Tamil Nadu asks Supreme Court to order
Tamil Nadu has petitioned the Supreme Court to direct Karnataka to release a backlog of 17.604 tmcft of Cauvery water.
The Tamil Nadu government approached the Supreme Court on Sunday, August 30, 2026. It seeks a directive for Karnataka to release 17.604 tmcft of Cauvery water, a backlog calculated through a pro-rata formula as of August 27.
In a supplementary affidavit settled by senior advocate G. Umapathy and re-settled by C.S. Vaidyanathan, the state also urged the court to order Karnataka to release 9,000 cusecs of water daily between August 26 and September 8. This matches a directive from the Cauvery Water Management Authority (CWMA). Tamil Nadu further requested the court to direct Karnataka to compensate for any shortfall in water flows at the border village of Billigundulu between August 27 and 30.
Farmers severely affected
Tamil Nadu's affidavit, filed by advocate B. Karunakaran, describes severe impacts in the Cauvery Basin. The state argues that farmers in the Cauvery Delta are seriously prejudiced. The Kuruvai season is nearly over. The Mettur reservoir could not open for irrigation due to inadequate storage, severely affecting cultivation of the samba crop. This is causing great anxiety among the farming community, which is not receiving its due share of water even on a pro-rata basis this year.
A Bench headed by Justice Vikram Nath is scheduled to hear the case on August 31. In a previous hearing on August 24, the court advised Tamil Nadu to raise its concerns about proportionate water releases before the Cauvery Water Regulation Committee (CWRC) and the CWMA in meetings scheduled that week.
Tamil Nadu's arguments to water committees
Tamil Nadu stated that its member raised the state's concerns at a CWRC meeting on August 24. The member asserted Tamil Nadu's entitlement to receive around 28 TMC (thousand million cubic feet). The member asked the CWRC to facilitate the release of about 22,000 cusecs (equivalent to 1.9 TMC per day) for 15 days starting August 24.
The state also submitted to the CWRC that Karnataka had already drawn over 20 TMC from its canals for irrigation, including through anicut channels and lift irrigation systems. Tamil Nadu noted it had not yet been able to open the Mettur reservoir for irrigation. However, the CWRC directed Karnataka to ensure releases so that a flow of 9,000 cusecs is realized at Billigundulu from August 25 to September 8.
Tamil Nadu told the court the CWRC fixed this 9,000 cusecs rate for 15 days without considering an accumulated backlog of 17.415 TMC as of August 23.
Backlog and CWMA order
The state raised its grievance about the "gross inadequacy" of the CWRC order at a CWMA meeting the next day, August 25. Tamil Nadu informed the Supreme Court it had urged the CWMA to direct Karnataka to ensure a release of 1.9 TMC per day from August 24 to September 7. This would address the backlog under the pro-rata formula.
According to the affidavit, the CWMA failed to take steps to direct Karnataka to make good the backlog. The state contends the authority mechanically affirmed the CWRC's recommendation and directed Karnataka to ensure only 9,000 cusecs per day from August 25 to September 8, without considering the mandate for pro-rata releases in distress years under the Inter-State Water Disputes Act scheme. The case is set for hearing.
