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Rivers - Coggle Diagram
Rivers
Processes
Erosion
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Attrition
Loads knock against each other, breaking apart to form smaller loads
Hydraulic action
Air and water getting into cracks on sides of river, building up pressure, making the sides explode
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Factors which affect
Size and shape of load
Discharge of water
Gradient of riverx
pH of river
Human interference
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Deposition
Occurs when river flows down
e.g. flooding-energy is discipated along land
Makes river features
Hydrological cycle (On land)
Input: Water falls to Earth from precipitation
Storage: Vegetation stores the precipitation
Transfer:
Infiltraion-water moving into the soil
Overlandflow-along the surface
Throughflow-Water flowing through natural pipes in the soil
Output:
Evapotransperation-water evaporating or leaving through plant leaves
River features
Middle course
Oxbow lake
Rivers try to take straightest path
Meander gets too curved
Flood takes place, river water takes shortest path of flow, eroding a shortest path, changing the mainstream
Deposition happens over time forming the oxbow lake
Meanders
fatter and horizontally developed river
Difference in river speeds
Deposition happens on one side (slip off slope) while errosion on other (river cliff)
COntinues to happen, making a bigger meander
Lower course
Levees blocks water from overflow
at edge of river channel
when floods occur, heaviest load deposited on edge of river
Accumulation of deposited load
New amount of discharge
Floodplains
WHen Levees form, new amount of discharge in river
When excess discharge, river overflkows levee
Flooding the plain
Caqused by lateral erosdion from meanders
Upper course
Waterfall and gorges
Hard rock on top
River flow down from hard to soft, causing erosion on sift rock
Undercut is formed
Due to gravity, the hard rock will fall
Water fallin ginto plunge pool will erode the undercut even more by hydraulic action
Repeating the retreat of hard rock, forming gorges
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Causes and effects of flooding
Natural
Snow melt
Saturated ground
Human
Urbansiation
Deforestation
Poor drainage
Climate change
Dam failures
Effects:
Loss of life
Displacement
Disruption to services
Health issues
Property damage
Economic loss
Crop loss