NCERT Chapter Summary: Drainage

The term drainage describes the river system of an area. Small streams flowing from different directions come together to form the main river, which ultimately drains into a large water body such as a lake or a sea or an ocean. The area drained by a single river system is called a drainage basin.

The drainage systems of India are mainly controlled by the broad relief features of the subcontinent. Accordingly, the Indian rivers are divided into two major groups: the Himalayan rivers and the Peninsular rivers.

The major Himalayan rivers are the Indus, the Ganga and the Brahmaputra. The river Indus rises in Tibet, near Lake Mansarowar. Flowing west, it enters India in the Ladakh district of Jammu and Kashmir. The headwaters of the Ganga, called the ‘Bhagirathi’ is fed by the Gangotri Glacier and joined by the Alaknanda at Devaprayag in Uttarakhand.

The Brahmaputra rises in Tibet east of Mansarowar lake very close to the sources of the Indus and the Satluj. It is slightly longer than the Indus, and most of its course lies outside India.

Most of the major rivers of the Peninsula, such as the Mahanadi, the Godavari, the Krishna and the Kaveri flow eastwards and drain into the Bay of Bengal. These rivers make deltas at their mouths. The Narmada and the Tapi are the only long rivers, which flow west and make esturies.