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  • Created by: Katie_
  • Created on: 17-02-14 12:41
How waterfalls occur
-Waterfalls occur when a river crosses a bed of more resistant rock -Erosion of the less resistant rock underneath continues, undercutting the hard rock above it -The river’s energy creates a hollow at the foot of the waterfall, known as plunge pool
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How waterfalls occur (continued)
-The less resistant rock beneath is eroded more rapidly by abrasion and hydraulic action. This creates a ledge, which overhangs and collapses. -The waterfall takes up a new position, leaving a steep valley or gorge.
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Describe how rivers erode in their bed
-Corrosion as chemicals in the water dissolve minerals in the surrounding rock. -Abrasion as stones and pebbles are smashed into the river’s bed. -Collisions result in small fragments of rock being chipped off
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Describe how rivers erode in their bed (continued)
-Hydraulic Action, the force of the water breaks-up the channel.
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For a named river, describe two ways in which channel shape and characteristics change along a river profile
River Wharfe – The river bends in its middle course and each sharp bend is called a meander. In the upper course, the river winds gently around interlocking spurs and it has steep sides and the valley bottom is narrow.
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Identify one process of erosion. (1)
Hydraulic action
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Explain how two human actions can increase flood risk. (4)
-Urbanisation because towns and cities have more impermeable surfaces -Deforestation because removing trees reduces the amount of water intercepted and increases run-off.
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Identify two hard engineering flood management schemes. (2)
Build flood banks and increase the size of the river channel.
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Identify two soft engineering flood management schemes. (2)
Flood proofing and flood prediction/warning.
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Features of a river
Interlocking spurs, upper course, flow around valley side slopes called spurs -Waterfalls, upper course, when a river runs over alternating layers of hard and soft rock, rapids and waterfalls may form
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More Features of a river
Meanders, middle and lower course, The flow of a river swings from side to side, eroding the banks of the river forming large bends -Levees, lower course, when rivers flood
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More Features of a river
Ox-bow lakes, middle and lower course, as the river breaks through e.g. During a flood when the river has a high discharge and more energy, and the ends join, the loop is cut off from the main channel. The cut off loop is called an ox-bow lake
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More Features of a river
Flood plains, lower course, when the river floods, slows down and deposits the sediment it was carrying
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Other cards in this set

Card 2

Front

How waterfalls occur (continued)

Back

-The less resistant rock beneath is eroded more rapidly by abrasion and hydraulic action. This creates a ledge, which overhangs and collapses. -The waterfall takes up a new position, leaving a steep valley or gorge.

Card 3

Front

Describe how rivers erode in their bed

Back

Preview of the front of card 3

Card 4

Front

Describe how rivers erode in their bed (continued)

Back

Preview of the front of card 4

Card 5

Front

For a named river, describe two ways in which channel shape and characteristics change along a river profile

Back

Preview of the front of card 5
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