After two successive years of excess realisation of its share of Cauvery water during the crucial southwest monsoon (June-September), Tamil Nadu has ended this year’s season with a deficit.
Against a prescribed quantity of 123.14 thousand million cubic feet (tmc ft) for the period, the State got 120.24 tmc ft, marking a shortfall of 2.895 tmc ft. What is significant is that at the beginning of September, the cumulative shortfall for the season was around 11.3 tmc ft, which has come down since.
Of the total quantity received this year, about 103 tmc ft was realised by the State in August and September.
A significant pattern
A perusal of data on the inflow of Cauvery river water in the last 10 years reveals a striking feature, which has been a pattern for the last 30 years. In six of the last 10 years, the State got less than its share of Cauvery water. Since 1991, there have been 19 such years when Tamil Nadu realised less than its share of water during June-September, as stipulated by the Cauvery Water Disputes Tribunal in its interim (1991) and final (2007) orders and by the Supreme Court in February 2018.
According to the tribunal’s interim order, of an overall annual quantity of 205 tmc ft, 137 tmc ft was to be received by Tamil Nadu during June-September. In the tribunal’s final order, the figure was 134 tmc ft and in the Supreme Court’s judgment, 123.14 tmc ft.
As on Thursday morning, the water level in the Mettur dam stood at 96.64 ft (full level- 120 ft), with its storage being 60.573 tmc ft (capacity- 93.47 tmc ft). Inflow to the dam was 8,343 cubic feet per second (cusecs) and the discharge 6,850 cusecs, including 6,000 cusecs through the river.
What is of additional comfort to the State is that the Bhavanisagar dam, also in the Cauvery basin, is close to the brim with a storage of around 30 tmc ft, against a capacity of 32.8 tmc ft.
