Full set of revision notes for river landforms

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V-Shaped Valleys.
In the upper course of rivers the characteristically large-calibre sediment load
is usually only transported when the discharge has risen as a result of heavy rain
or snowmelt. At such times the bouncing and rolling of boulders and cobbles
may cause intensive vertical erosion, which in turn produces a relatively
steep-sided V-shaped valley profile. The exact shape depends on three factors:
Climate- sufficient water is required for the high discharge levels
needed to instigate vertical erosion in the channel and to aid mass
movement on the valley sides above the eroding channel.
Geology- the type of rock and its structure may tend towards very
steep sides (e.g. Carboniferous limestone) or gently sloping valley sides
(e.g. clays and shale's).
Vegetation- more vegetated slopes tend to bind soil better and may
lead to more stable valley sides.

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Interlocking spurs are also characteristic of the upper courses of rivers. These
form when the river winds around protrusions, hills or ridges of land (spurs)
which appear to interlock when views looking up or down valley. A wider valley
may develop in the middle course with a near flat floodplain may be marked
by prominent slopes known as river bluffs. The lower course of the river may be
characterised by a very wide, flat floodplain.…read more

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Waterfalls and rapids occur when there is a sudden change in the gradient of
the river as it flows downstream. Waterfalls are more dramatic features than
rapids and may be the results of:
A resistant band of rock occurring across the course of the river.
The edge of a plateau
The rejuvenation of the area, giving the river renewed erosional power
as sea levels fall.…read more

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Potholes are cylindrical holes drilled into the rocky bed of a river by turbulent
high-velocity water loaded with pebbles. The pebbles become trapped in
slight hollows and vertical eddies in the water are strong enough to allow the
sediment to grind a hole into the rock by abrasion. Attrition rounds and
smoothes the pebbles caught in the hole and helped to reduce the size of the
Potholes can vary in width from a few centimetres to several metres.…read more

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Floodplains are created as a result of both erosion and deposition, although the
accumulation of river deposits suggests that they are predominantly
depositional features. They are relatively flat areas of land either side of the
river, which form the valley floor in the middle and lower courses of river. They
are composed of alluvium- river-deposited silts and clays. Over time, a
floodplain becomes wider and the depth of sediment accretions increases.…read more


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