TN Seeks SC Order for 17.604 TMC Cauvery Water Backlog from Karnataka

Tamil Nadu has approached the Supreme Court seeking a direction to Karnataka to release 17.604 thousand million cubic feet of Cauvery water, described as the accumulated backlog as of August 27 calculated on a pro-rata basis. In a supplementary affidavit filed on August 30, the state also asked the court to ensure that Karnataka releases water at the rate of 9,000 cusecs from August 26 to September 8, in line with a recent decision of the Cauvery Water Management Authority.

The matter is listed before a Bench headed by Justice Vikram Nath. Tamil Nadu has argued that farmers in the Cauvery delta are severely affected because they are not receiving their due share of water. The state has further contended that the Cauvery Water Regulation Committee and the Cauvery Water Management Authority failed to take the accumulated shortfall into account while fixing the latest release schedule.

Background of the Current Dispute

The Cauvery water-sharing arrangement is governed by the final award of the Cauvery Water Disputes Tribunal as modified by the Supreme Court in 2018. Under the modified award, Karnataka is required to ensure specified quantities of water at the inter-state border point of Biligundulu according to a monthly schedule. In years of distress, when inflows fall short of normal levels, the principle of pro-rata or distress sharing is applied so that both upper and lower riparian states share the available water proportionately.

This monsoon season has been marked by below-normal rainfall in key catchment areas. Karnataka’s major reservoirs in the Cauvery basin have operated under constrained storage for much of the period. Tamil Nadu has repeatedly maintained that even after adjusting for the overall deficit, it has not received the proportionate quantum due to it. The state has tracked the shortfall at Biligundulu and updated the cumulative backlog figure in successive affidavits before the court.

Earlier in the season, the Cauvery Water Regulation Committee directed Karnataka to release 3,500 cusecs for a 15-day period. Subsequent meetings revised the daily quantum upward as conditions evolved. In late August the Committee fixed a release of 9,000 cusecs to be realised at Biligundulu from August 25 until September 8. Tamil Nadu’s grievance is that this direction addressed only the prospective flow and left the substantial accumulated backlog unaddressed.

Tamil Nadu’s Arguments Before the Court

In its latest affidavit, Tamil Nadu has placed the backlog at 17.604 tmcft as of August 27. The state has submitted that the Cauvery Water Regulation Committee, while setting the 9,000-cusec schedule, did not factor in the shortfall that had already built up. An earlier figure of 17.415 tmcft as of August 23 was cited in submissions, indicating that the deficit continued to be monitored closely.

Tamil Nadu has emphasised the dependence of the Cauvery delta on releases that ultimately reach the Mettur reservoir. A large irrigated area and the livelihoods of farmers and agricultural labourers are linked to the timely availability of water for the ongoing cultivation season. The state has argued that failure to clear the backlog compounds the distress already caused by deficient monsoon flows.

The affidavit was settled by senior counsel and presented as a supplementary filing to keep the court updated on the evolving situation after the previous hearing. At that earlier hearing on August 24, the Supreme Court had advised Tamil Nadu to raise its concerns about proportionate quantity before the Cauvery Water Regulation Committee and the Cauvery Water Management Authority in their scheduled meetings. The state has now returned to the court, contending that those bodies did not adequately address the backlog issue.

Role of the Regulatory Bodies

The Cauvery Water Management Authority and the Cauvery Water Regulation Committee form the institutional mechanism for implementing the Tribunal award as modified by the Supreme Court. The Regulation Committee reviews hydrological data, storage levels, inflows and realised flows at Biligundulu and issues time-bound release directions. The Management Authority oversees and can confirm or modify those directions.

In the present season the Committee has held multiple meetings to adjust release rates in response to changing reservoir positions and rainfall. Karnataka has at various points informed the Committee of deficit inflows relative to long-term averages and of the need to protect drinking-water and other essential requirements within the state. Tamil Nadu has consistently pressed for both current releases and clearance of accumulated shortfalls calculated on a pro-rata basis.

The difference in approach lies in whether the regulatory bodies should treat each fortnightly or monthly direction as a stand-alone obligation or whether they must also ensure that earlier shortfalls are made good so that the overall seasonal entitlement is not eroded. Tamil Nadu’s latest filing asserts that the latter course is necessary if the principle of distress sharing is to have practical meaning for the lower riparian state.

Implications for Farmers and Water Management

The Cauvery delta is one of the most intensively cultivated regions in the country and relies heavily on canal irrigation fed by the Mettur reservoir. When flows at Biligundulu fall short, the ability of Tamil Nadu to release water downstream is constrained, affecting standing crops and the planning of subsequent irrigation schedules. The state has repeatedly highlighted the human and economic cost of delayed or inadequate supplies.

At the same time, Karnataka faces its own pressures. Reservoir storage must meet drinking-water needs of major urban centres, environmental flows and the irrigation requirements of its own farmers. In a year of reduced inflows, every release decision involves difficult trade-offs. The regulatory framework is intended to balance these competing claims through transparent data and proportionate sharing.

The Supreme Court’s ongoing supervision of the dispute provides an additional layer of oversight. By listing the matter periodically and seeking status reports, the court has kept both states and the regulatory bodies accountable for compliance with existing directions. The August 31 hearing was expected to examine the latest affidavit and the response of Karnataka to the current release schedule.

The Path Forward

Resolution of the immediate backlog claim will depend on the court’s assessment of the hydrological data, the interpretation of pro-rata obligations, and the scope of the directions already issued by the Cauvery Water Management Authority. Longer-term management of the Cauvery basin continues to require improved data sharing, realistic assessment of distress conditions, and consistent application of the sharing formula across the entire water year.

Tamil Nadu’s latest petition underscores the continuing sensitivity of inter-state water allocation in a monsoon-dependent system. By placing a specific quantum of 17.604 tmcft before the Supreme Court and linking it to the livelihoods of delta farmers, the state has sought judicial intervention to close the gap between scheduled releases and cumulative entitlement. The outcome of the hearing will influence both the short-term availability of water for the current season and the evolving practice of distress sharing between the two states.

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