Indian Supreme Court Ruling: An End to the Cauvery Water Dispute?

28 February 2018 Mervyn Piesse, Research Manager, Global Food and Water Crises Research Programme


The sharing of water from the Cauvery River has been a contentious issue since the 1890s, and while numerous settlements have been reached, none have comprehensively resolved the issue. Tamil Nadu historically used more water than Karnataka, the upstream riparian. To provide its burgeoning agricultural sector with a more stable supply of water, the Mettur dam was built in Tamil Nadu in 1924 and an agreement was signed with Karnataka that authorised it to also expand its agricultural area. When the accord lapsed, in 1974, Karnataka argued that the agreement restricted its ability to expand its agricultural land and it began building reservoirs further upstream, leading to disputes between the two states.

On 16 February the Indian Supreme Court ruled that the state of Karnataka can withdraw up to 284.75 thousand million cubic feet (TMC) of water from the river each month for the next 15 years – 14.75 TMC more than under the old quota system. Tamil Nadu, on the other hand, is allocated 177.25 TMC per month– 14.75 TMC less than under the old agreement.

Cauvery Basin


It is estimated that the annual discharge of the Cauvery is 21.3 billion cubic metres (BCM), but the flow varies substantially depending on prevailing weather conditions. Demand for the river’s water has also increased in the past two decades due to the promotion of water-intensive crops, such as rice and sugar cane, and a 30 per cent increase in population. The amount of river water flowing in to the Bay of Bengal has reportedly declined due to the increase in water consumption along the course of the river. Seawater intrusion has become a more regular occurrence in the past few decades and many locals have turned to shrimp fishing in an attempt to adapt to the new environmental reality.

Numerous tribunals have been convened to share the limited water resources between the states of southern India.  A tribunal ruled in 2007 that Tamil Nadu’s allotment of the river was to be set at 12 BCM and that Karnataka was entitled to 7.6 BCM. It took six years for the national government to approve the deal, however, and Karnataka continued to resist the terms of the tribunal regardless. While the Supreme Court has granted the national government six weeks to establish the Cauvery Management Board (CMB), which will oversee the agreement, it is possible that the terms of the new deal will be similarly rebuffed.

The Chief Minister of Karnataka announced that he plans to challenge the Court’s order on the establishment of the CMB as he believes that his state will not be treated fairly by the board. Tamil Nadu, meanwhile, wants the board to be set up as soon as possible to pressure Karnataka to accept the Supreme Court verdict ‘in letter and spirit’.

The adoption of the ruling could lead to unrest, however, as the decisions of previous tribunals have angered residents of one or both states. In 2016, for instance, after the Supreme Court directed Karnataka to release 425 cubic metres of water per second from its reserves to Tamil Nadu, violent protests broke out in Bangalore. The amount was later reduced to 300 cubic metres per second.

The Supreme Court’s ruling focusses exclusively on the supply of water. Efforts to reduce the growing demand for water will further strengthen southern India’s water security. A third of the farmland in Tamil Nadu is used to grow rice and efforts to encourage farmers to grow less thirsty crops have been met with resistance. State subsidies on the extraction of water for agricultural purposes also encourage wasteful water practices. An increase in the adoption of water saving technology, such as drip irrigation, will help to reduce water wastage and thereby ease the growing demand for water.

The CMB, if it is established, will provide Karnataka and Tamil Nadu with a forum to air their grievances over the sharing of the Cauvery River. The board will need to consider the social implications of any decision it makes given the long history of social unrest that often accompanies changes to the water sharing regime. The establishment of the board will help with the supply-side of the water sharing regime, but the demand-side will also need to be addressed if the region’s water is to be managed comprehensively.

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