Thursday, 18 April 2013

The Genesis of a Meander

Pools are are areas of deeper calmer water with greater erosion and where the river flows faster due to reduced friction.
Meandering River Wharfe

Riffles are wide shallow areas of the river where water 'ripples' over pebbles beds with protruding rocks.

As these pools and riffles enlarge, the river will be propelled by centripedal force to twist round the riffles thus starting the side to side flow of the river. Erosion occurs on the outside of the bend, while deposition occurs on the inside.

All rivers take the path of least resistance to maintain theire maximum velocity (thalweg).

Outside of the bend:

  • Fastest flow
  • Lateral erosion
  • Hydraulic action
  • Undercutting of the alluvial materials of the river's floodplain
  • Abrasion
  • Deeper
  • River cliff

Inside of the bend:

  • Deposition
  • Shallow
  • Slowest flow
  • Slip off slope/point bar
  • Low energy

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