There are more than 400 rivers in India.[1] As per the classification of Food and Agriculture Organization, the Indian rivers are combined into 20 river units, which includes 14 major rivers systems and 99 smaller river basins grouped into six river units. The rivers of India can be classified into four groups - Himalayan, Deccan, Coastal, and Inland drainage.[2] [3]
Most of the rivers in India originate from the four major watersheds in India. The Himalayan watershed is the source of majority of the major river systems in India including the three major rivers - the Ganges, the Brahmaputra and the Indus.[3] [4] These three river systems are fed by more than 5000 glaciers.[5]
The Aravalli range in the north-west serves as the origin of few of the rivers. The Narmada and Tapti rivers originate from the Vindhya and Satpura ranges in Central India.[4] In the peninsular India, majority of the rivers originate from the Western Ghats and flow towards the Bay of Bengal, while only a few rivers flow from east to west from the Eastern Ghats to the Arabian sea. This is because of the difference in elevation of the Deccan plateau, which slopes gently from the west to the east.[6] The major peninsular rivers include the Godavari, the Krishna, the Mahanadi and the Kaveri.[3] [4]