Meanders and Ox-bow Lakes

Question 1

What are meanders and how are they formed?

Answer 1

• A meander is a large bend in the river course.
• A meander is formed from both deposition and erosion.
• Lateral erosion on the outside bend takes place due to the water having high energy, creating a river cliff.
• Deposition on the inside bend takes place due to the water having low energy, creating a slip of slope. -This creates a horseshoe shaped bend known as a meander.

Question 2

River cliff?

Answer 2

A steep bank on the outside of a meander formed by erosion.

Question 3

Slip off slope?

Answer 3

A slope above the river formed by deposition

Question 4

Point bar?

Answer 4

Pebbles and boulders deposited on the inside of a meander

Question 5

Thawleg?

Answer 5

The line of fastest flowing water in a river

Question 6

Floodplain?

Answer 6

The flat land liable to flooding either side of the river

Question 7

Describe and explain how ox-bow lakes are formed?

6 marks

Answer 7

Water flows faster on the outside of the meander, called the thalweg, so it has more energy to erode the river bank. Therefore, the meander becomes narrowed to form a swan’s neck meander. Eventually the swan’s neck meander is eroded to form a cut-off meander. Deposition occurs where the water flows slower and has less energy so an ox-bow lake forms.

Question 8

What is a meander scar?

Answer 8

A meander scar is when the ox-bow lake completely fills with sediment.