River Capture

Question 1

Explain river capture

Answer 1

Headward erosion causes the river to become longer.

Abstraction occurs because of the difference in rate of erosion on either side of the watershed. It continues until gradients are the same.

The river flowing down the steeper gradient has more energy, erodes through the watershed and captures part of the river flowing on the side with the more gentle gradient.

Question 2

Headward erosion

Answer 2

Erosion upstream towards the source of the river.

Question 3

Abstraction

Answer 3

The process whereby a watershed becomes lower and its position shifts in the direction of the less energetic stream.

Question 4

Elbow of capture

Answer 4

Sharp change in the rivers direction, showing where capture took place.
A Knickpoint waterfall may be present at point of capture.

Question 5

Misfit stream

Answer 5

A river that is too small for its valley, caused by being robbed of its headwaters.

Question 6

Wind gap

Answer 6

A part of the valley left dry by piracy, may contain river gravels.