Question

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

Answer 1

Upper course - this is where the river starts and is usually an upland area. Slopes are steep - this can increase the velocity of the river after heavy rainfall, when discharge is high. The river channel is narrow and shallow here. The river's load is large in the upper course, as it hasn't been broken down by erosion yet. When discharge is high vertical erosion erodes the river bed and larger sediments are transported by traction.

Mid-course - here the gradient becomes less steep. The river channel gets deeper and wider as the bed and banks are eroded. The sediment load of the river gets smaller in size. Small meanders and a small floodplain can be found in this part of the river.

Lower course - the final course of the river is where the land is a lot flatter. The river's load is fine sediment, as erosion has broken down the rocks. The river channel is at its widest and deepest as it flows towards its mouth. Deposition is the main process in this part of the river, which creates large floodplains and deltas.

Answer 2

Answer:

The river channels in the lower course are wider than the upper course because at the upper course the speed is high and it starts to cut anything in its path and at the lower course, the speed is low so it starts to distribute in many directions and distribute useful sediments.

Explanation:

In the 'lower course', the river channel becomes deeper and wider. The velocity is often greater than the upper curse because the channel is highly efficient with low friction. The channel is almost semi-circular and much smoother because of 'deposits of sand' and mud. 'In the lower course', a river flows through wide, flat valley called flood plain.