1950s After Indian independence in 1947, and the
reorganisation of the Indian states based on linguistic lines in 1956, the regions of the ertswhile territories of Mysore and Madras largely became part of
Mysore State (which was renamed as Karnataka later) and
Madras State (which was renamed as Tamil Nadu later) respectively. Parts of the Kaveri basin which earlier formed part of Madras Presidency went to
Kerala, and the
union territory of
Puducherry. The reorganisation also resulted in some of the river's tributaries to be in Kerala. As a result, both Kerala and Puducherry became invested in the sharing of the waters of the Kaveri river. In 1971, petitions were submitted to the Supreme Court requesting that the union government should send the dispute to a tribunal under the Interstate River Water Disputes Act of 1956. It was also agreed to form a Cauvery Valley Authority which would be headed by a
Central Water Commission member, but this committee was never established due to political reasons. As Karnataka was forced to accept the interim award, widespread
demonstrations and violence broke out in parts of Karnataka, which resulted in targeting of
Tamil families, with many forced to flee from
Bangalore in fear of being attacked and lynched by pro-Kannada activists with the behest of the state government. The violence continued in the Tamil populated parts of Bangalore for nearly a month before it was brought in control. In 1995, after a poor
monsoon, Karnataka was not able to fulfill the obligations of the interim order of CWDT, and had a cumulative deficit of 26.6 tmcft in May and June. Tamil Nadu approached the Supreme Court demanding the immediate release of at least 30 tmcft of water, and the Supreme Court asked the state to approach the tribunal. The tribunal recommended that Karnataka release 11 tmcft of water by December and 17.4 tmcft by May next year. Tamil Nadu now went back to the Supreme Court demanding that Karnataka be forced to obey the tribunal's order, and the court recommended that the
prime minister intervene to find a solution. The prime minister convened a meeting with the chief ministers of the two states on 30 December, after which it was agreed that Karnataka would release 6 tmcft instead of the 11 tmcft that the tribunal ordered, and the state complied with it. The order passed during a similar crisis in 1995-96, had not addressed how future conflicts would be handled. With Tamil Nadu demanding that Karnataka honour the interim award and release to Tamil Nadu its proportionate share, and Karnataka on the other hand refusing to do so given that the water levels were hardly enough to meet its own demands, the case went to the CRA, and later the Supreme Court. The CWDT announced its final verdict on 5 February 2007. According to its verdict, Tamil Nadu was awarded 419 tmcft of the Kaveri river waters while Karnataka got 270 tmcft, with Kerala and Puducherry getting 30 tmcft and 7 tmcft respectively. It also laid down the terms for monthly release of water from Karnataka to Tamil Nadu. The tribunal directed that the upper riparian states should not engage in any activities detrimental to the other parties. It also laid down that, in case of a reduction in water levels, the allocation of the states shall be reduced proportionately.
2010s 2012 On 19 September 2012, the CRA ordered Karnataka to release 9,000
cusecs of water per day to Tamil Nadu. However, Karnataka felt that this was impractical due to the drought conditions prevailing because of the failed monsoon, and filed a
review petition before the authority on 21 September, seeking review of its 19 September ruling. On 28 September 2012, the Supreme Court criticized the Karnataka government for failing to comply with the directive of the CRA. Karnataka complied with the order, which led to wide protests and violence in parts of Bengaluru. On 4 October 2012, the Karnataka government filed a review petition before the Supreme Court seeking a stay on its 28 September order directing it to release 9,000 cusecs of water everyday to Tamil Nadu, until 15 October. On 6 October, several pro-Kannada organisations, called for a
bandh in protest against the Cauvery water release. On 8 October, the Supreme Court ordered that the release of 9,000 cusecs had to be continued and asked the CRA to ensure the same. However, after the CRA rejected the review plea from Karnataka, the Karnataka government stopped the release of Kaveri water to Tamil Nadu on the same day. On 17 October, Tamil Nadu made a fresh plea in the Supreme Court, reiterating its demand for appropriate directions to be issued to Karnataka to release the shortfall of 48 tmcft of water as per the distress sharing formula stipulated by the CWDT. On 15 November 2012, the CRA directed the Karnataka government to release 4.81 tmcft of water to Tamil Nadu between 16 and 30 November. On 6 December, the Supreme Court further directed Karnataka to release 10,000 cusecs of water to Tamil Nadu. It further questioned the union government as to why the final decision of CWDT, which was given in February 2007, was yet to be officially gazetted.
2013 On 20 February 2013, the union government notified the final award of CWDT. In case of water availability of 50% or below from a normal water year when the total water availability in the basin was 740 tmcft, the allocation would be reduced proportionately. The allocation would be calculated along with unused water in the reservoirs at the beginning of the year in the basin. While Karnataka was to release stipulated amount of water monthly to meet the allocation of 419 tmcft of water to Tamil Nadu, Tamil Nadu was stipulated to release at least 10 tmcft of water for maintaining minimum
environmental flows downstream of
Lower Coleroon Anicut and supply 7 tmcft to Puducherry in a normal water year. Kerala was allowed to use 21 tmcft from
Kabini River basin, 6 tmcft from
Bhavani River basin and 3 tmcft from
Pambar River basin in a normal year. The award also let Karnataka and Tamil Nadu use all the excess water available in its area after the stipulated allocation during a normal year. Any water going waste to sea in excess of 4 tmcft (other than 10 tmcft minimum environmental flows) forms part of the utilisable water share of Tamil Nadu. Based on the river basin water data available from the year 1934 to 1971, the tribunal had estimated the average water yield in the total river basin as 767 tmcft with 47% dependability. The water used in the Kaveri delta in Tamil Nadu and Puducherry was nearly 280 tmcft annually which is the tail end water use in the river basin and its regenerated water either goes to sea or outside the basin. In response to the petition filed by Tamil Nadu earlier, the Supreme Court on 10 May 2013 issued an interim direction to the union government to establish an interim supervisory committee to implement the tribunal order till the constitution of the Cauvery Management Board (CMB) as stated in the tribunal order. The union government issued the gazette notification on 22 May 2013 establishing the supervisory committee. As per the Interstate River Water Disputes Act, the committee has powers similar to an authority/board established by the
Indian parliament.
2016 Karnataka later proposed a dam project at
Mekedaatu, which led to Tamil Nadu raising objections to it. In August 2016, Tamil Nadu approached the Supreme Court, seeking direction to Karnataka to release 50.052 tmcft of water, which was pending as per the order of the CWBT. Karnataka had declined to release water and cited low reservoir levels. On 2 September, the Supreme Court asked Karnataka to consider Tamil Nadu's plea on humanitarian grounds and release water and advised both states to maintain harmony. On 5 September, Karnataka informed the Supreme Court that it can release 10,000 cusecs of water per day, while Tamil Nadu demanded 20,000 cusecs per day. The Supreme Court ordered Karnataka to release 15,000 cusecs per day to Tamil Nadu for the next ten days. However, violence erupted in Karnataka following a bandh called by pro-Kannada organisations, which resulted in wide spread arson, and rioting. The violence resulted in two deaths, and curfew was imposed in parts of Bengaluru. On 12 September 2016, Karnataka cited the violence as a reason for its inability to release water before the Supreme Court. The Supreme Court modified the 5 September order, directing Karnataka to release 12,000 cusecs of water till 20 September 2016, and ordered the formation of a Cauvery Supervisory Committee within the next five days. On 19 September 2016, the committee ordered Karnataka to release 3,000 cusecs per day from 21 September 2016 to 30 September 2016. On 20 September 2016, the Supreme Court directed Karnataka to further release 6,000 cusecs of water from 21 September 2016 to 27 September 2016 and directed the union government to set up the Cauvery Management Board in order to provide a permanent solution for the dispute. However, in a special session of the
Karnataka Legislative Assembly held on 23 September, a resolution was passed not to release water to Tamil Nadu, defying the Supreme Court's order. On 27 September, the Supreme Court passed a revised order to Karnataka to give 6000 cusecs of water to Tamil Nadu for three days, which was not honoured by Karnataka. On 30 September, the Supreme Court gave Karnataka an ultimatum and ordered 6,000 cusecs of water to be released during the next six days. It asked the union government to set up the Cauvery Water Management Board (CWMB) by 4 October and report back on 6 October with assessment of water levels. On 1 October 2016, Karnataka filed for review petition against the order. After a special legislature session on 3 October, the Karnataka government decided to release water for agricultural purposes. On 4 October, the Supreme Court directed Karnataka to further release 2,000 cusecs of water daily to Tamil Nadu from 7 to 18 October.
2018 As instructed by the Supreme Court, the Cauvery Water Management Authority (CWMA) was created by the union government on 1 June 2018. The nine-member Cauvery Water Regulation Committee was created three weeks later. The Supreme Court on 9 January 2018 declared that it would pronounce its verdict clearing all the pending cases related to river water dispute within a month. On 16 February 2018, the Hon'ble Supreme Court pronounced its verdict, and allocated 404.25 tmcft to Tamil Nadu and 284.75 tmcft to Karnataka, while the allocations for the others remained the same. It also mandated the union government to formally constitute the Cauvery River Management Board (CRMB) within 40 days for implementing the CWDT award and its verdict. Headquartered in Delhi, the CWMA became the sole body to adjudicate the river water dispute, and to oversee the allocation. The authority was assisted in the discharge of its functions by regulatory committee consisting of senior judges of the Supreme Court.
2020s In August 2023, Tamil Nadu requested Karnataka to release 24,000 cusecs of water per day, citing the need to irrigate crops. However, Karnataka refused, citing water shortage. Protests erupted in Karnataka, with agitators demanding that Karnataka stop releasing more water, while farmers in Tamil Nadu protested against Karnataka, demanding the release of water. In September 2023, the CWMA directed Karnataka to release 5,000 cusecs of water per day for 15 days. Karnataka complied, but refused to release any further water after the period. Tamil Nadu filed a contempt petition against Karnataka in the Supreme Court, alleging that the state had violated the court's orders. The Supreme Court the state to approach the CWMA and asked the CWMA to submit a report on the situation. Later, the Karnataka government appealed against the CWMA decision to provide 3,000 cusecs of water per day, and said that it is open to discuss with Tamil Nadu to arrive at a mutually agreeable solution.The government has also said that it is willing to negotiate with Tamil Nadu to find a mutually agreeable solution. == Summary ==