Ch 3Drainage System — Class 11 Geography, concept-first.

Water that flows through rivers, nalas and channels during the rainy season is not random — it is excess water being drained away.

The Indian drainage system is not a random scatter of rivers — it is the product of two forces working together over geological time.

The Himalayan drainage system is the product of a long geological history, shaped by the same forces that raised the mountains themselves.

The Himalayan drainage system is dominated by three great river systems—the Indus, the Ganga, and the Brahmaputra—each fed by a combination of glacial melt and monsoon rainfall.

The Indus, also called the Sindhu, is the westernmost of the Himalayan rivers in India. It is one of the largest river basins in the world, draining an area of 11,65,000 square kilometres, of which 32…

The Ganga is the most important river of India, both because of the size of its basin and its cultural significance.

The Brahmaputra is one of the largest rivers in the world, and its story is one of changing names, national borders, and enormous sediment loads.

Geologists do not all agree on how the Himalayan rivers evolved, but a widely accepted view holds that a single mighty river once ran the entire length of the Himalaya.

The Peninsular drainage system is the older of India’s two great drainage systems, and its age shows in the landscape.

The story of how Peninsular India’s rivers came to look the way they do is a story of three great geological upheavals.

The Peninsular drainage is not one river but a dense network of systems, each with its own source, course and character.

The central question this section raises is deceptively simple: India's rivers carry enormous volumes of water every year, yet the country faces both floods and droughts, often at the same time in dif…