India is country of rivers. Here, more than 400 big and small rivers are found, which can be divided into 23 large and 200 small river basins. Differences in Drainage Pattern and water levels are found in these (fig below) two types of river system which is shown in the below figure:
In India, water mainly drains in two directions of the main water divide line. 90% of land water drains into Bay of Bengal and the rest drains into Arabian Sea.
Summary on Indian Drainage System
1. The Indian Drainage System is divided into 3 categories: (1) Major River Basin with catchment area up to 20000 sq. km. and above, accounts for 83% of the total run off and are 13 in number in India. (2) Medium River Basin with catchment area of 2000-20000 sq. km. and above accounts of 8% of the total run off all the rivers and are 45 in India. (3) Minor River Basin with catchment area up to 2000 sq. km. It accounts for 9% of the total run off among all the rivers with 55 basins in India.
2. On the basis of physiographic origin the Indian drainage may be distinguished as the Himalayan drainage and the peninsular drainage. Himalayan drainage system mainly comprises the basin areas of the Indus, the Ganga and the Brahmaputra. These are mostly perennial and youth having gorges, V-shaped valley and depositional features like Deltas.
3. Many of the rivers are older than the Himalayas and cut across it. Whereas Peninsular Rivers is much older and includes numerous rivers. Rivers are matured with almost graded Profiles and mostly superimposed in nature i.e., follow the gradient or fault valley. These are devoid of meanders and have fixed course unlike Himalayan drainage.
4. River Indus flows through Ladakh and Zaskar Range. Gilgit is a right bank tributary of Indus.
5. Ganga River enters into plain at Haridwar. The number of tributaries of the River Ganga is more in Avadh Plain as compared to that in Rohilkhand Plain. Bhagirathi and Alaknanda meet at Devprayag and after that it takes the name of river Ganga.
6. Brahmaputra or Tsangpo flows through Tibet, India and Bangladesh and forms the largest delta of the world along with Ganga.
7. Important tributaries are Subansiri, Kameng, Dhansiri, Dihang, Lohit, Tista, Manas, etc. River Brahmaputra is called as Sikiang in Arunachal Pradesh and Jamuna in Bangladesh.
9. Mahanadi originates from Sihawa North foot hills of Dandakarnaya. Godavari originates from Trimbak Plateau of North Sahyadri near Nasik and Godavari makes boundary between Maharashtra and Andhra Pradesh.
10. Krishna originates North of Mahabaleshwar in the Western Ghat and along with Godavari it forms the 2nd largest delta in India. Koleru Lake lies in this delta.
11. Cauvery rises in Brahmagiri Range in Western Ghat. This is the only Perennial River in Peninsular India and creates contention among Kerala, Tamil Nadu, and Karnataka. cauvery forms a quadrilateral delta at its mouth.
12. Among the West flowing rivers Tapi and Narmada are flowing through rift valleys. Tapi rises near Multai in Betul Plateau and flows between Satpura and Ajanta-Satamala hills. Narmada flows between Vindhya and Satpura range. Rivers Luni, Ghaggar, Rupnarain, Medha, etc have inland drainage.