Tamil Nadu’s claim of Cauvery backlog and the Supreme Court’s response | Explained

Cauvery river flows at Sangama. File | Photo Credit: Mural Kumar. K

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.