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Erosion
Erosion
occurs in all rivers. Erosion is the wearing away of the river bed,
river banks and channel. There are different types of erosion in a river:
Erosion
caused by water
Running
water is very powerful. The water from rivers and streams has a lot
of energy when it is travelling very fast. This energy can wear away
the sides and banks of a river's channel as well as the river bed. The
pressure of the water can also wear away the river bed to make a V-shaped
valley. Erosion from the water can create features like waterfalls
and rapids which are formed by the erosion
of soft rocks overlying a band of harder rock.
Erosion
caused by rocks and stones in the water
When a
river moves stones and rocks along its bed, the sides of the channel
and the river bed are eroded. As these stones and rocks move along,
they hit the river banks and the river bed, causing pieces of rock to
break off. This gradually erodes the river bed and channel sides, making
the river wider and deeper.
Evidence
of erosion
Signs
of erosion may often be seen in a river. Look for one or more of these
signs:
Exposed tree roots.
Cracks in the soil
in a river bank.
Clumps of grass
in the river.
The top part of
the river bank overhangs.
Brown or coloured
water.
Collapsed river
bank.
The photo
above shows six examples of erosion.
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