Geography - Water on the Land

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What does the long profile show?
How the gradient/steepness changes over the different courses.
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What does the cross profile show?
What the cross section of a river looks like.
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Describe the upper course of a river?
Steep Gradient, v shaped valley, steep sides. Narrow, shallow channel.
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Describe the middle course of a river?
Medium gradient, gently sloping valley sides. Wider, deeper channel.
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Describe the lower course of a river?
Gentle gradient, very wide/ almost flat valley. Very wide, deep channel.
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What does vertical erosion do?
Deeepens the river valley, making it V-shaped. Dominant in upper course.
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What does lateral erosion do?
Deeepens the river valley. Dominant in midlle and lower courses.
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Hydraulic Action?
Force breaks rock particles wasy from channel.
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Abrasion?
Rocks scrape/rub channel, wearing it away.
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Attrition?
Rocks smash into eachother forming smaller fragments.
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Solution?
Water dissolves rocks.
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Traction?
Large particle pushed along the bed by force.
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Suspension?
Small particles carried along by water.
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Saltation?
Pebble sized particles bounce along river bed by force.
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Solution
Soluble materials are dissolved in water and carried along.
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What is deposition?
When a river drops the eroded material it's transporting.
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Why does river slow down to cause deposition?
1. water volume falls 2. amount of material increases 3. water is shallower 4. river reaches mouth
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On a meander where is teh current fastest?
On the outside of the bend.
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Where does erosion take place?
On the outside of the bend.
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Where is the eroded material deposited?
On the inside of the bend.
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How do waterfalls form?
The river flows over soft rock and hard rock. The soft rock erodes more quickly, ceating a step. The water going over the step erodes the soft rock even more creating a steep drop called a waterfall.
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How do gorges form?
Hard rock is undercut and becomes unsupported and collapses. More undercutting and collapse happen causing waterfall to retreat, forming a gorge.
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How is a plunge pool formed?
Colapsed rock erodes soft rock by ebrasion.
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What is a flood plain?
A wide valley floor on either side of the river wich occasionally gets flooded.
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What are levees?
Natural emankments along edges f a river channel formed when deposited material builds up along edges of a river
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What is river discharge?
The volume of water that flows into a river per second.
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What do hydrographs show?
How discharge at a certain point chages over time.
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Peak discharge?
Highest discharge.
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Lag time?
Delay between peak rainfall and peak discharge.
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When does the rising lim increase?
When rain flows into river.
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When does the falling lim decrease?
When river returns to it's normal level.
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What are the factors of river discharge?
Amount of rainfall, previous weather conditions, land use, temperature, rock type (permeable increases), relief (how the height of the land changes.
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What physical factors cause flooding?
Prolonged rainfall, snow melt, heavy relief and relief 9if steep, will increase)
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What human factors cause flooding?
Deforestation and building construction (made of impermeable material).
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Name two types of hard engineering?
Dams/reservoirs and channel straightening
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Name four types of soft engineering?
Flood warning, preperation, floof plain zones and do nothing.
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What are dams and reservoirs and what are the avantages and disadvantages?
Dams are bulit across upper course and reservoirs are bult behind the dame. They store water and genterate HEP altough are espensive, can flood existing settlements and materials are deposited.
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What is channel straightening and what are the advantages and disadvantages?
The course is straightened, meanders are cut out, Sometimes artificial straight channels are created. It moves water out of area quick however flooding can still happen downstream where water is flowing fast.
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What are flood warnings and what are the advantages and disadvantages?
The enviromental agency warns people baout flooding through tv, radio and newspapers. It gives people time to move possessions upstirs or evacuate although it is difficult to get insurance after plus some people can't access the sources.
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What is preperation and what are the advantages and disadvantages?
Building are modified and people keep important items in handy places. People know what to do and less buildings are damaged however it gives people a false sense of security and is expensive.
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What are flood plain zones and what are the advantages and disadvantages?
They are restrictions to prevent buildings on parts of a flood pliang meaning impermeable surfaces aren't created although this is no help to areas already built on.
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What are the advantages and disadvantages of doing nothing?
The farmland is made more fertile however there is al ot of damage.
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Other cards in this set

Card 2

Front

What does the cross profile show?

Back

What the cross section of a river looks like.

Card 3

Front

Describe the upper course of a river?

Back

Preview of the front of card 3

Card 4

Front

Describe the middle course of a river?

Back

Preview of the front of card 4

Card 5

Front

Describe the lower course of a river?

Back

Preview of the front of card 5
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