Rivers Flashcards

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Where are V - Shaped Valleys found?
Upper section of the river's course and close to the source.
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How are the V - shaped vallyes formed?
By the vertical down cutting of erosion
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What are interlocking spurs and where are they found?
The upper course of a river and are ridges of land that seem to interlock each other. The river has travel round these ridges.
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How are waterfalls formed and where are they found?
Found at the upper course of a river and are formed by a change in rock type. When a river comes into contact with less resistant rock the river will start to erode this away causing a change in gradient.
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Why do waterfalls retreat upstream?
When the softer rock is eroded this causes undercutting. Undercutting carries on until the harder rock above can no longer be supported so they collapse into the plunge pool. The material deposited in the plunge gets transported down stream. (Contin)
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What is a meander and where are they found?
They are bends in a river found in the middle to lower course due to there being much energy in these sections allowing a greater amount of erosion to take place.
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What happens on the outside and the inside of a meander bend?
On the outside: Current is deep and fast flowing causing erosion. On the inside: Increased friction so the river here is slower and dosent have much energy so material is deposited forming a slip off slope.
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What is an oxbow lake? And how are they formed?
Due to continued erosion of meanders causes the neck of the meander to get narrower. The river then erodes through the neck to find the fastest and shortest route causing a temp straight river. Deposition then occurs on the outside leaving the lake.
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What is a floodplain?
The flat land either side of river that are prone to flooding.
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What are flood plains good for?
Farming.
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What are leeves?
Banks on the side of the river that stoop flooding into the flood plain
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How are natural levees formed?
Excessive precipitation causes the river to bursts its banks. At this point the material in the water are deposited creating a natural embankment.
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Where are deltas found?
The lower course of a river.
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What conditions are needed for a delta to be formed?
1. High river sediment load. 2. Gentle gradient and this encourages sediment build up.
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How are delts formed?
They are formed where the amount of material is too great for the sea currents to remove it.
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Why does the river lose power when it reaches the sea?
The power of the waves.
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What are the 3 river rocesses?
1. Erosion. 2. Deposition. 3. Transportation
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What are the 4 types of transportation?
1. Traction 2. Saltation 3. Suspension 4. Solution
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What is traction and when does it occur in a river?
Traction is where large boulders roll along the river bed. It is most likely to occur in the river when it has its highest amount of energy. For example when there has been a lot of rain and the river level is high.
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What are the 4 processes that can erode a river?
1. Attrition 2. Hydraulic actin. 2. Corrosion. 3. Corrasion
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When does deposition occur in a river?
When the river loses energy so can no longer carry the load.
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What is a drainage basin?
An area of land drained by a river and its tributaries.
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What is the watershed?
The boundary between one drainage basin and another.
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What is the hydrological cycle?
The continuous recycling of water.
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What are the inputs of a drainage basin?
Precipitation
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What are the outputs of a drainage basin?
Rivers carrying it to the sea or evapotranspiration: the loss of moisture
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What are the stores of a drainage basin?
Above land: lakes, puddles, ice and snow. Benlow land: Soil and rocks (Aquifers) Interception: Plants
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What are the trasfers of a drainage basin?
1.Infiltration: The downward movement of water from the surface through the soil. 2.Surface run off
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What is through flow?
Where is transferred through the basin sideward.
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Why is river management needed?
To prevent flooding in large human populations and protecting valuable agricultural land.
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What are some soft engineering strategies for flood prevention from rivers?
1. Wetlands created and preserved to store excess water and provide habitats. 2.Afforestation in the basin to reduce surface runoff and provide water storage for evapotranspiration.
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What are some hard engineering strategies for flood prevention from rivers?
1. Artificial levees: Concrete is used to reinforce, strengthen and heighten the river channel. 2. Straightening: Increases the river power and directs the river away from high risk areas. 3. Dams: Store water to control river discharge
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Other cards in this set

Card 2

Front

How are the V - shaped vallyes formed?

Back

By the vertical down cutting of erosion

Card 3

Front

What are interlocking spurs and where are they found?

Back

Preview of the front of card 3

Card 4

Front

How are waterfalls formed and where are they found?

Back

Preview of the front of card 4

Card 5

Front

Why do waterfalls retreat upstream?

Back

Preview of the front of card 5
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