Drainage System of the Peninsular Rivers: East-Flowing and West-Flowing Rivers

At a Glance

• Character Seasonal, rain-fed, mature
• Godavari About 1,465 km; Dakshin Ganga
• Krishna About 1,400 km; Bhima and Tungabhadra
• Kaveri About 800 km; Talakaveri
• Mahanadi About 851 km; Hirakud
• Exam link UPSC Prelims, Geography: Physical Geography of India

Where Does It Fit?

This topic follows the Himalayan rivers and covers the older, seasonal rivers of the Peninsula. They are divided by the Western Ghats watershed into a larger east-flowing group, which forms deltas, and a smaller west-flowing group, which forms estuaries. Previous topic: Drainage System of the Himalayan Rivers: Indus, Ganga, Brahmaputra River Networks. Next topic: Factors Affecting India’s Climate.

How Do Peninsular Rivers Differ From Himalayan Rivers?

Each of the large rivers builds a river delta at its mouth. The Western Ghats form the main water divide, and the rivers flow east, as in Geological Regions of India: Deccan Plateau, The Himalayas, Other Peninsular Mountain Ranges, Indo-Gangetic-Brahmaputra Plain. The origin of the pattern is explained by two ideas. The first is that the Sahyadri–Aravalli axis was once the central divide of a larger land mass, whose western half sank into the Arabian Sea during the Tertiary; the rift valleys of the Narmada and Tapti are the result. The second is that the faulting caused by the bending of the northern Peninsula at the time of the Himalayan upheaval tilted the block eastward. The first is considered more likely, as the straight west coast, the steep scarp of the Ghats and the absence of deltas on the west support it.

What Are the Main East-Flowing Rivers?

What Are the Disputes and River-Linking Plans?

• Cauvery dispute: a Supreme Court judgment of 2018 allocated about 404 TMC of water to Tamil Nadu and about 285 TMC to Karnataka, with smaller shares for Keralam and Puducherry, and the Cauvery Water Management Authority supervises the release. Karnataka’s Mekedatu dam proposal remains contested.
• Krishna and Godavari: the Krishna Water Disputes Tribunal and the Godavari Water Disputes Tribunal have made awards, but the sharing among the states formed after the division of Andhra Pradesh is still in dispute. The Polavaram project is under construction.
• Mahanadi: Odisha and Chhattisgarh dispute the use of water, and a tribunal was set up to examine it.
• River linking: the interlinking of rivers programme, based on the National Perspective Plan of 1980 proposed a Himalayan and a Peninsular component. The Ken–Betwa link, whose foundation stone was laid in December 2024, is the first project. The Godavari–Cauvery link is also being studied to carry water from surplus basins to deficit ones, as in Drainage System of the Himalayan Rivers: Indus, Ganga, Brahmaputra River Networks.

As an analytical point, the Peninsular rivers are the most heavily regulated in the country; the Cauvery, Krishna and Godavari are almost fully used, so the struggles over their water are as much about the allocation among states as about shortage, and the effect of climate change on the monsoon will make rules for years of deficit as important as the rules for normal years.

What Are the Narmada and the Tapti?

The two rivers flow almost parallel but in the opposite direction to most peninsular rivers, since they occupy rift valleys formed by faults. The Narmada is the largest of the west-flowing rivers of the Peninsula. Both form estuaries, as the hard rocks and straight course prevent the formation of distributaries and a delta, and the tides remove their sediments. The valleys have fertile alluvium and teak forests, and the Tapti is known as the twin of the Narmada.

The Sardar Sarovar Dam on the Narmada in Gujarat, completed in 2017 and about 139 m high, serves irrigation and hydropower in Gujarat, Madhya Pradesh, Maharashtra and Rajasthan, and is near the Statue of Unity. It was the subject of the Narmada Bachao Andolan, a movement over the displacement of people and the rehabilitation of those affected, which has made the Narmada dams a standard case study of development and displacement.

What Are the Other West-Flowing Rivers?

• Sabarmati: formed by the Sabar and Hathmati streams, rises in the Aravalli hills near Udaipur in Rajasthan, about 371 km long, falls into the Gulf of Khambhat; Ahmedabad is on its banks, and the Sabarmati Riverfront has been developed there; the Dharoi dam is on it.
• Mahi: rises in the Vindhya hills of Madhya Pradesh, about 583 km long, flows through Rajasthan and Gujarat, and crosses the Tropic of Cancer twice. The Mahi Bajaj Sagar and Kadana dams are on it.
• Luni: the Salt River, rising from the western slopes of the Aravalli near Ajmer, about 511 km, the only significant river of western Rajasthan, seasonal, and brackish below Balotra; it disappears in the Rann of Kachchh without reaching the sea.
• Ghaggar: a seasonal inland river from the Shiwaliks lost in the sands of Rajasthan, linked by some scholars to the ancient Saraswati.

What Are the Rivers of the Western Ghats?

The Western Ghats rivers are hundreds of small streams that fall from the Western Ghats directly into the Arabian Sea over a short course of less than 100 km on average. They are fast and steep, with high rainfall catchments, and carry only a small share of the country’s river water. The main ones are the Mandovi and Zuari in Goa, the Sharavati, which makes the Jog Falls, one of the highest waterfalls in India at about 250 m, the Netravati near Mangalore, and, in Keralam, the Periyar, the longest river in Keralam, the Bharathapuzha and the Pamba. The Dudhsagar Falls, on the Mandovi on the Goa–Karnataka border, and the Athirappilly Falls on the Chalakudy are other well-known falls. The rivers feed the Keralam backwaters and form estuaries and lagoons, as in Coastal Plains, Coral Reefs and Islands of India (Andaman and Nicobar Islands, Lakshadweep).

These rivers are the main source of hydropower for Keralam and Karnataka, and their short courses mean that floods rise and fall quickly. The Keralam floods of 2018 and the Wayanad landslides of 2024 showed how the same steep slopes that give power also give hazards. India has proposals to divert the surplus water of the west-flowing rivers, such as the Par–Tapi–Narmada and Damanganga–Pinjal links, to dry regions, as in Drainage System of the Himalayan Rivers: Indus, Ganga, Brahmaputra River Networks. As an analytical point, the west coast rivers carry little of the nation’s water, but since they pass through the densest part of the rainfall, they define the water and hazard profile of Keralam, Karnataka, Goa and Konkan more than any inland river does.

Why Does the Bay of Bengal Receive So Much More Water?

• Himalayan rivers: the perennial Ganga and Brahmaputra, which carry the largest volumes, flow east.
• Rainfall: the eastern basins get rain from both the southwest and northeast monsoons and from cyclones, while the Arabian Sea basins, including Rajasthan, Haryana and Punjab in the Indus system, are drier, as in Monsoon Mechanism: Traditional and Contemporary Theories (Air Mass Theory, Jet Stream Theory).
• Slope: the Peninsula slopes eastward, so its large rivers flow to the Bay of Bengal, while the west-flowing rivers are short and steep streams from the Western Ghats, apart from the Narmada and the Tapti.
• Result: over 90 per cent of India’s river water drains to the Bay of Bengal, even though it covers a smaller share of the area, and this has a bearing on the planning of river-linking schemes.

Why Is This Topic Important?

• Facts Sources and lengths asked
• Disputes Cauvery and Krishna
• Policy River-linking

What Came Next?

The next topic describes the factors that affect the climate of India. Next topic: Factors Affecting India’s Climate.

Key People and Terms

• Dakshin Ganga Godavari, the Ganga of the south
• Concordant drainage Drainage following the slope or structure
• Lobate delta Rounded delta with many distributaries
• Grand Anicut Ancient Cauvery weir
• TMC Thousand million cubic feet
• Link canal Channel moving water between basins

Exam Corner

Mains Angle

Questions compare the Peninsular rivers and ask about disputes. These points add depth.

• Nature Seasonal and mature
• Use Intensive regulation
• Conflict Interstate sharing