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57 Cards in this Set
- Front
- Back
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Drainage basin |
The area of land drained by a river |
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Catchment area |
The area within the drainage basin |
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Watershed |
The boundary of a drainage basin |
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Source |
The start of a river |
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Confluence |
The point where two rivers or streams join |
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Tributary |
A stream or smaller river which joins to a larger stream or river |
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Mouth |
The point where the river comes to the end, usually when entering a sea |
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Hydraulic action |
The river forces air into cracks in the banks. This causes pressure which weakens the banks and starts to wear it away |
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Solution |
The smaller, soluble particles in the river start to dissolve into the water |
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Attrition |
Rocks smash into each other as they are carried by the river, leaving them smaller and smoother |
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Abrasion |
Rocks that are carried by the river start to erode the river bed and river banks |
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Long profile |
To give an overall view of the river from start to finish |
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Cross profile |
To show a small portion of the river, often in more detail |
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How is a waterfall formed? |
Harder rock on top of softer rock. Plunge pool forms due to erosion of softer rock. Overhang of harder rock falls down, leaving a waterfall |
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How is a meander formed? |
Water travels faster at the outside of the curve than the inside, causing erosion on the outside and deposition on the inside |
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How is an ox-bow lake formed? |
Meander becomes more extreme due to more erosion and deposition. The river then travels straight across instead though the meander, going straight across and leaving an ox-bow lake |
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How are levees formed? |
During a flood, sediment is deposited on the edge of the channel, leaving higher edges. After many floods, high levees build up |
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Features of the upper stage |
Valley, river winds around interlocking spurs, vertical erosion, very clean water, some waterfalls |
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Features of the middle stage |
Tributaries, meanders develop, load increases, confluences, deposition more obvious, less steep slope |
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Features of the lower stage |
Floodplains, almost flat land, less erosion, meanders and ox-bow lake, fast flowing, deltas form |
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River discharge |
The volume of water passing a given point in a river at any moment in time |
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Factors affecting river discharge |
Rainfall, temperature, rock type, land use (e.g. Urbanisation) |
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Factors causing floods |
Rainfall, snowmelt, deforestation, construction work |
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Hard engineering |
Building artificial structures aimed at controlling natural processes |
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River discharge |
The volume of water passing a given point in a river at any moment in time |
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Case studies of flooding |
Tewkesbury 2007 Bangladesh 2004 |
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Water stress |
Not enough water is available for a certain area |
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Causes of water stress |
Inadequate supply, poor water quality |
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Factors affecting river discharge |
Rainfall, temperature, rock type, land use (e.g. Urbanisation) |
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Factors causing floods |
Rainfall, snowmelt, deforestation, construction work |
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Hard engineering |
Building artificial structures aimed at controlling natural processes |
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Soft engineering |
Working with the natural river system to prevent floods |
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Examples of hard engineering |
Dams, reservoirs, straightening meanders, embankments |
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Examples of soft engineering |
Floodplain zoning, flooding some areas to prevent flooding in others |
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Dam |
An artificial structure designed to hold back water to create a reservoir |
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Reservoir |
An artificial lake formed behind a dam and used for water supply |
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Floodplain zoning |
Controlling what is built on the floodplain so that areas that are at risk of flooding have low-value land uses |
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River discharge |
The volume of water passing a given point in a river at any moment in time |
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Case studies of flooding |
Tewkesbury 2007 Bangladesh 2004 |
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Water stress |
Not enough water is available for a certain area |
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Causes of water stress |
Inadequate supply, poor water quality |
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Effects of flooding |
Loss of power or water, damaged houses and possessions, loss of businesses, injury or death |
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Response to flooding |
Rescuing people, rebuilding houses, distributing supplies, temporary accommodation |
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Factors affecting river discharge |
Rainfall, temperature, rock type, land use (e.g. Urbanisation) |
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Factors causing floods |
Rainfall, snowmelt, deforestation, construction work |
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Hard engineering |
Building artificial structures aimed at controlling natural processes |
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Soft engineering |
Working with the natural river system to prevent floods |
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Examples of hard engineering |
Dams, reservoirs, straightening meanders, embankments |
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Examples of soft engineering |
Floodplain zoning, flooding some areas to prevent flooding in others |
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Dam |
An artificial structure designed to hold back water to create a reservoir |
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Reservoir |
An artificial lake formed behind a dam and used for water supply |
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Floodplain zoning |
Controlling what is built on the floodplain so that areas that are at risk of flooding have low-value land uses |
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Boscastle August 2004 floods |
Flooding caused by heavy rainfall and saturated ground Boscastle situated in a valley River channel has now been made deeper and drains have been improved |
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Causes of Bangladesh 2004 floods |
Monsoons and cyclones Low land and melted snow from Himalayas Deforestation and urbanisation |
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Responses to Bangladesh 2004 floods |
Food aid from around the world Water purification tablets Embankments, flood shelters, and dams built Reduce deforestation Expensive - not always successful |
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Areas of water stress/deficit |
South East water Thames water Severn Trent water |
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How is water being conserved? |
Devices in toilet cisterns to reduce water use Rainwater collected and used Bath water recycled to flush toilets |
