Tributaries:-
1. The small river which joins a large river is called the tributary of the large river.
2. It increases the water level of main river.
3. Yamuna, Kosi, Gandak etc. are the tributaries of Ganga River.
Distributaries
1. In its lower course river water is divided into many channels forming distributaries
2. It reduces the water level of main river.
3. Bhagirathi- Hooghly is the distributary of Ganga river.

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