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V-Shaped Valleys
V-shaped valleys are formed in the upper course of a river.

Water flows quickly through a narrow channel with a steep gradient.

As it does so, it cuts downwards into the land ­ vertical erosion.

Formation of a V-shape Valley

1. Vertical erosion ­ in the form of…

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A waterfall is a sudden fall of water that occurs where there are rapid changes in gradient
in the rivers course.

They are most commonly found where there are marked changes of geology in the river
valleys ­ where hard rock meets softer rock.

The soft rock is eroded…

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Rapids are areas along the rivers course where water becomes more turbulent.

It is caused by a localised increase in gradient along the rivers gradient or where the river
flows over alternating bands of harder and softer rocks.

These are often linked in with pool and riffle sequences -…

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Potholes are round to oval shaped holes in the bedrock of a river bed.

They are created where sediment accumulates within naturally occurring small depressions
on the rock surface of the river bed.

Turbulent flow swirls the stones around in the depressions, widening and deepening them
through the prolonged…

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Meanders are large, sweeping curves in a river's middle and lower cours e.

They're formed by erosion and deposition.

Meanders form where alternating pools and riffles develop at equally spaced intervals
along a stretch of river.

Because the river channel is deeper in pools it's more efficient, so it…

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The combined process also creates the meanders' distinctive asymmetric cross-section.

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Oxbow Lakes
Oxbow lakes are formed when the neck of the loop of a meander is broken through, often
during flooding.

It is formed when a meander becomes very curved and eventually the neck will touch the
opposite side and the river will cut through the neck, cutting it off.…

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When a river is at bankfull stage they may spill over onto relatively flat adjacent land
known as floodplains.

There is an increase in wetted perimeter and reduction in hydraulic radius which results in
more frictional contact and lower velocities than water in the main channel.

These factors combine…

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Levees are natural, raised embankments formed as a river overflows its banks.

During a flood, material is deposited across the whole flood plain as the river loses velocity
and energy due to increased friction.

The heaviest material, e.g. sand and gravel is dropped first, closest to the river channel.…


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