Cauvery Basin to Face Water Decline: Study Warns of Dry Spell by 2050
Context:
A study by IIT Gandhinagar published in Earth’s Future warns that the Cauvery River basin may witness a 3.5% decline in water availability between 2026 and 2050, even as most Indian rivers are expected to see increased flows due to climate change.
About Cauvery Basin:
The Cauvery basin is one of the most important river basins in southern India, originating at Talakaveri in the Western Ghats and flowing through Karnataka, Tamil Nadu, and parts of Kerala before draining into the Bay of Bengal.
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- Basin area: ~81,155 sq km
- Major tributaries: Hemavati, Kabini, Bhavani, Amaravati
- Key dams: Krishnarajasagar Dam and Mettur Dam
- Supports irrigation, drinking water, and hydropower
- Forms the fertile Cauvery delta, known as the “rice bowl” of Tamil Nadu
- Basin area: ~81,155 sq km
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Key Findings of the Study:
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- The study notes a historical decline of 28% in streamflow (1951–2012) and projects further reduction despite rising rainfall trends nationally.
- Using constrained climate models under CMIP6, researchers found that while rivers like the Ganga River may experience increased flows, the Cauvery basin will likely face water shortages in the near and mid-term.
- The study notes a historical decline of 28% in streamflow (1951–2012) and projects further reduction despite rising rainfall trends nationally.
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Implications for India:
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- The findings have serious implications for water security and inter-state relations. The Cauvery river has a long history of disputes between Karnataka and Tamil Nadu, leading to the establishment of the Cauvery Water Disputes Tribunal and the Supreme Court of India verdict in 2018, which allocated water shares. Declining water availability could intensify such conflicts, especially during drought years.
- Further, the basin supports agriculture, drinking water supply, and livelihoods in southern India. Reduced flows may impact crop productivity, urban water supply (e.g., Bengaluru), and ecological balance. The study also revives discussions on river interlinking projects, such as the proposed Godavari-Cauvery Link Project, though such solutions remain debated due to ecological and economic concerns.
- The findings have serious implications for water security and inter-state relations. The Cauvery river has a long history of disputes between Karnataka and Tamil Nadu, leading to the establishment of the Cauvery Water Disputes Tribunal and the Supreme Court of India verdict in 2018, which allocated water shares. Declining water availability could intensify such conflicts, especially during drought years.
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Challenges Highlighted:
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- Regional disparity in climate impacts
- Uncertainty in rainfall projections
- Increasing demand for limited water resources
- Existing interstate disputes and governance issues
- Regional disparity in climate impacts
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Way Forward:
India must adopt a multi-pronged strategy to address emerging water stress in the Cauvery basin. This includes improving water-use efficiency in agriculture, promoting rainwater harvesting, strengthening basin-level water governance, and enhancing climate-resilient infrastructure. Additionally, scientific advancements in climate modelling and data-driven policymaking are crucial for better planning.
Conclusion:
The projected decline in the Cauvery basin’s water availability underscores the uneven impacts of climate change across regions. It highlights the urgent need for cooperative federalism, sustainable water management, and climate adaptation strategies to ensure long-term water security and prevent future conflicts.
