River divided into many channels in lower course why
Answers
Answer:
Explanation:
The last part of a river near its mouth is called the lower course. In this part the slope of the river bed is not very steep. The current is also very slow. Deposition is the main activity of a river at this stage. The silt and other materials carried by the river are deposited. The river channel is blocked very often and new branch channels are dug out.
In this way branching takes place at the mouth of a river. These branch channels are known as distributaries and the river is said to be Braided. As the river meets the sea the current is almost halted.
Braided River
The silt carried by the river water is, therefore, deposited at the mouth. In the course of time, the silt thus deposited forms a triangular island at the mouth of the river. This is known as delta. When the tidal waves and sea currents constantly wash the river mouth a delta cannot be formed. Such a free mouth of a river is called an estuary.
Delta
Majuli, the river island and Sundarban (1,25,00 sq km) the delta of the Brahmaputra and the Ganges are world famous. The deltas of the Nile, Mississippi, Volga, Po and Yangstze kiang are some of the world famous depositional features at the mouth of the river.