With the current water year 2023-24 coming to an end this month, the overall realisation by the State in the year may end up next to the lowest figure of 69 tmc ft (thousand million cubic feet) during 2016-17 since 1974, the year in which the 1924 inter-State (Karnataka and Tamil Nadu) agreement was said to have lapsed.
For the purpose of calculation, the reference point is Biligundulu on the inter-State border where the Central Water Commission (CWC) has a facility to measure the flows.
As on April 30, the cumulative receipt since June 1, 2023 was about 78.8 tmc ft. This was marginally higher than around 75.6 tmc ft, which was recorded during 2003-04. The current water year will, in all probability, mark the third occasion of Tamil Nadu’s annual quota of the Cauvery water not exceeding the 100-tmc ft mark. This can change only when the Cauvery catchment in Kerala and Karnataka experience heavy rainfall immediately before the onset of Southwest monsoon in the last week of this month.
Since 2000, there were two more years in which Tamil Nadu’s annual share crossed the 100-tmc ft by a small margin. In 2012-13, the State got 100.4 tmc ft and in 2002-03, the figure was 109.9 tmc ft.
On the morning of Thursday (May 2), the State’s three reservoirs in the Cauvery basin – Mettur, Bhavanisagar and Amaravathy – had a cumulative storage of 23.96 tmc ft against the total capacity of 130.31 tmc ft.
Meanwhile, the Cauvery Water Regulation Committee (CWRC), in its meeting on Wednesday, did not even consider the State’s request of directing Karnataka to ensure the release of at least five more tmc ft for the purpose of environmental flows.
As per the Cauvery Water Disputes Tribunal’s final order, as modified by the Supreme Court, the upper riparian State should release 2.5 tmc ft a month during February to May. At the end of April, the State realised barely two tmc ft against 7.5 tmc ft.
As for other major irrigation reservoirs in the State, the present storage of Parambikulam network of dams comprising Sholayar, Aliyar and Thirumurthy was lower than what was there on the same day last year. The Sathanur-Krishnagiri pair too was in a similar position.
The only consolation was the storage of dams located in southern parts of the State. Starting from Vaigai to Perunchani, the current storage was higher than that of the corresponding period last year.
