Hey, hope you are doing well!

A main river is basically that part of the river which starts from the origin and is not a distributary or branch of any other river.

A main river flows into a larger stream and then bifurcates into various number of distributaries. Distributaries are the branches of a main river.

Examples-

• Kollidam river is a distributary of the Kaveri River.
• Nara river is a distributary of Indus River.
• Akhtuba River is a distributary of the Volga river.

So the main rivers in the above mentioned examples are Kaveri river, Indus river and Volga river.

The distributaries are Kollidam river, Nara river and Akhtuba river.

The Kaveri river rises at Talakaveri on the Brahmagiri range in the Western Ghats, Kodagu district of the state of Karnataka, at an elevation of 1,341 m above mean sea level and flows for about 800 km before its outfall into the Bay of Bengal.

Indua River originates in theTibetan Plateauin the vicinity ofLake Manasarovar the river runs a course through the Ladakhregion of India, towardsGilgit-Baltistanand then flows in a southerly direction along the entire length ofPakistanto merge into the Arabian Sea near the port city ofKarachi and Sindh.

Volga river rises in the Valdai Hillsnorthwest of Moscow, the Volga discharges into theCaspian Sea.

So, in a main river's journey it bifurcates and creates many distributaries.

Hello Siddeq !

A main river is defined as a watercourse marked as such on a main river map, and can includd any structure or appliance for controlling or regulating the flow of water in, into or out of a main river.

All the best !