For the fourth consecutive year, Tamil Nadu realised a higher quantum of the Cauvery water in the just-concluded water year 2021-22.
Cumulatively, the State received about 281 tmc ft (thousand million cubic feet) between June 2021 and May 2022. In effect, it got 103.8 tmc ft more than the quantum of 177.25 tmc ft stipulated by the Supreme Court in the judgment.
After the Supreme Court’s verdict, the highest surplus realisation recorded by the State was in the water year immediately following the judgment. In 2018-19, the excess figure was 228.18 tmc ft, which remains the highest in the last four years. The next year, the State got 97.9 tmc ft more than the stipulated quantum. During 2020-21, the surplus was 34.13 tmc ft.
A perusal of the realisation data during the previous year reveals that the period from October to December (coinciding with northeast monsoon) accounted for 146 tmc ft, which was about 52% of the quantum realised in the previous year. The irony was that as per the monthly schedule drawn up by the Cauvery Water Disputes Tribunal and modified marginally by the Supreme Court, the State was to get only about 23.3% of the total annual quantum. In other words, 41.35 tmc ft was the quantum prescribed for the period out of the total of 177.25 tmc ft.
Also, as happened many times in the past, the period of southwest monsoon (June-September) saw the State experiencing a shortfall in the realisation of its due. Against the stipulated 123.14 tmc ft, the quantum received was 91.46 tmc ft. The deficit was 31.67 tmc ft.
Tamil Nadu got an unanticipated “bonanza” during January-May when it received about 44 tmc ft against 12.76 tmc ft. May witnessed the State netting around 22.96 tmc ft.
In terms of monthly realisation, November topped the list with around 71.57 tmc ft, followed by October, 48.28 tmc ft, and September, 33.14 tmc ft.
Keeping the Mettur dam as the reference point, the authorities have assessed that the total realisation during 2021-22 was approximately 272 tmc ft. About 236 tmc ft was discharged from the dam for irrigation in the year.