River Flow Flashcards

1
Q

What is the velocity + energy of a stream controlled by?

A
  • gradient of channel bed
  • volume of water in channel (controlled largely by pptn in drainage basin)
  • shape of channel
  • channel roughness, inc. friction
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2
Q

What are the 3 main types of flow?

A
  • laminar
  • turbulent
  • helicoidal
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3
Q

What are the features of a laminar flow?

A
  • requires smooth, straight channel w low velocity
  • top + bottom layers slower due to friction
  • occurs on efficient rivers
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4
Q

What are the features of a turbulent flow?

A
  • requires high velocities + complex channel (meandering w pools + riffles)
  • causes vertical + horizontal eddies from obstructions in river + pressure imbalances
  • vertical turbulence creates hollows
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5
Q

What are the features of a helicoidal flow?

A
  • ‘corkscrew’ motion due to pressure differences on a meander
  • from high to low pressure: eroding outer banks + depositing sediment to inner bank (creating meander)
  • starts at thalweg: line/flow of max. velocity
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