The name Perennial is derived from a Latin word ‘perennis’, which means lasting throughout the year. As they flow continuously throughout the year irrespective of seasons, they are also called permanent rivers. Mostly they originate from the mountain and the water is fed by melting of glaciers. These rivers are mostly found in North India due to the presence of the great mountain range Himalaya that is fully covered with snow. Whereas in south India there is no mountain with snow so the south Indian rivers are non-perennial rivers. These streams are of vital importance in agriculture because they provide water throughout the year. For e.g.,Ganga is the best example of a perennial river. These rivers get water by rain in rainy season, melting of ice in summer and by snow in the winter season. Other examples include the Indus and its five tributaries, they are Chenab, Jhelum, Beas, Ravi and Sutluj. In the same way, major river Ganga and its tributaries are Gandak, Yamuna, Gomti, Garghara, and Kosi. River Brahmaputra and its tributaries namely, Torsa, Tista, Manas, Jaldhaka, Subansiri, Dibang, Lohit etc.