River landforms of the upper course Cambridge IGCSE Geography (9–1) revision
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In plain words
High in the hills, a river is small, steep and energetic for its size. It spends its energy cutting downwards, and the landforms it makes are narrow, steep and rocky.
7 things to know
- A V-shaped valley forms where the river erodes vertically. The steep sides are then worn back by weathering and by material slipping downhill.
- Interlocking spurs are ridges of hard rock that the river winds around, because it does not have the energy to cut through them.
- A waterfall forms where a band of hard rock lies over softer rock. The soft rock is eroded faster, by hydraulic action and abrasion, leaving the hard rock overhanging.
- The overhang collapses, and the fallen rock is swirled round at the base, deepening a plunge pool.
- The process repeats, and the waterfall retreats upstream, leaving a steep-sided gorge.
- Rapids are stretches of fast, rough water where the bed is uneven, because of alternating bands of hard and soft rock.
- Potholes are round hollows drilled into the river bed, where pebbles are swirled round by the current.
Worked example
Explain how a waterfall and a gorge are formed.
- The river flows over hard rock that lies on top of softer rock.
- The softer rock is eroded more quickly, by hydraulic action and abrasion, so the hard rock is undercut and overhangs.
- The unsupported hard rock collapses. The fallen blocks erode a deep plunge pool at the base.
- This repeats, so the waterfall moves back upstream, leaving a steep-sided gorge.
Tips and tricks
- In a formation question, go step by step and name the erosion processes. "The rock is eroded" is weaker than "the soft rock is eroded by hydraulic action".
- A labelled diagram can earn the marks faster than a paragraph. Label the hard rock, the soft rock, the overhang and the plunge pool.
It lands in your notebook with its questions as flashcards.
River landforms of the upper course: 5 questions and answers
These are the quiz’s questions. Do the quiz first, then come back here for the ones that got you.
What shape is a river valley in the upper course?
The river erodes downwards.
Where does a waterfall form?
The softer rock is worn away faster.
What is left behind as a waterfall retreats upstream?
A steep-sided, narrow valley.
What is a plunge pool?
Falling water and swirling rocks deepen it.
How is a pothole formed?
The pebbles drill downwards by abrasion.
Quiz
5 questions
Tap an answer and you’ll see straight away whether it’s right, and why.
Worksheet
3 questions, 8 marks. Write your answers on paper, then check them.
River landforms of the upper course
Cambridge IGCSE Geography (9–1) 0976 · 8 marks · papermunch.org
Name ______________________________ Date ______________
Describe the shape of a river valley in the upper course.[2]
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It is V-shaped, with steep sides and a narrow floor almost filled by the river.
Explain how a pothole is formed.[4]
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Pebbles are trapped in a small hollow in the river bed. The current swirls them round. They drill into the bed by abrasion, making the hollow deeper and rounder.
Explain why interlocking spurs form.[2]
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In the upper course the river does not have enough energy to erode through ridges of hard rock. It winds around them instead.
Answers: River landforms of the upper course
- 1. It is V-shaped, with steep sides and a narrow floor almost filled by the river.
- 2. Pebbles are trapped in a small hollow in the river bed. The current swirls them round. They drill into the bed by abrasion, making the hollow deeper and rounder.
- 3. In the upper course the river does not have enough energy to erode through ridges of hard rock. It winds around them instead.