River landforms of the middle and lower course Cambridge IGCSE Geography (9–1) revision
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In plain words
Further downstream the land is flatter and the river is much bigger. It now cuts sideways, swinging across its valley in great bends, and every so often it spills over and spreads mud across the land.
5 things to know
- A meander is a bend in a river. Water flows fastest on the outside of the bend, where it erodes the bank to form a river cliff. It flows slowest on the inside, where it deposits material to form a slip-off slope.
- An oxbow lake forms when the neck of a meander becomes very narrow through erosion. In a flood the river cuts straight through. Deposition seals off the old bend, leaving a curved lake.
- A floodplain is the wide, flat land on either side of a river. It is built from silt deposited each time the river floods, and widened as meanders move across the valley.
- Levées are raised banks along the sides of a river. When the river floods, the water slows as it leaves the channel and drops its heaviest material first, right beside the river.
- A delta forms where a river carrying a large load enters a sea or lake. It slows down and deposits material faster than waves and tides can remove it. The river splits into channels called distributaries.
Worked example
Explain how an oxbow lake forms.
- Erosion on the outside of two neighbouring meander bends narrows the strip of land, the neck, between them.
- During a flood, the river breaks through the neck and takes the shorter, straighter course.
- Deposition seals the ends of the old loop, which is left as an oxbow lake.
Tips and tricks
- Outside bend: fast, deep, erosion, river cliff. Inside bend: slow, shallow, deposition, slip-off slope. Learn it as two lists.
- Levées are natural. Banks that people build higher for flood protection are a kind of engineering, often called embankments.
It lands in your notebook with its questions as flashcards.
River landforms of the middle and lower course: 6 questions and answers
These are the quiz’s questions. Do the quiz first, then come back here for the ones that got you.
Where is erosion greatest in a meander?
The water is fastest there.
What forms on the inside of a meander bend?
Slow water deposits material.
What is a floodplain made of?
Each flood adds a new layer.
What are levées?
The heaviest sediment is dropped first, beside the channel.
What are the channels of a delta called?
The river splits as it crosses its own deposits.
What is left when a meander is cut off?
A curved lake beside the new, straighter channel.
Quiz
6 questions
Tap an answer and you’ll see straight away whether it’s right, and why.
Worksheet
3 questions, 9 marks. Write your answers on paper, then check them.
River landforms of the middle and lower course
Cambridge IGCSE Geography (9–1) 0976 · 9 marks · papermunch.org
Name ______________________________ Date ______________
Describe the differences between the inside and the outside of a meander bend.[4]
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On the outside the water is faster and deeper, and erosion forms a river cliff. On the inside the water is slower and shallower, and deposition forms a slip-off slope.
Explain how levées are formed.[3]
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When a river floods, water spills over its banks and slows down. It deposits the heaviest material first, next to the channel. After many floods this builds up into raised banks.
State two conditions needed for a delta to form.[2]
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The river must carry a large load of sediment. The sea or lake must have weak tides and currents, so the sediment is not carried away.
Answers: River landforms of the middle and lower course
- 1. On the outside the water is faster and deeper, and erosion forms a river cliff. On the inside the water is slower and shallower, and deposition forms a slip-off slope.
- 2. When a river floods, water spills over its banks and slows down. It deposits the heaviest material first, next to the channel. After many floods this builds up into raised banks.
- 3. The river must carry a large load of sediment. The sea or lake must have weak tides and currents, so the sediment is not carried away.