Tamil Nadu: Account for Bengaluru’s Cauvery water supply fully; Karnataka: We know how to use our share

Bengaluru: Determined to secure what it claims is its rightful share of Cauvery water, Tamil Nadu has now turned its attention to Bengaluru’s water supply.Alleging that Karnataka has been supplying Cauvery water to parts of Bengaluru that fall outside the Cauvery basin, Tamil Nadu has urged the Cauvery Water Management Authority (CWMA) to account for this volume of water while calculating Karnataka’s utilisation.It has also sought details of tank-filling schemes under the minor irrigation department and lift irrigation schemes that draw water directly from the Cauvery river and its canals.With forecasts of a weak southwest monsoon due to the developing El Niño conditions, Tamil Nadu has intensified its scrutiny of Cauvery water supplied to Bengaluru, which consumes about 24 tmcft annually—around 21% of the combined live storage capacity of 115 tmcft in Karnataka’s four major Cauvery basin reservoirs.Ahead of the 53rd meeting of CWMA scheduled for July 15, Tamil Nadu has urged the authority to account for every drop of Cauvery water utilised by Karnataka. It has specifically requested CWMA to include the water supplied to the areas of Bengaluru located outside the Cauvery basin while calculating Karnataka’s utilisation, an issue it had also raised during the authority’s meeting in June 2026.Arguing that Cauvery water is being supplied to areas beyond the river basin, Tamil Nadu stated: “The entire quantity of Cauvery water drawn to meet the drinking water requirements of Bengaluru areas located outside the Cauvery basin should be treated as 100% utilisation by Karnataka and duly accounted for while calculating the state’s water use.”

According to Tamil Nadu, parts of north and east Bengaluru fall within the Pennar and Ponnaiyar basins, and diverting Cauvery water to these regions violates the spirit of the river water-sharing arrangement while affecting downstream flows. It has therefore sought inclusion of this quantity in Karnataka’s utilisation for yield calculations.Tamil Nadu has also questioned Karnataka’s practice of lifting Cauvery water directly from the river and its canals to fill tanks maintained by the minor irrigation department under various lift irrigation schemes.It has requested CWMA to direct Karnataka to furnish details of all minor irrigation tank-filling projects and lift irrigation schemes that draw water directly from the river system, contending that such withdrawals affect natural inflows into the Cauvery reservoirs and consequently reduce water available to downstream Tamil Nadu.However, Karnataka water resources minister Ramalinga Reddy strongly rejected Tamil Nadu’s objections, asserting that the upper riparian state is fully entitled to decide how to utilise the water allocated to it.—-------------QuoteTamil Nadu has no authority to dictate how Karnataka should utilise its allocated share of Cauvery water. We are not violating any provision of the water-sharing arrangement. The water allocated to Karnataka is being planned and utilised scientifically and judiciously. How we use our legally allocated share is entirely the state’s prerogative-Ramalinga Reddy, water resources minister, Karnataka