Why Kerala And Tamil Nadu Are Locked In A Neyyar Water Dispute

A decades-old understanding over sharing the waters of the Neyyar river between Kerala and Tamil Nadu has turned into a prolonged legal dispute, ending an arrangement that functioned without a formal agreement for nearly four decades.

The disagreement centres on water from the Neyyar dam in Kerala, which was historically supplied to irrigate farmland in Tamil Nadu's Vilavancode taluk. Although the irrigation project was conceived as a symbol of cooperation between neighbouring states in the 1950s, Kerala halted the water supply in 2004, triggering a dispute that eventually reached the Supreme Court.

How An Informal Water-Sharing Arrangement Worked

The Neyyar irrigation project began in 1951 when the region was still part of the erstwhile Travancore-Cochin State. Following the States Reorganisation Act of 1956, the project evolved into a joint venture between Kerala and the then Madras State, now Tamil Nadu. The Neyyar dam was commissioned in 1959, while the Left Bank Canal was designed to carry water into Tamil Nadu's Vilavancode region.

The project was expected to irrigate nearly 36,000 acres of farmland, including around 9,000 acres in present-day Kanniyakumari district. Unlike many inter-state river arrangements, however, the two states never signed a formal water-sharing agreement. Instead, they operated under an unwritten understanding that Kerala would release up to 150 cusecs of water for irrigation after meeting its own requirements.

Tamil Nadu financed and constructed the canal infrastructure within its territory, while Kerala continued releasing water through the canal from around 1965. Despite the absence of a written accord, the arrangement functioned smoothly for almost 40 years and was often viewed as an example of cooperative federalism.

Why The Dispute Began

The relationship began to fray in 2003 after Kerala experienced a significant rainfall deficit. Around the same time, disagreements also emerged over proposals to interlink rivers and transfer water from Kerala's west-flowing rivers to Tamil Nadu. Kerala strongly opposed these proposals, arguing that they could create complex water management challenges and should not proceed without the consent of affected states.

Against this backdrop, Kerala enacted legislation to bring inter-state river agreements under greater state oversight. In February 2004, it stopped supplying Neyyar water to Tamil Nadu through the Left Bank Canal, describing the decision as necessary to safeguard its own water resources. Tamil Nadu, which had relied on the supply for irrigation, described the move as abrupt.

Subsequent attempts to revive the arrangement failed to produce a consensus. Kerala later indicated that it was willing to supply water if its value was recognised, but disagreements widened over whether the Neyyar qualifies as an inter-state river and under what legal framework the sharing should continue.

With negotiations yielding little progress, Tamil Nadu approached the Supreme Court in 2012. The legal proceedings have since continued, with witness examinations completed and arguments expected to determine the future of the long-standing dispute.

The prolonged impasse has had lasting consequences for farmers in Vilavancode. Many cultivators who once depended on Neyyar water for paddy cultivation have shifted to crops such as coconut, banana and rubber, while others have converted agricultural land into residential plots.

What was once celebrated as a model of cooperation between Kerala and Tamil Nadu has today become another unresolved chapter in India's long history of inter-state river disputes.