Introduction
India experiences acute spatial and temporal rainfall disparity, leading to recurring floods in the Ganga-Brahmaputra basin alongside chronic water distress in peninsular regions. To resolve this imbalance, the National Perspective Plan (NPP) formulated by the Ministry of Water Resources envisions 30 river links (16 Peninsular and 14 Himalayan) to transfer surplus water to deficit basins.
Addressing Regional Water Imbalances
Inter-basin water transfers aim to redistribute surface water from flood-prone basins to water-stressed regions, unlocking significant socio-economic benefits:
- Irrigation and Food Security: The complete interlinking program targets bringing approximately 35 million hectares under irrigation and generating 34,000 MW of hydroelectric power. For example, the Ken-Betwa Link Project (KBLP) is designed to irrigate 11.88 lakh hectares in the drought-prone Bundelkhand region.
- Drinking Water Augmentation: Channeling surplus flows fulfills critical domestic water needs for fast-growing urban centers and parched rural settlements, including providing drinking water to 62 lakh people under the Ken-Betwa project.
- Climate Buffering: Moderates high flood peaks in northern Himalayan rivers by diverting excess runoff, while simultaneously drought-proofing rainfed peninsular agricultural belts.
Ecological Challenges
Large-scale diversions and impoundments severely affect natural river dynamics and biodiversity:
- Habitat Submergence and Deforestation: Major reservoirs submerge pristine forests and critical wildlife corridors. For instance, the Daudhan dam under the Ken-Betwa link will submerge around 5,400 hectares of core and buffer forest inside the Panna Tiger Reserve.
- Eco-hydrological Disruption: Diverting flows diminishes minimum environmental flows (e-flows) necessary for riverine ecosystems, disrupts natural sediment transport to delta regions, and triggers coastal salinity ingress in estuaries.
- Methane Emissions and Microclimate Alterations: Large tropical reservoirs contribute to greenhouse gas emissions via submerged organic matter decomposition and can disrupt local microclimates.
Federal and Governance Challenges
Water governance in India is embedded in complex intergovernmental relations, leading to substantial political frictions:
- Constitutional Division of Powers: Friction arises between the legislative jurisdiction of states over water supplies, irrigation, and drainage under Entry 17 of the State List, and the Union's power over interstate rivers under Entry 56 of the Union List.
- Contested 'Surplus' Calculations: Riparian states frequently dispute Central hydrological yield assessments, fearing future water deficits within their own borders. Odisha, for instance, has opposed the Mahanadi-Godavari link over surplus claims, while Kerala rejected the Pamba-Achankovil-Vaigai project.
- Interstate Disputes and Displacement Politics: Upper and lower riparian states often clash over water-sharing formulas, while local resistance to displacement and rehabilitation adds socio-political friction across state borders.
Conclusion
While river interlinking offers engineering solutions to hydrological disparities, a purely supply-side approach creates irreversible ecological footprints and interstate conflicts. Following the recommendations of the Mihir Shah Committee, India must prioritize demand-side water management, micro-irrigation, and decentralized watershed restoration, while institutionalizing statutory River Basin Organizations for collaborative water federalism.