Explained | The Cauvery water conundrum

What did the Supreme Court rule with respect to the water sharing agreement between Karnataka and Tamil Nadu? Why are Karnataka’s farmers organisations and groups protesting against the directive and the government? What has been Tamil Nadu’s stance?

September 25, 2023 10:17 pm | Updated September 29, 2023 02:00 pm IST

Farmers stage a protest by standing in the Cauvery river over the Cauvery water release issue, in Trichy, Tamil Nadu on September 24.

Farmers stage a protest by standing in the Cauvery river over the Cauvery water release issue, in Trichy, Tamil Nadu on September 24. | Photo Credit: ANI

The story so far: On September 21, the Supreme Court asked Karnataka to continue releasing 5,000 cubic feet per second (cusecs) of water from the Cauvery river to Tamil Nadu for 15 days, in line with decisions of the Cauvery Water Regulation Committee (CWRC) and the Cauvery Water Management Authority (CWMA). This has evoked a strong reaction from certain sections of Karnataka, an upper riparian State.

How has the public reacted?

On September 22, the police arrested activists of the Federation of Karnataka Farmers’ Associations in Mysuru as they tried to barge into the Mysuru Zilla Panchayat premises to gherao Urban Development Minister Byrathi Suresh. The next day, several shops and business establishments remained closed in Mandya. A coalition of farmers and Kannada organisations have called for a bandh in Bengaluru on September 26, where the CWRC is scheduled to meet and review the situation of water availability and release.

How is the Cauvery water being shared?

The Cauvery Water Disputes Tribunal (CWDT)’s final award of 2007 and the Supreme Court’s judgment of February 2018 spell out the system for sharing the river water and the institutional mechanisms for ensuring implementation of the judicial verdicts. Pointing out that 740 thousand million cubic feet (tmc ft) of water would be available in the Cauvery basin in a normal year, the Court, which broadly adhered to the CWDT’s award, made the allocation for constituents of the basin as follows: Karnataka (284.75 tmc ft); Tamil Nadu (404.25 tmc ft); Kerala (30 tmc ft) and Puducherry (7 tmc ft). Ten tmc ft and four tmc ft have been set apart for environmental protection and inevitable escapages into the sea.

Of Tamil Nadu’s overall allocated quantity, Karnataka is to ensure 177.25 tmc ft, as per a monthly schedule, at Biligundulu, located on the inter-State border. Of this quantity, 123.14 tmc ft is to be given during the period from June to September, also marking the season of the southwest monsoon. Invariably, it is during this period that the Cauvery issue gets flared up, as the monsoon sometimes yields lower rainfall than anticipated.

The CWMA and its assisting body, CWRC, are in existence since June 2018 to oversee the implementation of the verdicts of the Tribunal and the Court.

Why are Karnataka’s farmers upset?

This year’s southwest monsoon has played truant, especially in south interior Karnataka, the region where the Cauvery river originates. Between June 1 and September 23, the region suffered a deficit rainfall of 27%, according to the India Meteorological Department. Kodagu of Karnataka and Wayanad of Kerala, which form part of the catchment of the Cauvery and its tributary, Kabini, registered a deficit rainfall of 43% and 56% respectively. Karnataka, in its application before Court, had stated that “...at the reservoir level, which covers a part of the catchment, the shortfall is 53.42%,” given the fact that the State has four reservoirs in the Cauvery basin.

Last week, Karnataka told the Supreme Court that the daily flow of 5,000 cusecs of water to Tamil Nadu was “against [its] interest.” The State, especially in urban areas like Bengaluru, was on “the brink of a drinking water crisis” whereas Tamil Nadu was in need of water for irrigation. It also added that the distress in Karnataka had increased in the past 15 days.

How serious is the situation in T.N.?

Being the lower-riparian State in the Cauvery basin, Tamil Nadu is mainly dependent on releases by Karnataka, particularly during the southwest monsoon, as it falls under the rain shadow region in the season. As per the data of the Central Water Commission available up to September 21, the State received 40.76 tmc ft, whereas it should have got 112.11 tmc ft in a normal year. Even after giving allowance for the failure of the monsoon and the quantum of shortfall as quoted by Karnataka, Tamil Nadu contends that it should have got at least 7.8 tmc ft more (as on September 12). It is in need of water for at least three lakh acres over which a short-term crop (kuruvai) has been raised. Already, there are reports of the crop being at risk of withering in many places.

However, the State will require, in the coming weeks, much more water for its long-term crop of 125-135 days (samba), which is normally raised over 15 lakh acres, providing livelihood opportunities to lakhs of landless labour. A substantial portion of the farming activity under the samba crop takes place during the northeast monsoon (October-December), which is much more unpredictable than the southwest.

In addition to serving irrigation, the Cauvery is the main source of drinking water for several districts in the State.

What is the way forward?

It is time that the CWMA along with the constituents finalised a distress-sharing formula. There have been differences over the choice of parameters that determine such a formula.

Making use of the present crisis, the Authority should take the initiative in convincing all the stakeholders in evolving the proposed formula.

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