What are the features of the middle/lower course?

The middle course of the river has more energy and a higher volume of water. The gradient here is gentle and lateral (sideways) erosions has widened the river channel. The river has also deepened. A larger river channel means their is less friction, so the water flows faster:

• As the river erodes sideways, to the right and the left side, it forms large bends, and then the horseshoe like loops called meanders
• The formation of the meanders is due to both deposition and erosion and meanders gradually gradually migrate down 
• On the inside of the bend, where the river flow is slower, material deposited as there is more friction. The force of the water erodes and undercuts the river bank o the…