The Cauvery river water dispute reached the Supreme Court yet again on August 26, when it admitted a petition filed by Tamil Nadu.

The South Indian state asked the court to direct its neighbour, Karnataka, to release water due to it according to the 2007 order of the Cauvery Water Disputes Tribunal – which came after a protracted legal battle between the two states about sharing water from the river.

In its petition, Tamil Nadu has accused Karnataka of diverting water from the river for purposes other than irrigation and drinking, thereby denying its neighbour its rightful share of the resource. This water is crucial for farmers in the Cauvery delta, spread across seven districts of Tamil Nadu, to sustain their kuruvai or summer crop cycle, when they usually grow paddy.

Karnataka, on its part, has consistently cited inadequate supply as the reason for failing to release the water. When a delegation of Tamil Nadu farmers met him last week, Karnataka Chief Minister Siddaramaiah categorically rejected their demand for water, citing low rainfall in the catchment areas.

The court will take up the petition for hearing on Friday.

Genesis of the trouble

This is just the latest chapter of the dispute over water-sharing between the two states, which has been going on since the 1970s and has its origin in two agreements signed between the erstwhile Madras Presidency and the Princely State of Mysore in 1892 and 1924, which lapsed in 1974.

The Cauvery river originates in Karnataka and goes on to flow through Tamil Nadu, before meeting the Bay of Bengal. In the 1960s and ’70s, Karnataka built four dams across the river: Kabini, Harangi, Hemavathi and Suvarnavathy. This purportedly diverted some of the water from flowing into the lower riparian state of Tamil Nadu.

Tamil Nadu then asked the Congress-ruled government at the Centre to form a tribunal to look into the diversion of water and ensure that it gets its due share. When the Centre did not heed to its demand, it approached the Supreme Court, which, in May 1990, ordered the creation of the Cauvery Water Disputes Tribunal.

In 1991, the tribunal passed an interim award ordering Karnataka to release 205 tmc ft (an acryonym for one thousand million cubic feet) of water every year to Tamil Nadu. This prompted strong and in some places, violent protests in Karnataka, which delayed the release of water. In response, in 1993, J Jayalithaa, who was the chief minister of Tamil Nadu in that year too, held a fast at Chennai’s (then Madras) Marina Beach, which lasted 80 hours, before the Centre assured that it would look into the state’s concerns.

For the next 14 years, both sides continued to spar over water-sharing and the legal battle continued, until the Cauvery Water Disputes Tribunal announced its final award in 2007. The tribunal pegged the total availability of water in the Cauvery at 740 tmc ft, of which Tamil Nadu was to receive 419 tmc, Karnataka 270 tmc, Kerala 30 tmc and Puducherry seven tmc. The tribunal also allotted 10 tmc for environment protection and adjusted four tmc for run off to the sea. The order meant that Karnataka would have to release 192 tmc ft of water from its catchment to Tamil Nadu every year.

The award took into account the irrigation and drinking water needs of all the states involved. However, the tribunal failed to comprehensively and authoritatively state how the water was to be shared in "distress years", when the flow in the Cauvery was deficient owing to inadequate rainfall.

The tribunal stated that if water had been deficient in a particular year, the resource would have to be shared "proportionately" between the states – meaning Tamil Nadu would continue to get 56% of the water, Karnataka 36% and Kerala 4%.

Room for argument

On the face of it, this seems reasonable, but the problem arises when Karnataka claims, as it did this year, that the water in the river is not even enough to meet its drinking needs.

For instance, in its latest petition before the Supreme Court, Tamil Nadu said that it had not received the mandated amount of water from the Cauvery between June and August, resulting in a shortfall of about 50 tmcft.

Tamil Nadu has complained that the last time Mettur dam, the point where Cauvery enters the state in Salem, was opened on June 12 (as has been the custom in the state) was in 2011. Since Tamil Nadu receives a bulk of its rainfall in October, during the retreating North East monsoon, it relies on Karnataka for water, especially for irrigation, during this period.

Officials in the Karnataka Water Resources Department, however, have said that the demand for June-August could not be entertained because it was based on a year in which normal rainfall had been received. At a press conference after an all-party meeting in Karnataka convened by the government on August 27 after the Supreme Court agreed to hear Tamil Nadu’s petition, Siddaramaiah said that while Karnataka expected an inflow of 192 tmc ft of water in Kabini, Harangi, Hemavathi and Krishnaraja Sagar dams by August 24, only 108 tmc ft had accumulated.

Of this, the dams had only 51 tmc of usable water and hence it could not meet Tamil Nadu’s demand, he said.

A quick glance at the Indian Meteorological Department's website seems to bear this out. Hasan and Kodagu, two important catchment districts for the Cauvery in Karnataka, have respectively recorded a 23% and 27% rainfall deficiency.

However, a senior official in Tamil Nadu's Public Works Department said that Karnataka has consistently used this “modus operandi”. In the latest petition filed before the Supreme Court, Tamil Nadu said that Karnataka diverted the water towards "undeclared projects" and then showed a deflated figure in the reservoirs to deny Tamil Nadu its rightful share.

"The release of water from the Mettur dam in summer has been delayed over the last five years,” the official said. “Currently, the water stands at 71 feet, with inflows being a paltry 7,200 cusecs. We are discharging about 1,250 cusecs, but this is not for irrigation. Unless we get water by the first week of September, the summer crop will be affected.”

Mettur has a storage capacity of 120 feet, but water is released for irrigation only when the level exceeds 90 feet.

Farmers bear the brunt

As the state government trade charges and battle it out in court, farmers in Tamil Nadu have borne the biggest brunt the crisis. Former legislator and Communist Party of India (Marxist) member, K Balakrishnan, who led the delegation of farmers that met Siddaramaiah last week, stated that the farmers have faced increasing debts and a drastic reduction in their income due to the loss of the summer crop.

For long, Cauvery delta farmers had been managing three paddy crops a year. "In the last few years, some have managed to grow only one crop,” Balakrishnan said. “While big farmers cultivate with borewell pumps, those with small holdings are the worst affected.”

Balakrishnan said the tribunal's failure to work out a more expansive formula for distress years has given an excuse to Karnataka to withhold supply repeatedly. "Even in a bountiful year, there is resistance from various groups in Karnataka to open its dams,” Balakrishnan said. “To keep such groups happy, the government plays along," he said.

The CPM leader added that there was a loss of about 1.8 lakh hectares of cultivation in the Cauvery delta due to non-release of water by Karnataka.

Politics over water

While erratic monsoons may have exacerbated the dispute between the two states, political interests have kept a lasting solution at bay.

As the Congress and the BJP have a bigger presence and hence a larger stake in Karnataka than in Tamil Nadu, the governments led by these parties at the Centre have been slow in implementing crucial orders in the dispute.

For instance, though the tribunal delivered its final award in 2007, it took six years for the United Progressive Alliance government to notify it in its gazette. The tribunal envisaged the formation of a Cauvery Management Board to regulate water release and avoid dispute, but that has has not been put set up.

In 2013, the All India Anna Dravida Munnetra Kazhagam government in Tamil Nadu moved the Supreme Court over the delay in setting up the board. Karnataka has since hardened its stand against the setting up of the board and has appealed to the Centre not to take a call on it in its independent capacity till the court comes to a decision.

Moreover, unlike in Karnataka, where parties come together to fight for the state's rights, the feud between the AIADMK and the opposition Dravida Munnetra Kazhagam has made coordinated action impossible. For instance, while Karnataka has seen several all-party-meetings on the issue, there has been no such attempt in Tamil Nadu for at least six years now.

Adding fuel to the fire is the attempt by Karnataka to build another dam across the Cauvery at Mekedatu in Kanakapura town to meet Bengaluru's drinking-water needs and to produce hydro electricity.

Balakrishnan said the two governments have to resolve the matter among themselves. "Keeping the interest of farmers on both sides in mind, the governments should initiate a serious dialogue,” he said. “This is the only way to find a permanent solution.”