CHENNAI: Amid a war of words between Tamil Nadu and Karnataka over the controversial Mekedatu project, the Central Water Commission (CWC) has returned the Detailed Project Report (DPR) submitted by Karnataka, saying the proposal does not conform to the Cauvery Water Disputes Tribunal (CWDT) award and the Supreme Court’s 2018 judgment.
As per official documents available with TNIE, the CWC had returned the DPR to Karnataka on June 29 for suitable alterations as the state had proposed to expand the volume of water that could be stored for consumptive use by 2.2 tmcft.
The upper riparian state had also introduced a completely new component, the Shivanasamudra Run-of-River Power Project, involving construction of a diversion weir across Cauvery, in the revised project report.
The CWC’s observations came after it examined a compliance report submitted by Karnataka on April 21, 2026, in response to queries raised by the commission on the original DPR submitted in 2019.
When Karnataka first proposed the Mekedatu project in 2018, it was presented as a balancing reservoir intended to divert about 23.75 thousand million cubic feet (tmcft) of water to provide an additional consumptive use of 4.75 tmcft for drinking water supply to Bengaluru and nearby areas. Based on this, the CWC gave an “in-principle” clearance for preparing the DPR in November 2018.
However, in its revised proposal submitted this April, Karnataka had introduced the Shivanasamudra Run-of-River Power Project and increased the proposed consumptive use from 4.75 tmcft to 6.95 tmcft.
The CWC noted that these were major changes that were never part of the original DPR submitted in 2019. The commission also questioned Karnataka’s justification for constructing a reservoir with a live storage capacity of 59.46 tmcft.
‘CWC findings validate TN’s objections to Mekedatu project’
Live storage refers to the amount of water that can actually be stored and used in a reservoir.
Karnataka justified this large storage by saying it needed 13 tmcft to ensure releases to Tamil Nadu during June and July; 10 tmcft to maintain mandatory environmental flows in the river between February and May; 33.15 tmcft to meet Bengaluru’s future drinking water needs; and 3.85 tmcft to account for evaporation losses and sedimentation. Together, these added up to nearly 60 tmcft of storage, the state claimed.
But the CWC found serious flaws in these calculations. The commission noted that Karnataka estimated Bengaluru’s future drinking water requirement at 64 tmcft by 2044. To arrive at this figure, it deducted only 14.52 tmcft, claiming this was the city’s existing water supply.
However, the CWC pointed out that the 14.52 tmcft figure dates back to June 1990, when Karnataka presented its case before the Cauvery Tribunal. More importantly, the SC, in its 2018 judgment, had already assessed Karnataka’s total drinking and domestic water requirement, including for Bengaluru, at 33 tmcft, with Bengaluru alone requiring 24 tmcft.
The commission also observed that Karnataka had not disclosed how much water Bengaluru is actually using today, even though the city has expanded enormously over the past three decades. Because the proposal relied on outdated figures instead of current data and ignored the Supreme Court’s assessment, the CWC concluded that the basis for fixing the reservoir capacity at 59.46 tmcft “does not seem to be appropriate”.
The CWC also objected to Karnataka’s proposal to increase consumptive use to 6.95 tmcft. The SC had allowed Karnataka to use 6.5 tmcft for additional drinking water needs. But the CWC clarified that this 6.5 tmcft already includes the state’s existing consumption. It noted that even if Karnataka’s 1990 drinking water consumption of 2.9 tmcft is considered, only about 3.6 tmcft remains available for additional use.
Seeking 6.95 tmcft, therefore, exceeds what the SC permitted, the commission said. In view of these observations, the CWC has formally returned Karnataka’s 2019 DPR and directed the state to prepare and submit a fresh DPR in accordance with the CWDT award, the SC judgment and CWC’s appraisal guidelines.
The revised proposal must contain updated technical details, fresh data and revised drawings before it can be considered further. A senior TN Water Resources Department (WRD) official said the CWC’s findings independently validate the state’s long-standing objections to the project.
“Mekedatu project was an attempt to impound nearly 80 tmcft of runoff generated in the intermediate catchment downstream of KRS and Kabini reservoirs, which forms part of TN’s allocated share. The state had maintained that the drinking water justification was merely a pretext to create additional upstream storage,” the official said.
G Sundarrajan, coordinator of Poovulagin Nanbargal, said Mekedatu is “a ploy to appropriate maximum quantity of water” in violation of the Cauvery Tribunal Award, SC judgments and the Cauvery Water Management Scheme. “Chief Minister C Joseph Vijay should not engage in a dialogue with Karnataka CM D K Shivakumar at this juncture,” he said.
CM Vijay declines DKS invitation to inspect catchment areas
CM C Joseph Vijay has declined Karnataka CM DK Shivakumar’s invitation to inspect the Cauvery catchment areas in the state by helicopter, sources said. Vijay will meet his Karnataka counterpart at the latter’s office in Vidhana Soudha complex in Bengaluru on August 3 to discuss the release of Cauvery water and return to Chennai. Chief Secretary M Sai Kumar will accompany the CM.