Processes and landforms in the sediment transfer zone

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  • Created by: Jason
  • Created on: 08-01-12 11:19
  • As a river goes downstream it's energy level increases due to :
  • A more efficient channel shape. 
  • Smaller bed load particles that offer less resistance to low and increase velocity.  
  • Higher discharge because of the increased drainage basin area.  

There is smoother flow.  

Rivers in the transfer zone normally flow in alluvial channels and in valley's that are wider and less confined in the uplands.  

Meanders 

Can cause river cliffs due to lateral erosion and undercutting of the bank that takes place.  Flow is sinuous, causing deposition in low velocity areas and the development of alternate bars.  

Once formed, alternate bars deflect the flow against the opposite bank causing erosion.  

Channel curvature increases velocity and directs flow against outer bank.  

Point Bars 

They are semi-circular sand or gravel deposits located on the inner banks of meanders.  A depositional feature.  The sediments are sorted to coarser sediments nearest the channel on the inner bank, finer sediments furthest away.  

Flood plains are formed by erosion and deposition in meandering rivers.  This lateral erosion occurs along the outer cut bank and is most concentrated just downstream of the apex of curvature.  This erosion causes the meander to move down the river and across the valley.  Valley's are widened where meander contact valley sides.  The scars cause slumps.  

Alluvial fans

Alluvial fans are lobes…

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