GEOGRAPHY UNIT 1 TOPIC 6

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  • Created by: stelly_tn
  • Created on: 26-03-17 12:00
Details of Upper course of a river - U1 T6
Gradient - steep, Discharge - small, Depth - shallow, Channel Shape - narrow with steep sides, Velocity - quite fast, Valley Shape - steep sides
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Details of Middle course of a river - U1 T6
Gradient - less steep, Discharge - large, Depth - deeper, Channel Shape - flat with steep sides, Velocity - fast, Valley Shape - flat with steep sides
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Details of Lower course of a river - U1 T6
Gradient - shallow, Discharge - very large, Depth - deep, Channel Shape - flat floor, gentle sloping sides, Velocity - very fast, Valley Shape - flat with gentle sloping sides
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Features of Upper course of a river - U1 T6
Waterfalls, interlocking spurs
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Features of Middle course of a river - U1 T6
Meanders, floodplains
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Features of Lower course of a river - U1 T6
Meanders, floodplain, levees, ox-bow lakes
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What is freeze-thaw weathering? - U1 T6
When rainwater enters a crack in a rock, if it freezes it exerts pressure on the rock and can eventually break it into pieces.
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What is biological weathering? - U1 T6
Tree roots can penetrate cracks in rocks and split them apart
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What is chemical weathering? - U1 T6
Rainwater is slightly acidic and can dissolve some rocks, especially limestone and chalk
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What is soil creep mass movement? - U1 T6
Particles of soil slowly move down the sides of valleys under the influence of gravity
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What is slumping mass movement? - U1 T6
Valley sides are eroded by the river making the sides steeper and increasing the downward movement of material. Heavy rainfall can trigger this movement
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What is weathering? - U1 T6
The breakdown of rocks and minerals by physical and chemical processes
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What are the upper course landforms? - U1 T6
Pot holes, interlocking spurs, waterfalls, rapids, gorges
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How is a waterfall is made? - U1 T6
Soft rock, undercutting, overhang and plunge pool
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How is a v shaped valley made? - U1 T6
The river erodes down (vertical erosion), weathering breaks up material on the valley slopes, weathered material from the valley sides gets deposited in the river, the material is carried by the river and erodes riverbed through abrasion
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How is a gorge made? - U1 T6
When a waterfall retreats, it creates a gorge in front
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How are interlocking spurs made? - U1 T6
As the river erodes the landscape in the upper course, it winds and bends to avoid areas of hard rock. This creates interlocking spurs, which look a bit like the interlocking parts of a zip
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What are the middle course landforms? - U1 T6
Meanders, floodplain
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How are meanders made? - U1 T6
The river swings from side to side, the force of the water swinging directs the fastest current & force against the outside bank, forming a river cliff, the inside edge the current is slower & deposition of sand takes place, creating a slip-off slope
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How are floodplains made? - U1 T6
Flood plains are made by a meander eroding sideways as it travels downstream. When a river breaks its banks and floods, it leaves behind layers of alluvium (silt).
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What are the lower course landforms? - U1 T6
Ox-bow lakes, deltas, levees, large floodplains
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How are ox-bow lakes made? - U1 T6
Narrow neck of land is eroded, narrow neck is cut through and water takes quickest route, deposition seals off old meander and ox-bow lake dries up
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How are deltas made? - U1 T6
When a river reaches a lake or the sea the water slows down and loses the power to carry sediment Larry. The sediment is dropped at the mouth of the river. Some rivers drop so much sediment that waves and tides can't carry it all away.
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How are levees made? - U1 T6
River between two floodplains, when river floods sediments dropped at the edge to create a mound of sediment on each side, acts as flood defence
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What is abrasion? - U1 T6
When the rocks, sand and pebbles erode the river bed.
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What is attrition? - U1 T6
Attrition is the process where pieces of rock are transported through water and wear down the shore bed over time as a result of friction.
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What is hydraulic action?
Hydraulic action occurs when the motion of water against a rock surface produces mechanical weathering.
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What is solution? - U1 T6
The solution of a river is the final result of the erosion of the rocks that are in the river.
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What are the causes of flooding? - U1 T6
Heavy rainfall, snowmelt, long periods of rain, steep slopes, urbanisation, deforestation
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What is recession limb? - U1 T6
The recession limb extends from the peak flow rate onward
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What is peak discharge? - U1 T6
the highest point on the hydro graph when the rate of discharge is greatest
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What is lag time? - U1 T6
the time interval from the center of mass of rainfall excess to the peak of the resulting hydrograph
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What are the impacts of the York Floods? - U1 T6
Homes and businesses flooded, people evacuated, road and rail links cuts off, huge costs £1 to deal with and millions in insurance pay outs
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What were the existing flood defences in the York Floods? - U1 T6
Flood warning systems, sand bags for areas of risk, raised embankments
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What are the hard engineering methods of managing a river? - U1 T6
Embankment or levee, straightening of channel, dam built upstream, relief channel
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What are the soft engineering methods of managing a river? - U1 T6
Washlands, plant trees, planning, flood system warning
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What are the benefits and costs of a levee? - U1 T6
Benefit - stops flood water from spreading Costs - expensive, may burst or water may go everywhere
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What are the benefits and costs of straightening the channel? - U1 T6
Benefit - water flows away more quickly Costs - defers flooding, unsightly
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What are the benefits and costs of a dam? - U1 T6
Benefits - able to regulate and control flow Costs - expensive, can burst
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What are the benefits and costs of a relief channel? - U1 T6
Benefit - Takes over flow water Costs - expensive, disruptive to build
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What are the benefits and costs of washlands? - U1 T6
Benefits - Cheap, water can go somewhere, can be used for special habitats
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What are the benefits and costs of planting trees? - U1 T6
Benefits - tress reduce amount of water reaching river, provides habitats for wildlife Cost - land cannot be used for anything else
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What are the benefits and costs of planning? - U1 T6
Benefit - building restricted to areas with low risk of flooding Cost - may cause planning problems elsewhere
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What are the benefits and costs of flood warning systems? - U1 T6
Benefit - prepares people Cost - sometimes difficult to give warning
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Other cards in this set

Card 2

Front

Details of Middle course of a river - U1 T6

Back

Gradient - less steep, Discharge - large, Depth - deeper, Channel Shape - flat with steep sides, Velocity - fast, Valley Shape - flat with steep sides

Card 3

Front

Details of Lower course of a river - U1 T6

Back

Preview of the front of card 3

Card 4

Front

Features of Upper course of a river - U1 T6

Back

Preview of the front of card 4

Card 5

Front

Features of Middle course of a river - U1 T6

Back

Preview of the front of card 5
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