Question

The river channels in the lower course are wider than the upper course.

Answer 1

1. In the lower course of the river, the gradient is gentler than in the upper course.
2. The river has more energy and the volume amount of water is high.
3. In the lower course, there is more lateral (sideways) erosion.
4. The channel is wide and deep.
5. The river has less friction to overcome which means that the river can flow faster.
6. As the river erodes sideways, it swings from side to side forming large bends called meanders.
7. Erosion is the most dominant action of river in the upper course.
8. In the lower course, the river moving down stream across a broad, level plain is loaded with debris brought down from its upper and middle courses.
9. Therefore the river channels are wider in the lower course compared to the upper course.