Interlinking of rivers

Also called: National Perspective Plan, National River Linking Project, NRLP, ILR, National Perspective Plan for interlinking of rivers, NPP · Topic: Drainage System of India: Rivers, Basins and Patterns · NCERT: Class 11, Ch 3 "Drainage System"; Class 11, Ch 6 "Natural Hazards and Disasters: Causes, Consequences and Management"; Class 12, Ch 4 "Water Resources"

Meaning

Interlinking of rivers (ILR) is a national plan to join river basins that have "surplus" water to basins that lack water, using dams, canals and tunnels. The aim is for floodwater in one area to help a drought-hit area somewhere else. Its official blueprint is the National Perspective Plan (NPP), 1980, which lists 30 links: 14 Himalayan and 16 Peninsular.

It matters because India's water problem is mostly one of management, not of availability. In the same season, Assam and Bihar can flood while Bundelkhand and Marathwada stay dry. ILR is the government's biggest answer to this gap, and it is also one of its most debated projects.

Explanation

Why India needs it: water is uneven in time and in space

• Uneven in time:
• Most river flow comes in the 3–4 monsoon months.

• Much of this floodwater runs into the sea without being used.

• Uneven in space:

• Himalayan rivers such as the Ganga and Brahmaputra are perennial (they flow all year). They are fed by monsoon rain and by melting snow and glaciers.

• Many Peninsular rivers are non-perennial (they have little or no water in the dry season) because they are fed by rain alone. The Ken and Betwa, for example, have low summer flow.

• Result: some regions flood while others face drought. ILR tries to move water from the "surplus" basins to the "deficit" ones.

How it works: inter-basin transfer

• Inter-basin transfer means moving water from one river basin to another through dams, tunnels and canals.
• Process:
• A dam stores the extra water in the "surplus" basin.
• Canals or tunnels carry that water across the watershed (the high ground between two basins).

• The water then goes to the "deficit" basin for irrigation, drinking water, industry and hydropower.

• What the land allows: water moves easily downhill or along the same level. It is very hard to lift water from the plains onto a plateau.

• K.L. Rao's Ganga–Kaveri link canal (1972, about 2,640 km) was dropped for this reason. Water would have had to be lifted about 450 m onto the Deccan Plateau, which needs huge amounts of energy at a very high cost.

The parts of the National Perspective Plan

• Himalayan component: 14 links.
• Water from the Ganga, the Brahmaputra and their tributaries would be stored.

• It would then be sent west and south.

• Peninsular component: 16 links.

• These join the Mahanadi, Godavari, Krishna, Pennar and Kaveri, plus some west-flowing rivers.

• National Water Development Agency (NWDA): set up in 1982 to study the links.

• Progress on studies: NWDA has finished Pre-Feasibility Reports for all 30 links, Feasibility Reports for 26 and Detailed Project Reports (DPRs) for 13 [7].
• Priority links: Ken–Betwa, Modified Parbati–Kalisindh–Chambal and Godavari–Cauvery (which has three sub-links) [7].

The debate: arguments against ILR

• Do the surpluses really exist? "Surplus" basins may be short of water themselves in dry years. Odisha and Andhra Pradesh question the figures.
• Ecological flow: this is the minimum amount of water a river must keep to support fish, wetlands and people downstream. Taking water out of a river can push its flow below this level.
• Delta starvation:
• Dams trap silt.
• Deltas such as those of the Godavari, Krishna and Mahanadi then get less sediment.

• So these deltas sink, and the sea eats into them.

• Submergence and displacement: reservoirs flood forests and villages. Under Ken–Betwa, part of Panna Tiger Reserve will go under water.

• Seismicity: large dams and canals in the Himalaya would cross zones that get many earthquakes.
• Cost: the whole programme would cost lakhs of crores. Ken–Betwa alone costs about ₹44,605 crore.
• State consent: water is a state subject, so the states that share a basin must agree before a link can go ahead.

Where it occurs

National programme

• The National Perspective Plan (1980) covers the whole country. NWDA (set up in 1982) studies the links. The Ministry of Jal Shakti signs the agreements with the states.

Ken–Betwa Link Project (Madhya Pradesh–Uttar Pradesh): the first link under way

• The Ken and the Betwa are both right-bank tributaries of the Yamuna. They flow north across the drought-prone Bundelkhand region.
• "Surplus" Ken water is moved to the Betwa basin.
• Union Cabinet approval: 8 December 2021. Total cost: about ₹44,605 crore. Central support: ₹39,317 crore, made up of a ₹36,290 crore grant and a ₹3,027 crore loan [2].
• Foundation stone: laid by the Prime Minister at Khajuraho, Madhya Pradesh, on 25 December 2024 [4].
• Daudhan dam: 96.7 m high, on the Ken, in Panna and Chhatarpur districts, about 40 km from Khajuraho [3].
• Planned benefits: irrigation of 10.62 lakh ha a year, drinking water for about 62 lakh people, 103 MW of hydropower and 27 MW of solar power [3].
• Status: the dam is being built, but canal work has not yet started [3][8].

Modified Parbati–Kalisindh–Chambal–ERCP link (Madhya Pradesh–Rajasthan)

• The Parbati and Kalisindh are tributaries of the Chambal. They flow north from the Malwa Plateau into Rajasthan.
• Steps so far:
• February 2004: NWDA sent the Feasibility Report to the states.
• 2019: Rajasthan proposed its own Eastern Rajasthan Canal Project (ERCP). The two plans were later merged [5].
• 28 January 2024: an MoU (Memorandum of Understanding, a written agreement to work together) was signed by Madhya Pradesh, Rajasthan and the Ministry of Jal Shakti [5].

• 5 December 2024: a Memorandum of Agreement for carrying out the project was signed [6].

• Benefits: water for 13 districts of eastern Rajasthan and for the Malwa and Chambal regions of Madhya Pradesh. Irrigation of at least 2.8 lakh ha in each state, or at least 5.6 lakh ha in total [5].

Godavari–Cauvery link (Telangana/Andhra Pradesh to Tamil Nadu)

• Godavari "surplus" water would be moved south through the Krishna and Pennar basins to the Cauvery. The draft DPR went to the states in March 2019 [7].

• Three sub-links [7]: 1. Godavari (Inchampalli/Janampet) → Krishna (Nagarjunasagar) 2. Krishna (Nagarjunasagar) → Pennar (Somasila) 3. Pennar (Somasila) → Cauvery (Grand Anicut)

• Interim plan: move about 4,189 MCM (million cubic metres) from the Godavari. This would be combined with the Bedti–Varda link, which would add water to the Krishna basin [7].

Older inter-basin transfers that are already working

• Periyar diversion scheme: water from the Periyar in Kerala goes east through the Western Ghats to the Vaigai basin in Tamil Nadu.
• Indira Gandhi Canal: Satluj–Beas water goes from the Harike barrage in Punjab to the Thar Desert in Rajasthan.
• Kurnool–Cuddapah canal: water goes from the Krishna basin (Tungabhadra) to the Pennar basin in Andhra Pradesh. It was built in the 1860s.
• Beas–Satluj link: Beas water from Pandoh in Himachal Pradesh goes to the Satluj, for the Bhakra dam.

Don't confuse with

• Ganga–Kaveri link canal vs Godavari–Cauvery link: the Ganga–Kaveri canal was K.L. Rao's 1972 plan, and it was dropped because lifting water about 450 m onto the plateau would cost too much. The Godavari–Cauvery link is a current NPP priority link, with three sub-links running through Nagarjunasagar and Somasila [7].
• Ken–Betwa vs PKC–ERCP: Ken and Betwa are direct right-bank tributaries of the Yamuna in Bundelkhand (MP–UP). Parbati and Kalisindh are tributaries of the Chambal in Malwa and eastern Rajasthan (MP–Rajasthan).
• NPP links vs older inter-basin transfers: the 30 NPP links come from the 1980 national plan. The Periyar, Kurnool–Cuddapah (1860s), Beas–Satluj and Indira Gandhi Canal schemes are older regional transfers that are already running.
• ILR vs Satluj–Yamuna Link (SYL) canal: ILR moves "surplus" water to deficit basins. The SYL is a 214 km canal to carry Haryana's share of Ravi–Beas water. It is stuck in an inter-state sharing dispute: Haryana has finished its part, but Punjab has stopped work on its part.

Prelims Hooks

• NPP 1980: 30 links, with 14 Himalayan and 16 Peninsular. NWDA was set up in 1982. Pre-Feasibility Reports are done for all 30 links, Feasibility Reports for 26 and DPRs for 13 [7].
• Ken–Betwa: Cabinet approval on 8 Dec 2021 [2]. Foundation stone laid on 25 Dec 2024 at Khajuraho [4]. The Daudhan dam (96.7 m) is in Panna–Chhatarpur, MP, and will flood part of Panna Tiger Reserve [3].
• PKC–ERCP: Parbati and Kalisindh → Chambal. MoU signed on 28 Jan 2024 and MoA on 5 Dec 2024, between MP and Rajasthan [5][6].
• Godavari–Cauvery sub-links, from north to south: Inchampalli/Janampet → Nagarjunasagar → Somasila → Grand Anicut [7].
• Trap: the Ganga–Kaveri link (K.L. Rao, 1972, about 2,640 km) was dropped because of the energy cost of lifting water about 450 m, not because of a court ruling or a dispute between states.
• Trap: the Ken and Betwa are tributaries of the Yamuna, not of the Ganga directly, and both flow north across Bundelkhand.

Mains Points

• Case for ILR (GS-III, resources and disasters):
• The same monsoon brings floods to Assam and Bihar and drought to Bundelkhand and interior Karnataka, so moving water could ease both problems.

• Ken–Betwa (10.62 lakh ha of irrigation, water for 62 lakh people) and PKC–ERCP (at least 5.6 lakh ha) offer relief to Bundelkhand and eastern Rajasthan [3][5].

• Case against ILR (GS-III, environment):

• "Surplus" figures are doubtful, and states such as Odisha and Andhra Pradesh dispute them.
• Taking out water can push rivers below their ecological flow, and dams starve the Godavari, Krishna and Mahanadi deltas of silt.

• Other costs include the loss of part of Panna Tiger Reserve, seismic risk in the Himalaya and a price tag of lakhs of crores.

• Way forward (GS-I/III):

• Go basin by basin, with the consent of the states (water is a state subject) and proper environmental checks.
• Learn from past schemes. Regional transfers such as Periyar and the Indira Gandhi Canal work, but the Ganga–Kaveri plan shows the limit of lifting water from the plains to the plateau.
• Use ILR alongside storage, watershed management and pollution control, because India's crisis is mostly one of management.

Related concepts

• Usability of river water
• Thalweg
• Ganga-Kaveri link canal
• Parbati-Kalisindh-Chambal-ERCP link
• Godavari-Cauvery link
• Inter-State River Water Disputes Act 1956
• Krishna water dispute
• Satluj-Yamuna Link canal

Read more

• Using river water: usability, disputes and interlinking