![]() 7 July 2020 / in AQA GCSE Geography, Landforms of river erosion, Rivers / by Anthony Bennett Find out more about meanders and oxbow lakes. The term is sometimes used synonymously with slip-0ff slopes although the term slip-off slope is used to refer to the cross section and the term point bar is used to refer to the aerial view. Draw a simple diagram to show the main features of a meander.They show the former positions of a meander during its downstream migration.They are crescent-shaped and located on the inside of a stream bend of meanders. ![]() There is a differentiation in flow speeds within a meandering river channel that produces areas of erosion and deposition. The bends in the river will migrate back and forth within the river valley. A point bar is a depositional feature made of alluvium that accumulates on the inside bend of streams and rivers below the slip-off slope. Meandering Rivers are located on flat terrain that reduces the flow speed of water, allowing the river to curve or 'meander'.The lateral erosion of the meanders and their migration widen the flood plain.This causes meander to migrate down the valley.The greater erosion of the concave bank occurs just downstream of the axis of the meander bend, because the course of the maximum velocity zone in the channel does not reflect the meander shape.Over time a small river beach or runoff slope builds up on the inner bend.This increased friction further reduces the velocity (thus further reducing energy), encouraging further deposition.the inner bend water is slow flowing, due to it being a low energy zone, deposition occurs resulting in a shallower channel.The lateral erosion results in undercutting of the river bank and the formation of a steep sided river cliff these cliffs are also known as bluffs.The flow speed in the channel varies with the geometry of the meanders. A meandering river channel has curves that meander back and forth on a gently sloping floodplain. There also vertical erosion which deepens the channel, which reduces friction and increases in energy results in further erosion. Meandering rivers have a low gradient and thus slower flow, and usually have a high proportion of suspended sediment relative to the amount of bedload.It erodes this bank laterally by attrition and hydraulic action.Water flows fastest on the outer bend (concave bank) of the river where the channel is deeper and there is less friction.
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