Factors affecting river flow and velocity.

Created by: hamishc
Created on: 24-04-16 13:21

What factors affect the type of flow?

Gravity (causing downstream flow), frictional resistance (opposing downstream flow)

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What is turbulent flow?

When the flow is turbulent, chaotic and eddying, provides upward motion which picks up particles (erosion), contributes to more deposition downstream.

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What are the conditions needed for turbulent flow?

Complex channel shapes such as pools, riffles and meandering bends, high water velocity, cavitation (when pockets of air explode under high pressure)

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What is Laminar flow?

The movement of water in a series of sheets, common in the bed in the lower course of the river. Causes little erosion but lots of deposition assuming high levels of sediment.

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What are the conditions needed for laminar flow?

Smooth straight channel, low velocity, shallow channels.

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What factors affect channel shape?

Hydraulic radius (higher the ratio, the more efficient the stream, and less frictional loss),

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What is channel roughness?

When objects like boulders and vegetation cause friction that slows down the velocity of the river. The higher the value, the rougher the bed.

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Other cards in this set

Card 2

Front

What is turbulent flow?

Back

When the flow is turbulent, chaotic and eddying, provides upward motion which picks up particles (erosion), contributes to more deposition downstream.

Card 3

Front

What are the conditions needed for turbulent flow?

Back

Card 4

Front

What is Laminar flow?

Back

Card 5

Front

What are the conditions needed for laminar flow?

Back

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Factors affecting river flow and velocity.