Flashcards
Geography GCSE Coasts
Cards in this deck (86)
- 1How are Wave-Cut Platforms formed?1. Waves cause most erosion at the foot of the cliff
2. This forms a wave-cut notch, which is enlarged as erosion continues
3. The rock above the wave-cut notch becomes unstable and eventually collapses
4. The collapsed material is carried away and a new wave-cut notch starts to form
5.Repeated collapsing results in the cliff retreating
6. A wave-cut platform is the platform which is left behind as the cliff retreats - 2Where do Headlands and Bays form along?Headlands and Bays form along Disconcordant Coastlines
- 3How are Headlands and Bays formed?(Soft rock or rocks with lots of joints have a low resistance to erosion.
Hard rocks with a solid structure have a high resistance to erosion)
1. Headlands and Bays are formed where there are alternating bands of less resistant and resistant rock along a coast.
2. The less resistant rock (e.g. clay) is eroded more quickly and this forms a bay. Bays have a gentle slope.
3. The resistant rock (e.g. chalk) is eroded more slowly and is left jutting out, forming a headland. Headlands have steep sides - 4How are caves, arches and stacks formed?1. Headlands are usually made of resistant rock that have weaknesses like cracks.
2. The wave crash into the headlands and enlarges the cracks- mainly by hydraulic power and abrasion
3.Repeated erosion and enlargement of the cracks causes a cave to form
4. Continued erosion deepens the cave until it breaks through the headland-forming an arch (Durdle Door in Dorset)
5. Erosion continues to wear away the rock supporting the arch, until it eventually collapses
6. This forms a stack-an isolated rock that's separate from the headland, e.g. Old Harry - 5Describe the process of long-shore drift:1.Waves follow the direction of prevailing winds
2. They usually hit the coast at an opaque angle (any angle which is not at right angles)
3. The swash carries material up the beach , in the same direction as the waves
4. The backwash carries material down the beach at right angles, back towards the sea
(Look at CGP book for diagram) - 6What do deposited sediment form?Deposited sediment form Spits and Bars
- 7How are spits formed?1. Spits form at sharp bends in the coastline e.g.river mouth
2. Longshore drift transports materials such as sand,shingle past the bend and deposits into the sea
3.Strong winds and waves can curve the end of the spit (forming a recurved end)
4. The shelter area behind the spit is protected from waves- lots of material accumulates in this area, which mean plants can grow there.
5. Over time, the sheltered area can become a mud-flat or a salt marsh - 8How is a bar formed?A bar is formed when a spit joins two headlands together
The bar cuts off the bay between the headlands from the sea
This means a lagoon can form behind the bar - 9What are direct effects?Direct effects are the immediate effects of something
- 10What are indirect effects?Indirect effects happen as a result of the direct effects
- 11What are the Human Activities that have effects on the coast?1.Agriculture
2. Development
3.Industry
4. Coastal Management - 12Explain Agriculture:1. Agricultural land has a low economic value and is often left unprotected. This has a direct effect on coastal landscapes because the sea can erode the cliffs and shape the land.
2. Changing the way farming land is used can affect the stability of cliff
*Vegetation helps to bind the soil together to stabilise the clifftop.
*Clearing vegetation from grazing land to make more room for crops can expose the soil and underlying rock, leaving it vulnerable to weathering by wind and rain .
3. Land e.g. marshland , is sometimes reclaimed and drained for agricultural use. Draining marshland directly affects the coast because it reduces the natural flood barrier that marshland provide - 13Explain development:1. Coastal areas are a popular place to live and work, so they often have lots of development e.g. hotels and infrastructure
2. Coasts with lots of settlement may have more coastal defenses because people want to protect their homes and businesses. This is a positive direct effect on the coastline because the land is better protected from erosion.
3. However, an indirect effect is the change in transportation and deposition of material along the coast.
Building on coastal lowlands can restrict the supply to beaches, making them narrower. Narrow beaches don't protect the coast as well, which means the land is more vulnerable to erosion - 14Explain Industry:1) Coastal quarries expose large areas of rock, making them more vulnerable to weathering and erosion
2) Gravel has been extracted from some beaches for use of construction industry, e.g. making concrete
This has removed material from the coast and increased the risk of erosion because there's less material to protect cliffs
3. Industrial growth at ports has led to increased pressure to build on salt marshes. These areas provide flat land and sheltered water, which are ideal for ports and industry, but are also natural flood barriers.
Building on salt marshes leaves the land more vulnerable to erosion - 15Explain Coastal Management:1. Coastal management is about protecting coastal landscapes from the impacts of erosion
2. Some management strategies alter the sediment movement, which reduces the amount of protective beach material further along the coast-increasing erosion
3.Coastal defenses can also reduce erosion. This has a direct effect on the coast because it prevents the landscape from changing i.e retreating - 16How is climate change increasing coastal flooding?Climate change is increasing coastal flooding because of:
1. Rising sea levels
2. Storm frequency - 17How do rising sea levels increase risk of coastal flooding?1. Rising sea levels pose a threat to low-lying and coastal areas
2. Rising sea levels leads to higher tides that would flood coastal areas more frequently
3. Higher tides could remove large amounts of materials from beaches. This could lead to increased erosion of cliffs because there's less material to protect them from the sea
4. Rising sea levels could expose more of the coast line to erosion- beaches become narrower as the sea will be able to move further inland - 18How does storm frequency increase risk of coastal flooding?1. Climate change is making storms to become more frequent
2. Storms give the sea more erosional powers as they increase frequency of destructive waves.
Areas of hard rock will be more vulnerable to erosion and areas of soft rock will erode more quickly
3. The sea will also have more energy to transport material. High energy waves can move more material for greater distances, which could lead to some areas being starved of material. This leaves these areas vulnerable to erosion and to flooding - 19What are the threats to people due to coastal flooding?1. Low-lying coastal areas could be permanently flooded or flood so often that it would be impossible to inhabit
2. Coastal industries may have to shut down due to damage to equipment and buildings e.g. fishing boats can be destroyed
3. There's a risk of damage to infrastructure like roads and rail networks
4. There's a booming tourist industry in coastal areas. Flooding and erosion may put people off from visiting. Fewer tourists means businesses that rely on tourism may close, leading to a loss of livelihoods - 20What are the threats to the environment due to coastal flooding?1. Ecosystems are affected because seawater has a high salt content. Increased salt levels due to coastal flooding can damage or kill organisms in an ecosystem
2. Increased salt levels due to coastal flooding can reduce the soil fertility in agricultural land
3. The force of flood water can also uproot trees and plants destroying animal habitats also
4. Some conservation areas are threatened by coastal erosion - 21What is the aim of coastal management?The aim of coastal management is protect people and the environment from the impacts of erosion
and flooding - 22What is hard engineering?Man-made structures built to control the flow of the sea and reduce flooding and erosion
- 23What is soft engineering?Schemes set up using knowledge of the sea and its processes to reduce the effects of flooding and erosion
- 24What are the two examples of hard engineering?1. Sea Wall
2. Groynes - 25What are three examples of soft engineering?1. Beach replenishment
2. Slope Stabilisation
3. Strategic realignment - 26Describe Sea Walls: 1. What it is 2. Benefits 2. CostsWhat is it?
A sea wall is a hard wall like concrete which reflects the waves back to sea
Benefits:
It prevents erosion of the coast
It acts as a barrier to prevent flooding
Coasts:
It creates a strong backwash which erode under the wall
Seawalls are expensive to build and maintain - 27Describe Groynes: 1.What it is? 2. Benefits 3. CoastsWhat is it?
A groyne is a wooden or stone fence that is built at right angles to the coast
They absorb wave energy and trap sediment transported by longshore drift
Benefits:
They create wider beaches which slow the waves. This gives greater protection from flooding and erosion.
They are a fairly cheap defense
Costs::
They starve beaches further down the coast of sand, making them narrower.
Narrower beaches don't protect the cost as well, leading to greater erosion and floods further down the coast. - 28Describe Beach Replenishment: 1.What it is? 2. Benefits 3. CoastsWhat is it?
Beach replenishment is when sand and shingle from elsewhere or lower down the beach are added to the upper part of beaches
Benefits:
It creates wider beaches which slow the waves. This gives greater protection from flooding and erosion
Costs:
Taking material from the seabed can kill organisms such as sponges and corals
It's very expensive and has to be repeated - 29Describe Slope Stabilisation: 1.What it is? 2. Benefits 3. CoastsWhat is it?
Slope stabilisation is when slopes are reinforced by inserting concrete nails into the ground and covering the slope with metal netting
Benefits:
It prevents mass movement by increasing the strength of the slope.
Costs:
Slope stabilisation is very expensive and sometimes it very difficult to install - 30Describe Strategic Realignment: 1.What it is? 2. Benefits 3. CoastsWhat is it?
Strategic Realignment is when an existing defence is removed allowing the land behind it to flood
Benefits:
Overtime the land will become marshland-creating new habitats
Flooding and erosion are reduced behind the marshland
Costs:
People may disagree over what land is allowed to flood e.g. flooding farmland would affect the livelihoods of farmers - 31What are the costs and benefits of doing nothing?Benefit:
It is cheap as no new coastal defences are built
Nature is taking its course
Coasts:
It doesn't coast anything to let the coast retreat naturally but infrastructure for tourism
People might also be forced to move away from the area because of the risk of erosion and flooding - 32Why do management strategies need to be sustainable?Management strategies need to be sustainable to protect the coast and avoid conflict
Sustainable management strategies means making sure that erosion and flooding are controlled without causing more problems elsewhere (e.g. erosion further down the coast) or affecting the people who live and work at the coast.
Strategies also need to be cheap to avoid conflicts about the spending of public money - 33What is ICZM? (Intergrated Coastal Zone Management)It is an approach that aims to protect the coast while taking everyone's interests into account- this makes it easier to find solutions that people can all agree on.
It is also a long-term approach so it can be adapted to any future needs and changes along the coastline. This makes it sustainable approach to managing the coast - 34Describe the Upper-course of a river: Gradient Valley and channel shapeThe upper course of a river is found near a source therefore it has a steep gradient
The Valleys are....
V-shaped and have steep sides
Channel shape is ...
Narrow and Shallow - 35Describe the Middle-course of a river: Gradient Valley and channel shapeIt has a medium gradient
The valley shape is...
gently sloping valley sides
The channel shape is wider and deeper - 36Describe the Lower-Course of a river: Gradient Valley and channel shapeGradient= Gentle
The valley shape is...
very wide and almost flat valley
The channel is...
very wide and deep - 37What is vertical erosion?Vertical erosion deepens the river valley and channel.
It is more dominant in the upper course of a river
High turbulence causes the rough, angular particles to be scraped along the river bed, causing intense downwards erosion - 38What is lateral erosion?Lateral erosion widens the river valley and channel during the formation of meanders.
It is more dominant in the middle and lower course of a river - 39What is freeze thaw weathering and what happens during freeze thaw weathering?Freeze thaw weathering is a type of mechanical weathering
1. Freeze-thaw weathering happens when the temperature alternates above and below zero degree celsius
2. Water gets into rocks that have cracks e.g. granite. When the water freezes the rock expands putting pressure on the rock.
When the water thaws the rock contracts, which releases the pressure on the rock.
3.Repeated freezing and thawing widens the cracks and causes the rock to break up - 40What are the four processes of erosion which occur in river channels/ coasts?1. Hydraulic Power
2. Abrasion
3. Attrition
4. Solution - 41What happens during hydraulic power?Hydraulic power is when waves crash against the rock and compress the air in the cracks. This puts pressure on the rock. Repeated compression widens the cracks and makes bits of rock to break off
- 42What happens during abrasion?During abrasion the eroded particles in the water rub and scrape against the rocks , removing small pieces
- 43What happens during attrition?During attrition, the eroded particles in the water smash into each other and break smaller fragments
- 44What happens during solution?During solution some rocks are dissolved by rain water e.g. chalk and limewater
- 45What are the four ways in which material is transported?1. Traction
2. Saltation
3. SUspension
4. Solution - 46What is traction?Traction is when large particles such boulders are pushed along the riverbed by the force of the water
- 47What is suspension?Suspension is when small particles such as silt and clay are carried along by the water
- 48What is saltation?Saltation is when pebble-sized particles were bounced along the riverbed by the force of water
- 49What is solution?Solution is when soluble materials dissolve in the water and is carried along
- 50What is deposition?Deposition is when the river drops the eroded material it is transporting.
It happens when a river slows down - 51Why do rivers slow down and deposit materials?1. The volume of water in the river falls
2. The amount of eroded material in the water increases
3. The water is shallower e.g. on the inside of a bend
4. The river reaches it's mouth - 52What river landforms are found in the upper course of a river?1. Water Falls
2. Gorges - 53How are waterfalls formed?1.Waterfalls are formed when a river flows over area of hard rock followed by an area of soft rock.
2. The softer rock in eroded more (by hydraulic action and abrasion) than the harder rock creating a "step" in the river
3. As the river flows over the step more and of the softer rock is eroded
4. Eventually a steep drop is created which forms a waterfall
5. The hard rock is undercut by erosion and it eventually becomes unstable and collapses
6. The collapsed material swirls at the foot of the waterfall where it erodes the softer rock by abrasion. This creates a deep plunge pool
7. Overtime more undercutting causes more collapses which make the waterfall retreat leaving behind a gorge - 54What is an interlocking spur and why are they formed?An interlocking spur is when hillsides make a zip shape
This happens because....
1. In the upper course of a river, the main erosion is vertical erosion. This creates steep sided V-shaped valleys
2. The rivers aren't powerful enough to erode laterally therefore they have to wind around the high hillsides that stick out into their paths on either side - 55What are Meanders and Where are they found?Meanders are large bends in the river
They are found in the middle and lower courses of a river - 56How are meanders formed?1. The current is faster on the outside of the bend. This is because the water is deeper therefore there's less friction to slow the water down.
2. So more erosion (hydraulic and abrasion) takes place on the outside bend, forming river cliffs
3.The current is slower on the inside bend. This is because the water is shallower therefore there's more friction to slow the water down - 57How are oxbow lakes formed?1. Erosion causes the outside bends to get closer until there's only a small piece of land left between the bends (called the neck)
2. The river breaks through this land,usually during a flood and the river flows along the shortest course
3. Deposition eventually cuts off the meander , forming an oxbow lake. - 58What are Leeves?Leeves are natural embankments (raised bits) along the edges of a river channel
- 59How are Leeves formed?1.During a flood, eroded material is deposited over the whole flood plain
2. The heaviest material is deposited closest to the river channel, because it gets dropped first when a river slows down
3.Overtime, the deposited material builds up, creating leeves along the edge of the channel - 60What is a Delta?A Delta is a low-lying area where a river meets a sea or a lake
- 61How are deltas formed?Deltas are formed when a river meets a sea or a lake....
1. Rivers are forced to slow down when they meet a sea or a lake
This causes them to deposit the material they are carrying.
2. If the sea doesn't wash away the material, it builds up and the channels get blocked
This forces the channel to split up into lots of smaller rivers called distributaries
3. Eventually the material builds up so much that a low-lying area of land called deltas are formed - 62Which physical factors affect river landscapes and sediment load?1. Climate
2. Geology
3. Slope Processes - 63Explain Climate1. Rivers in wetter climates have a higher discharge. This is because more water is entering the river channel
2. The higher discharge increases the rate of erosion- if a river has higher volume of water it has more power to erode the river banks and bed. This adds material to the rivers load
3. It also shapes the landscapes forming V-shaped Valleys in the upper course (vertical erosion) and wide flat flood plains in the lower course (lateral erosion)
4. Transportation also increases when there's a higher discharge because the river has more energy to carry material
5. Weathering increases the river's sediment load and can affect the shape of the landscape, e.g. freeze-thaw weathering makes rockfall more likely - 64Explain Geology1. Rivers flowing through areas of hard rock have a slower rate of erosion, this is because hard rocks are more resistant
This means that the river will have a low sediment load
2. Areas of softer rock will experience more erosion- this adds more materials to the river's sediment load
3. Landscapes with more resistant rock tend to have steeper valley sides
Landscapes with less resistant rock tend to have gentle sloping valley sides
4. Waterfalls form where there is an area of hard rock on top of an area of soft rock
5. Interlocking spurs form where softer rock is eroded first, leaving areas of harder rock jutting out (forming a zip shape) - 65Explain Slope Processes1. Vertical erosion by rivers makes the valley sides steeper which increases the movement of material down the slope
2. Mass movement e.g. slumping adds large amounts of materials to the river's load.
Mass movements are more likely during colder weather (freeze-thaw weathering loosens the material) and during periods of intense rainfall (the saturated ground becomes heavier and less stable)
3. Soil creep is when soil particles move down the slope because of gravity. This is caused by the expanding and contraction of the soil.
Water adds weight to the soil making it expand- this causes it to move down the slope
When the soil dries out it contracts
Soil creep can add lots of fine material in the river's load - 66What is river discharge?River discharge is simply the volume of water that flows in the river per second
It is measured in cumecs- cubic metres per second (m^3/s) - 67What is Lag Time: Rising Limb: Falling Limb and Peak DischargeLag Time: The delay between the peak discharge and peak rainfall
Rising Limb:: The increase in river discharge as the rainwater flows into the river
Falling Limb: Decrease in river discharge as the river returns to normal level - 68What is lag time caused by?Lag time happens because most rainwater doesn't land directly in the river channel- there's a delay as rainwater gets to the channel
It gets there by flowing quickly overground (surface runoff) or by infiltrating into the ground and flowing slowly underground - 69What are the physical factors that affect lag time, discharge and shape of hydrograph:1. Geology
2. Soil Type
3. Slope
4.Drainage Basin Type
5. Antecedent Conditions - 70Explain: Geology Soil Type and SlopeGeology: water can not infiltrate into impermeable rocks, so there's more surface runoff.
Soil Type: most impermeable soils (e.g clay) can't absorb as much water as sandy soils, which increases surface runoff.
Shallower soils also become saturated quicker than deeper soils which increases surface runoff
Slope: The steeper the slope, the less infiltration and the higher the surface run off - 71Explain Drainage Basin and Antecedent Conditions:Drainage Basin: Circular drainage basins have a shorter lag time and higher discharge than narrow basins because water reaches the main river channel at the same type.
In a narrower basin, water from the far end of the basin takes a long time to reach the main channel
Antecedent conditions: previously wet and very cold conditions can increase surface run off because the water can not infiltrate into saturated or frozen soil - 72What are the human factors that affect lag time, discharge and shape of hydrograph?1. Urbanisation
2. Deforestation - 73Explain Urbanisation and Deforestation:Urbanisation: Most urban areas are covered in tarmac and concrete. Water can not infiltrate into impermeable surfaces which increases surface runoff
Gutters and drain quickly take runoff to rivers, which rapidly increases discharge
Deforestation: Trees take up water from the ground and store it, reducing runoff. Cutting down trees increases increases runoff and causes more water to reach the channel increasing discharge - 74Why is the risk of flooding increasing? Two main Factors1. Increasing Frequency of Storms
2. Land Use Change - 75Explain Frequency of Storms:1. The frequency of storms in the UK is increasing and this could be a consequence of global climate change.
2. It is thought that the storms are becoming more extreme- more intense rainfall is increasing the scale of floods events
3. More periods of wet weather mean that the ground is saturated making flooding more likely because water can no longer infiltrate into the ground - 76Explain Land Use Change:1.As the UK's population grows, there's more pressure to expand urban areas. This leads to an increase in impermeable surfaces such as concrete and tarmac which leads to rapid surface runoff
2. Removing vegetation and permeable surfaces means that water that would have been stored in the soil or plants and trees now flows quickly downstream
3. Lots of development e.g. house building, is taking place on flood plains. These areas are naturally prone to flooding and this increases the risk to developed areas
3. More people are living on flood plains which mean that more people are at risk of flooding if flood defences fail - 77How do floods threaten people?1. People can be killed or injured by floodwater
2. Roads, bridges and rail lines can be damaged or destroyed
3. Flood water is often contaminated with sewage, which can lead to a lack of clean drinking water
4. Possessions can be damaged or washed away
5.People can be made homeless as their properties are inundated or damaged
6. Businesses may be forced to shut down because of flood damage and disrupted power supplies. This leads to a loss of livelihoods - 78How do floods threaten the environment?1. Flood water is often contaminated with sewage and rubbish and therefore can pollute rivers damaging wildlife habitats
2. Farmland can be ruined by silt and sediment deposited after a flood
3. River banks are eroded, causing huge changes to the river landscape e.g widening the river channel and increasing deposition downstream
4. The force of floodwater can uproot trees and plants destroying animal habitats - 79What are the hard engineering processes used to protect the coast?1. Flood Walls
2. Embankments
3. Flood Barriers (Floodgates)
4. Flood Barriers (Demountable) - 80Explain Flood WallsFlood walls are artificial barriers built along the river banks.
Benefit:
They're designed to increase the height of the river bank, allowing the river channel to hold more water.
Costs:
They are very expensive
They can be unsightly and block the view of the river - 81Explain Embankments:Embankments are high banks that are built along or near the river banks
Benefits:
They stop the river flowing into built-up areas during a flood protecting buildings and infrastructure on the flood plain
They can be made from earth or other natural materials, making them less unsightly than flood walls
Costs:
They're quite expensive to build
There's a risk of severe flooding if the water rises above the level of the embankments or if they break - 82Explain Flood GatesFlood gates such as The Thames Barrier are built river estuaries to stop flooding from storm surges or very high tides.
Benefits:
They can be shut when there's a surge forecast to prevent flooding
They protect a large area of land e.g central London
Costs:
They are very expensive - 83Explain Flood Demountables:Demountable flood barriers provide temporary protection against flooding:
Benefit:
The barriers are only put up when there's a flood forecast
But they don't spoil the look of attractive locations
Cost:
They may not always be put in time
They are quite expensive to build - 84What are soft engineering examples of protecting the river?1. Flood Retention
2. River Restoration - 85Explain Flood Retention:Flood Retention is a strategy which involves maintaining the river's flood plain e.g. by not building on it.
Benefit:
It helps to slow floodwaters down and maintain the flood plain's ability to store water
No money has to be spent on building defences but it restricts development and can't be used in urban areas - 86Explain River Restoration:This involves making the river more natural e.g. by removing man made levees so that the flood plain can flood naturally
Benefit:
There's less risk flooding downstream because discharge is reduced
The river is left in its natural state so little maintenance is required
Costs::
River restoration can increase risk of local flooding especially is nothing is done to prevent major flooding
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- Flashcards on Geography GCSE Coasts, created by Britney Bullen on 31/05/2018.
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