.
Sheltered from storms by barrier islands, reefs or a headland.
Broad, gently sloping shelves dissipate energy of waves.
Depositional landforms are common.
84
Give two examples of soft rock.
Limestone and chalk.
85
Give an example of resistant rock.
Granite.
86
How many sediment cells are there in the UK?
11
