Cauvery committee chief asks T.N., Karnataka to come up with distress-sharing formula

Rejecting the criticism against the CWRC and CWMA, Mr. Gupta recalled that during the water year of 2023-24, the two bodies had worked out a distress-sharing mechanism. 

As regards the CWRC’s calculation of 3,500 cubic feet per second (cusecs) to be released by Karnataka for the next 15 days to Tamil Nadu, he said this had been done taking into account rainfall pattern, net inflow to four reservoirs of Karnataka in the river basin, comparison of the current situation with the long-term average, and inputs from the Meteorological Department.

For Biligundlu – the gauge and discharge (G&D) site being used by the Central Water Commission (CWC) for the measurement of the river flow on the border of Karnataka and Tamil Nadu – to realise the prescribed quantity, Karnataka had to release 6,000 cusecs to 6,500 cusecs from its four reservoirs in the Cauvery basin.

In view of the intermediate catchment (between the Krishnaraja Sagar (KRS)-Kabini dams in Karnataka and Biligundlu) being “very dry,” the upper riparian State had to release much higher than the prescribed quantity so as to enable Biligundlu to realise 3,500 cusecs. On average, the yield from the intermediate catchment would be 80 thousand million cubic feet (tmc ft) annually. “But this year, in July, it is completely dry,” the CWRC chief observed. 

Pointing out that the long-term average had been calculated on the basis of 30-year data, Mr. Gupta said there had been a 60% deficit for the Karnataka reservoirs with regard to net inflow, and 90% deficit at Biligundlu, “where the flow has been around 150 cusecs to 200 cusecs only.” Besides, this month, the cumulative realisation had not even touched the one-tmc-ft mark.

As of July 27, the realisation at Biligundlu was 0.6 tmc ft. against 27.2 tmc ft., as prescribed by the CWDT in the final award and which was, in turn, modified by the Supreme Court in 2018. The cumulative shortfall in realisation since June 1 was around 33 tmc ft.  What was received at Biligundlu from June 1 to July 27 was about 3.6 tmc ft. compared to the stipulated quantity of 36.4 tmc ft. 

However, the CWRC, which took into account the current condition, had assessed that the net deficit, as of now, was 9.8 tmc ft., of which 50% could be offset by Karnataka, the panel chief said. This was why the Committee had arrived at a total quantity of 4.5 tmc ft to be realised over the 15-day period.