A smaller stream joining with the main stream is known as tributary. A tributary generally carries water and silt to the main river. River Jamuna is an example of tributary of the river Ganga.
A Distributary is formed at the lower course of the river when the main channel of the river gets blocked with silt which forced river to open branches. The Bhagirathi-Hooghly is a distributary of the river Ganga. The main function of the distributary is to distribute water through newly opened channels. The three basic differences between tributaries and distributaries are given below:
Tributary
Tributaries can be found in three stages of the river – upper, middle and lower.
It is useful for irrigation and transportation all through.
It brings water and silt from its catchment area.
Tributaries are fast-flowing.
Distributary
It is only found in lower course of the river.
It only provides a network of transport in the lower course.
It deposits silt in its course.
Distributaries are slow-flowing.
