Write an essay on the drainage system of India.

The term drainage is technically used for the river system of an area. India's drainage system is grouped in (i) The Himalayan rivers and (ii) The Peninsular rivers. Apart from this, there are inland drainage systems also.

The Himalayan rivers are the Indus, the Ganges and the Brahmaputra. The Indus water drains only 17,844 sq. km area in India because it flows outside the border of India since its rise from the Kailash range of Greater Himalayas. Its tributaries are the Zaskar, Shyok, Jhelum, Chenab, Ravi, Beas and Satluj. Indus is one of the largest river basins in the world, but its course in India is only 709 km.

The Ganges rises from Gangotri glacier and at the beginning, it is called Bhagirathi. Alaknanda meets it at Devprayag in Garhwal region and then it is named as Ganga. The Ganga with its tributaries viz. Yamuna, Ghaghra, Gandak, Kosi, Son, Chambal and Betwa drains 9,51,600 sq. km area and falls into the Bay of Bengal.

Brahmaputra rises from the Kailash range of Greater Himalayas near Mansarover. It flows eastwards parallel to the Himalayas to its south. It enters into India west of Sadiya town in Arunachal Pradesh. Its tributaries are Raja Tsangpo, Lhotse, Subansiri, Tista, Torsa and Dihang. It is long as the Indus and drains 5,80,000 sq. km area in India.

All these three major rivers fall into the Bay of Bengal.

Among Peninsular rivers, there are the Narmada, the Tapi, the Mahanadi, the Godavari, the Krishna and the Kaveri known as major rivers. The length of the Narmada and the Tapi are 1300 and 792 km respectively. The area drained by them is 93,080 and 792 sq. km respectively. These fall into the Arabian sea. Mahanadi rises in Chhattisgarh with its length 885 km and area drained is 1,92,000 sq. km Godavari rises in Nasik (Maharashtra). Its length is 1400 km and area drained by it is 2,60,000 sq. km. Kaveri rises from Brahmagiri hills. It drains 72,000 sq. km area and its length is 765 km. All these fall into the Bay of Bengal.

According to the slope of land, underlying rock structure and climatic conditions of the area, the rivers form dendritic (tree-like shapes), trellis, rectangular, radial and centifugal patterns. Ghaghar river of Haryana forms the centrifugal pattern of inland drainage.

The Himalayan rivers are perennial but the peninsular rivers are seasonal at the most. Owing to different rock structures, these form estuaries, gorges, water divide, rift valleys, basins, delta, doab etc. land-forms. Ganga-Brahmaputra delta or the Sunderban delta is the largest delta in the world.

Lakes are grouped into two i.e. (i) Natural lakes, (ii) Man-made lakes (or dams). Some natural lakes are Wulur, Dal, Nainital, Bhimtal, Loktak, Barapani, Chilka, Sambhar, Vembanad, Pulicat. Man-made lakes are : Govindsagar (Bhakra), Ranapratap Sagar, Nizamsagar, Nagarjunsagar, Gandhi Sagar and Hirakud. Some lakes are formed owing to the action of glaciers and ice sheets while some other are formed by wind, river action and human activities.