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Physical Geography Revision

Percolation > From soil into rocks.

Groundwater > Flow through rocks and cracks in rocks.

Infiltration > Flow from surface into soil

Throughflow > Flow along layers in soil.

Channel Catch > Rainfall from atmosphere into channel (directly).

Channel Flow > Water that flows through the river…

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Valley Cross Profile

Upper Course

Steep Sides
Narrow Bottom
V Shape
Vertical Erosion

Middle Course

Wide Valley
Valley Bluffs
Flat land
Lateral Erosion

Lower Course

Wide flat floodplain
Hard to locate valley sides
Lack of erosion, higher deposition


Found in the upper course but also at the mouth (isostatic…

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At times of higher flow water swings around one side of a riffle (centripedal
force) undercutting the outer bank on the surface before depositing this
sediment on the inner bank downstream.

In this way an outer concave river cliff is formed and a beach or point bar with a

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The valley becomes more asymmetrical, with steep cliffs on the outer
bends and gentler slip-off slopes on the inner bends.
With rapid incision, where downcutting (or vertical erosion) dominates
the valley is more symmetrical, with steep sides and a gorge-like
appearance. These are described as entrenched meanders.

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Causes of Bangladesh Floods 2007

Snowmelt ­ Brahmaputra annual discharge is 19,300 cubic metres per second.
With snowmelt in springtide it increases to 100,000 cubic meters a second. The
Gangstri glacier in the Indian Himalayas feeds the Ganges and is retreated at
25% each year leading to increased snowmelt.


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Effects of Bangladesh 2007 Floods

Social ­

Deaths in excess of 2000.
959 died as a result of diarrhoea, landslides, snakebites and respiratory
9 million homeless.
Damage to infrastructure including 3,000 km of earthen roads and 400km
of paved roads destroyed.

10-25 million people migrated into cities such as…

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Bangladesh Responses


The World Food programme sent energy biscuits for 400,000 people.
The CPP (Cyclone Preparedness Programme) was set up in 1970. It is a
warning system, which uses Asia's largest radio network linking with 143
radio stations. Radio warnings are relayed by 33,000 village-based
volunteers using megaphones and…

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Causes of Carlisle, Cumbria January 2005 Flood.

Carlisle Causes

Town developed on the River Eden floodplain.
Low pressure storm event caused heavy rainfall ­ two months rainfall
released in 24 hours.
Large, wide shallow floodplain.
Confluence of 3 rivers ­ Petteril, Eden and Caldew.
Ground already at it's saturation point…

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Flood Management ­ Ottawa Canada

Steep topography ­ funnel shaped basin.

Discharge increases due to snowmelt.

Peak is in Mid April ­ unregulated flows from southern tributaries cause
water to buildup as there is still ice in the river. (Snowmelt causes the rise in

Peak in Early May…

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Flood Management ­ Three Gorges Dam ­ China


2km long, 60 storeys tall.
4,000 workers.
17 years.
Produce over 20,000 MW of power. Twice all of UKs nuclear produces.
Central China
Yangtze River
Holds back 22 billion cubic metres of water.
One major flood every 10 years on this…


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