Mekedatu Dam Dispute — Supreme Court, Cauvery, and Federalism

General Studies Paper 2 — Polity, Federalism, Inter-State Relations Source: Supreme Court of India, 2025–26

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1. What happened

The Supreme Court dismissed Tamil Nadu’s review petition against the proposed Mekedatu Balancing Reservoir by Karnataka. The Court had earlier called Tamil Nadu’s opposition “premature” and reiterated that until the project’s Detailed Project Report is officially approved, no legal challenge can be entertained.

• Tamil Nadu fears the dam will reduce the natural flow of Cauvery water reaching its farmers.
• Karnataka says it will only store surplus flood water — not affect Tamil Nadu’s share.
• The Court confirmed Karnataka is still legally bound to release Tamil Nadu’s allocated Cauvery water regardless of this project.

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2. About the Mekedatu project

Mekedatu — Location and Purpose

Karnataka: Mekedatu means “Goat’s Leap” in Kannada — a deep gorge where Cauvery meets its tributary Arkavathi in Ramanagara district. Tamil Nadu: Lower riparian state — depends on Cauvery for Samba crop agriculture and drinking water in delta districts.

Upper riparian state = Karnataka (river flows through here first). Lower riparian state = Tamil Nadu (receives water downstream).

• Drinking water: Supply approximately 4.75 TMC of water to Bengaluru city and surrounding areas.
• Power generation: Produce 400 MW of hydroelectric power.
• Current status: Karnataka is submitting a revised Detailed Project Report to central authorities — project not approved yet.

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3. Karnataka vs Tamil Nadu — the core argument

Karnataka’s argument

• Will only store surplus monsoon flood water — not divert Tamil Nadu’s share.
• Drinking water is a national priority — higher than irrigation.
• Bengaluru faces a severe water crisis.

Tamil Nadu’s argument

• Any dam on Cauvery will reduce natural downstream flow.
• Violates Cauvery Tribunal award and Supreme Court judgments.
• Distress sharing during low-rainfall years will worsen for farmers.

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4. The constitutional and legal framework

Article 262: Parliament can adjudicate inter-state river water disputes. State List, Entry 17: Water is a state subject. Union List, Entry 56: Parliament can regulate inter-state rivers in public interest. Inter-State River Water Disputes Act, 1956: Law under which river tribunals are created.

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5. Value box — key bodies and terms

Cauvery Water Management Authority

Apex body created after the Supreme Court’s 2018 Cauvery verdict to regulate Cauvery waters among Karnataka, Kerala, Tamil Nadu, and Puducherry.

Cauvery Water Regulation Committee

Technical body under the Cauvery Water Management Authority that monitors rainfall, water flow, and reservoir storage.

Detailed Project Report

Technical document required before approval of any major river project.

Riparian rights

Rights of states sharing a river. Upper riparian states can use water but cannot deprive downstream states of their due share.

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Prelims Practice Question

Consider the following statements regarding the Mekedatu project and India’s inter-state river water framework:

1. The Mekedatu project is located at the confluence of the Cauvery and Arkavathi rivers in Karnataka.
2. Under the Constitution, water is a Union subject.
3. The Cauvery Water Management Authority was created after the Supreme Court’s 2018 verdict.

(a) 1 and 2 only (b) 2 and 3 only (c) 1 and 3 only (d) 1, 2 and 3 Correct answer: (c) 1 and 3 only