The row over the Mekedatu dam project, which has been a thorn in the relationship between Tamil Nadu and Karnataka, has resurfaced with the Tamil Nadu Assembly adopting a unanimous resolution against the Karnataka government’s proposal for constructing a drinking water-cum-balancing reservoir across the Cauvery river at Mekedatu.

The reason for the resolution was apparently the preparation on the part of the upper riparian State to go ahead with the submission of a revised Detailed Project Report (DPR) on the Mekedatu proposal in light of the Supreme Court dismissing Tamil Nadu’s petition to review a November 2025 decision; the court termed the State’s challenge to Karnataka’s proposed dam as “premature”. The project envisages impounding 67.16 thousand million cubic ft (TMC ft) through a ₹9,000-crore drinking water-cum-balancing reservoir at Mekedatu, about 100 km from Bengaluru. It would have a 400 MW (megawatt) hydro power component but no irrigation component.

In the Supreme Court’s 2018 judgment on the Cauvery dispute, Karnataka had been sanctioned an additional 4.75 TMC for Bengaluru’s drinking water requirements.

On the face of it, the Mekedatu project, which is being proposed to cater to Bengaluru’s requirements, should not even be a matter of concern to the lower riparian State. But what is complicating the issue is the trust deficit between the two riparian States, as a result of which Tamil Nadu views the proposal with suspicion for legitimate reasons. The lower riparian State’s basic point is that the Cauvery being deficit, no new project is permissible.

Karnataka Chief Minister D.K. Shivakumar and his colleagues have said that the new dam will benefit Tamil Nadu too as it will serve as a balancing reservoir to regulate the flood flows from the upstream Krishnaraja Sagar and Kabini to the Mettur dam downstream in the lower riparian State.

A tense negotiation

In the last 10-odd years, the Tamil Nadu Assembly has passed, on several occasions, motions against the project.

However, a new element to the contentious matter is the lower riparian State’s demand for a tribunal to examine the pros and cons of the project. Though the Tamil Nadu government sent a formal communication on March 4 to the Centre, this was kept under wraps till June 19, the day on which the House adopted the resolution.

The previous Dravida Munnetra Kazhagam government, which took the decision to seek a tribunal for the project, had, for inexplicable reasons, maintained silence and the present Tamilaga Vettri Kahagam government too followed suit till now.

However, the Leader of Opposition and former Deputy Chief Minister Udhayanidhi Stalin disclosed it last week in the House and requested Chief Minister C. Joseph Vijay to include it in the resolution. Mr Vijay immediately agreed to the request but former Chief Minister and the All India Anna Dravida Munnetra Kazhagam general secretary Edappadi K. Palaniswami pointed out that there was a procedural lapse with regard to the way the amendment was incorporated in the resolution.

When Tamil Nadu had pursued the concept of a tribunal in the past to resolve the basic dispute over the sharing of Cauvery river water, it had done so after attending 23 bilateral or tripartite or multi-stakeholder meetings involving the governments of Karnataka, Kerala, and the Union Territory of Puducherry, besides the Central government. However, in the last 15 years, not even one meeting took place between the two principal States on the Mekedatu issue. Under such circumstances, it is not known whether the Union government will take a sympathetic view of Tamil Nadu’s request, as the Inter-State River Water Disputes Act requires the Centre to accept the demand for a tribunal only when it is convinced that the dispute cannot be settled through negotiations.

Even if the idea is acceded to, there is no guarantee that Tamil Nadu will be able to succeed in its plan of scrapping the project.

To safeguard the interests of farmers and ensure that the drinking water requirements of Bengaluru be met, the two States can explore the possibility of building a dam in Rasimanal, which is in Tamil Nadu, for a similar capacity.

ramakrishnan.t@thehindu.co.in