River Landscapes

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  • Created by: RGV17
  • Created on: 19-09-16 17:25
What do erosion processes require?
The flow of water.
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What is hydraulic action?
When the force of the river against the banks cause air to be trapped in cracks.
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What is corrasion?
When rocks carried along by the river wear down the river bed.
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What is corrosion?
When soluble particles are dissolved into the river.
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What is attrition?
When the rocks being carried by the river smash together and break into smoother particles.
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What is physical weathering?
When the water gets into the crack. The water freezes and expands. This opens up the crack in the rock. Rocks fall into pieces.
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What is biological weathering?
Animals and plants grow or dig under rocks or in cracks. The rocks are undercut by the movement. The rock is loosened and cracks appear. Rocks collapse or fall apart.
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What is chemical weathering?
Rainwater contains weak acid. Acid attacks the rock. The rock begins to wear away and break up. The rock is dissolved or weakened.
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What is slumping?
It occurs on river banks. There's rotational slipping. A large area moves down a slope. It leaves behind a curved surface. It absorbs and saturates. It weakens and falls down due to gravity.
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What is soil creep?
It's the downhill movement of soil. Gravity pulls water which contains soil. The movement is not visible but it's faster in rain. It creates slopes that are like ripples which are called terracettes.
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What is a source?
Where the river starts.
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What is a tributary?
Where the river is joined by smaller rivers.
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What is a confluence?
The junction between rivers.
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What is the mouth?
Where the river meets the sea.
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What is a watershed?
The boundary of the drainage basin.
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What is a meander?
A river with a bend.
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How are V-shaped valleys formed?
95% of a river's energy is used to overcome friction. The remaining 5% is used to erode downwards and due to physical weathering, rocks will fall, creating a V-shape.
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How are interlocking spurs formed?
This happens when the rivers avoid hard or resistant rocks by eroding around it.
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Explain how a waterfall is created(Part 1).
A river meets less resistant rock. The softer rock is eroded away quickly. Abrasion causes undercutting. The more resistant rock overhangs and collapses on the river bed. The rock causes abrasion of the river bed.
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Explain how a waterfall is created(Part 2).
Hydraulic action creates a deep plunge pool. The process is retreated and the waterfall retreats upstream. A steep-sided river valley is created(gorge).
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What are the human causes of flooding?
Ploughing up and down slopes rather than around them. If vegetation had been removed, there's less interception and water will move quickly to the river. Dams may burst which causes excess water in channels.
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What are the physical causes of flooding?
Large amounts of rain day after day, the ground saturates. Silted river beds make channels smaller. A rapid thaw- sudden rise in temperature. Long period of hot, dry weather makes the soil hard. A cloudburst in a thunderstorm. Steep valley slopes.
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What are the physical/human causes of flooding?
Impermeable rocks- the rainwater can't soak into rocks and flow more quickly to rivers. A town on a floodplain, storm drains allow water to move into the river at a greater speed.
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What is the date and location of the Pakistan flood?
2010. Indus river.
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What are the environmental effects of the Pakistan flood?
80% of reptile's and small mammal's habitats affected in Swat river catchment. Unprecedented monsoon rains. Mudslides occurred in mountainous areas.
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What are the human effects of the Pakistan flood?
1781 fatalities. £1.5 billion agriculture loss. 1.9 million houses damaged. Infrastructure demolished. Food shortages.
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What is the date and location of the UK flood?
January 2014. Thames river.
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What are the environmental effects of the UK flood?
Wettest January. Many animals could be poisoned by redistributed pesticides and toxic chemicals. Flood contamination linked to lead poisoning.
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What are the human effects of the UK flood?
1,135 homes flooded. Clear-up costs could reach £1bn. 14 severe flood warnings. 1.5 million people live in the floodplain. Expenses of relocating businesses. Losses in tourism industry. Railway station at risk.
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What are the number of ways the effects of flooding can be reduced in forecasting and education ideas?
Householders are warned about floods through the Met Office predicting the likelihood of a flood, information given through weather forecasts and news broadcasts. Advising householders to be proactive and ring a flood hotline number.
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What are the forecasting and education ideas in river management?
Environment Agency website- information on the likelihood of a flood as a system of warning codes. There's a number of websites run by the government to give advice to people living in flood-prone areas, e.g. www.direct.gov.uk
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What are the planning and building design ideas in river management?
Local authorities give out planning permission for houses, not done in flood-prone areas unless there's a flood risk assessment. If houses are built in flood-prone areas, it can cost from £3,000 to £10,000 in protecting a house.
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What were the things Doncaster council did after a severe flood?
They carried out a series of flood resilient repairs: Waterproof plaster and wall covering, chemical waterproofing of concrete floors and waterproof medium density fibreboard used instead of wood.
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What can be done to house to reduce the effects of a flood in planning and building design?
Moving electricity sockets higher up the walls. Replacing doors with ones that are lightweight and can be moved easily. Concrete floors instead of wooden ones so they don't rot.
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What are embankments?
Raised banks along the river made of concrete or soil.
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What are the advantages of embankments?
Concrete embankments are effective at stopping bank erosion. Earth embankments provide habitats for plants and animals. Can be used as a path for pedestrians.
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What are the disadvantages of embankments?
Concrete embankments are ugly and spoil the view.
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What is channelisation?
Making the river water wider and deeper, lining the river bed and banks with concete.
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What are the advantages of channelisation?
Effectively protects immediate areas because water is moved away quickly.
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What are the disadvantages of channelisation?
Greater risk of flooding downstream, water is carried there faster.
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What are flood relief channels?
The channel course of the river altered which diverts floodwaters away from settlements.
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What are the advantages of flood relief channels?
Makes the people who live close to the main river safer as the flood water is diverted into the relief channel. Can be used for water sports.
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What are the disadvantages of flood relief channels?
Large amount of land needed which might be difficult to purchase, particularly if it is productive farmland. Greater risk of flooding downstream, water is carried there faster.
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What are dams?
Solid structures built across the river to stop the river(reservoir).
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What are the advantages of dams?
Long lasting. Stored water can be used to generate hydroelectric power or for recreation.
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What are the disadvantages of dams?
Building a dam is very expensive. Settlements and agricultural land may be lost when the river valley is flooded. Unnatural and visually intrusive.
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What are flood walls?
Walls alongside a river to stop flooding.
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What are the advantages of flood walls?
Can be used in areas where space is limited. Easily and quickly in pre-constructed.
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What are the disadvantages of flood walls?
They have to be assembled very well so that water doesn't get through joints. Extremely expensive. Are sometimes not built high enough.
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What are storage areas?
A large depression close to the river that will fill with water if the river overflows.
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What are the advantages of storage areas?
Natural looking, apart from possible concrete entrances gates/walls around the edge. Doesn't damage the environment.
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What are the disadvantages of storage areas?
Need a large area of land that is not being used. Only come into use when the river has flooded.
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What is floodplain zoning?
Classification of each part of a floodplain based on risk of floods and this determines what is built on it.
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What are the advantages of floodplain zoning?
A very cheap way of reducing the risk of damage to property. Floodplain hasn't been built on, so surface runoff is less likely to cause flooding. Reduces impact of flooding and building damage is limited.
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What are the disadvantages of floodplain zoning?
Enforcing planning regulations and controls may be harder in LIC's. Resistance to restricting developments in areas with a shortage of housing.
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What are washlands?
The river is allowed to flood naturally in wasteland areas, to prevent flooding in other areas like settlements.
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What are the advantages of washlands?
The deposited silt may enrich the soil, turning the area into agricultural land. Very cost effective as nothing is built.
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What are the disadvantages of washlands?
Large areas of land can't be built on. Productive land can be turned into marshland. Potential land can be turned into marshland. Potential wetland site for birds and plants.
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What are warning systems?
Informs people of the current situation of the flood.
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What are the advantages of warning systems?
A very cheap system. Electronic communication is a very effective way of informing people. People can move valuable belonging to a safer place.
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What are the disadvantages of warning systems?
The sirens could be vandalised, so are tested annually. Might not provide enough time for residents to prepare.
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What is afforestation?
Planting of trees on the floodplain which interferes with the run-off.
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What are the advantages of afforestation?
This is a relatively low cost option. Soil erosion is avoided as trees prevent rapid run off after heavy rainfall. Very sustainable. Improves the quality of the environment.
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What are the disadvantages of afforestation?
Dense tree plantations spoil the natural look of the landscape. It increases fire risks because of leisure activities that may take place. Conifers can make the soil acidic.
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What are the types of hard engineering that are used on River Nene?
In 2002, 450m clay flood embankment built in Weedon. A flood retention reservoir has been built at Billing. At Foot Meadow 4m high floodwalls have been installed. The river channel capacity at Upton was increased by building earth embankments.
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What are the types of soft engineering that are used on River Nene?
In 2003, the warning system was upgraded. A washland around Upton.
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What is Walton-on-the-Naze?
A coastal town in Essex(South-East England).
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What is the situation of the coastal defences in Walton-on-the-Naze?
It's protected by coastal defences but the spit or naze isn't protected. The longshore drift is moving south to north which decided what area will be protected.
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Why are the cliffs receding in Walton-on-the-Naze?
The cliffs are receding quickly because of the rock types that make up the cliff such as London Clay and Red Crag which erode easily. The cliffs also suffer from slumping which makes the defence of the area more complex.
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Give information on the seawall used in Walton-on-the-Naze.
It's located at the bottom of the cliff, the southern part of coastline. It was created in 1977. It was to protect properties of the cliff and protects the London Clay. It managed to control the erosion.
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Give information on the groynes used in Walton-on-the-Naze.
It's located in the southern part of the coastline. Built in 1977. It was to prevent longshore drift. It kept the beach place but wasn't effective alone.
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Give information on the cliff regrading used in Walton-on-the-Naze.
It was used in the northern part of the town. Built in 1977. It is used to produce a gentler slope and to help planting vegetation.
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Give information on the rip-rap used in Walton-on-the-Naze.
It's located around the town. Built in 1988. It is used to prevent erosion of the coast in front of the tower. It has slowed down the erosion but hasn't stopped it.
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Give information on the beach replenishment used in Walton-on-the-Naze.
It's located at the beach in front of the cliff. Built in 1988. It's used to recover/replenish the beach so it will last longer. Majority of the material had been removed by longshore drift.
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Other cards in this set

Card 2

Front

What is hydraulic action?

Back

When the force of the river against the banks cause air to be trapped in cracks.

Card 3

Front

What is corrasion?

Back

Preview of the front of card 3

Card 4

Front

What is corrosion?

Back

Preview of the front of card 4

Card 5

Front

What is attrition?

Back

Preview of the front of card 5
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