The Peninsular Rivers of India

Peninsular rivers are older than Himalayan rivers and behave differently. They rise in the Western Ghats or the central highlands, flow across hard, ancient rock, and reach the sea through broad, shallow valleys. Most are seasonal, depending mainly on monsoon rain rather than snowmelt, so their flow is high in the monsoon and low, or even dry, in summer. They also tend to be shorter and to have smaller basins than the great Himalayan rivers, but they are vital to the Deccan, where rainfall is lower and less reliable.

The east-flowing rivers are the largest group. The Godavari, at about 1,465 kilometres, is the longest peninsular river and is sometimes called the Dakshin Ganga, or Ganga of the South. It rises near Trimbak in Maharashtra and flows through Telangana and Andhra Pradesh to the Bay of Bengal. The Krishna, at about 1,400 kilometres, rises near Mahabaleshwar in Maharashtra and flows through Karnataka, Telangana and Andhra Pradesh. The Kaveri, at about 800 kilometres, rises in the Brahmagiri hills of Karnataka and flows through Tamil Nadu to the Bay of Bengal; its water has been the subject of a long-running dispute between Karnataka and Tamil Nadu, settled in outline by tribunal and Supreme Court proceedings.

The west-flowing rivers are fewer and shorter, because the Western Ghats stand close to the west coast. The Narmada, at about 1,312 kilometres in India, rises in the Amarkantak plateau and flows westwards through a rift valley to the Arabian Sea, as does the Tapi (Tapti) further south. Their westward flow is a clue to the plateau's geology: they follow fault lines rather than the general west-to-east slope. The Narmada valley is also the site of the Sardar Sarovar project and a long debate about large dams, displacement and environmental costs, which shaped India's debate on development itself.

For civil studies, peninsular rivers illustrate water scarcity and sharing. Because they are seasonal, dams, tanks and groundwater recharge matter more here than on the perennial Himalayan rivers. Because they cross states, their sharing is a federal issue, handled through tribunals under the Inter-State River Water Disputes Act, 1956, as well as through negotiation and court decisions. A reader who understands why peninsular rivers are seasonal, why they flow east, and why they are disputed understands much of India's water politics.