Tamil Nadu's claim of Cauvery backlog and the Supreme Court's response

The failure of the southwest monsoon (June-September) this year is the primary reason for the current round of disputes between Karnataka and Tamil Nadu

The story so far: On October 12, the Supreme Court questioned Tamil Nadu on how Karnataka could be expected to make good the backlog in the release of Cauvery water when the latter was itself grappling with water scarcity and drought conditions. A Division Bench of the Court made this observation while reserving its order on an application filed by Tamil Nadu, which contended that as on October 6, it suffered a shortfall of around 11.7 thousand million cubic feet (tmc ft) in realisation of its share of the Cauvery water at Biligundulu, the inter-State border measuring point.

What has caused the present situation?

The failure of the southwest monsoon (June-September) this year is the primary reason for the current round of disputes between the upper riparian and lower riparian States. During the period from June 1 to October 7, the Cauvery catchments recorded a negative departure of 30% from the normal rainfall. In particular, the deficit rainfall in the catchment downstream of Krishnaraja Sagara (KRS) and Kabini, up to Biligundulu, was 43%. Against the quantity of 57.568 tmc ft to be realised during the corresponding period in such circumstances, the realisation was 45.849 tmc ft. This was the figure worked out by the Cauvery Water Regulation Committee (CWRC), the main arm that assists the Cauvery Water Management Authority (CWMA), the implementation mechanism for the final award of the Cauvery Water Disputes Tribunal, as modified by the Supreme Court. Tamil Nadu had, too, in its latest application, cited the figure of the CWRC. In fact, at the Authority's last meeting on October 8, the State demanded that a backlog of 15.02 tmc ft be made good by Karnataka.

How has Karnataka reacted to this demand?

Karnataka stated in the Supreme Court its difficulties in clearing the backlog.

Even at the CWMA meeting last week, the State, referring to the current spell of drought, told the Authority that its four reservoirs in the Cauvery basin had experienced a 54% deficit in cumulative inflows. It had to prioritise its limited water storage for drinking water requirements and environmental flows, both of which would account for 45 tmc ft. Submitting to the Court that it was complying with the CWMA's latest direction of providing 3,000 cubic feet per second (cusecs) for 15 days from October 9, the upper riparian State argued that Tamil Nadu had the advantage of the impending northeast monsoon (October-December), which was expected to replenish its reservoirs in the Cauvery basin.

What is the stand of Tamil Nadu?

The lower riparian State has strongly complained to both the Authority and the Court that the quantum of 3,000 cusecs is "grossly inadequate and does not redress the substantial backlog" already accumulated. Its point is that as per the pro-rata, the flow to be ensured at Biligundulu is about 3,500 cusecs in October, and not 3,000 cusecs. Any decision to reduce the flows due to Tamil Nadu would have serious consequences for the paddy crop during the current Samba cultivation season and the livelihood of the farmers in the Cauvery delta. Besides, any meteorologist would point out that the northeast monsoon, which is more unpredictable than the southwest monsoon, is "highly variable both spatially and temporally," according to M. Rajeevan, Distinguished Scientist, Union Ministry of Earth Sciences, and 16 other scientists in a 2002 monograph on the northeast monsoon.

How has the Court responded to the two States' arguments?

The Division Bench, headed by Justice Vikram Nath, made a statement that "a backlog can be covered only when there is excess water. If there is less rainfall and there is scarcity, how do you expect them to fulfil the backlog? They are also reeling from water scarcity. If they have excess water and are not giving it to you, then only can you recover the backlog." It also reserved its order on the application.

What is the way forward?

The World Meteorological Organization (WMO) has cautioned countries that El Niño, having been firmly established, may raise risks of extreme weather in 2027. Moreover, the spells of deficit rainfall will continue to be experienced in the years to come. It is time that the two principal riparian States started collaborating with each other in planning and carrying out their agricultural operations in a coordinated manner. The Union government should begin its work on establishing a River Basin Organisation for the Cauvery, as the present institutions - the CWMA and the CWRC - are meant only for ensuring the implementation of the final award of the Cauvery Water Disputes Tribunal, as modified by the Supreme Court in February 2018. The current water allocation arrangement would be valid only up to 2033, going by the Court's ruling eight years ago.