Why Tamil Nadu and Karnataka are sparring over Cauvery water? | Explained
The story so far: The eight-year-old Cauvery Water Management Authority (CWMA) is holding its 53rd meeting in New Delhi on Wednesday (July 22, 2026) amid
The story so far: The eight-year-old Cauvery Water Management Authority (CWMA) is holding its 53rd meeting in New Delhi on Wednesday (July 22, 2026) amid an extremely poor southwest monsoon (June-September) in many parts of southern States, especially catchment of the Cauvery river. The two principal riparian States — Karnataka and Tamil Nadu — are expected to present their point forcefully at tomorrow’s meeting, as they have been reeling under the impact of an adverse monsoon. How did the CWMA come into being? Established on June 1, 2018, the Authority was constituted as an implementation mechanism for the Supreme Court’s (SC) 2018 judgment and the final award of the Cauvery Water Disputes Tribunal (CWDT) of 2007. The key aspect of the judgment pertains to water allocation among the constituents of the Cauvery basin. Holding on to the total availability of water, 740 thousand million cubic (tmc) feet, in the basin during a normal year, as determined by the CWDT, the Court made the allocation for the constituents as follows: Puducherry (7 tmc ft); Kerala (30 tmc ft); Karnataka (284.75 tmc ft) and Tamil Nadu (404.25 tmc ft). Additionally, 10 tmc ft and 4 tmc ft were set aside for environmental protection and inevitable escapages into the sea. In the case of Karnataka, the Court allocated 4.75 tmc ft specifically to Bengaluru, which, it referred to as having attained “global status,” and the city’s drinking water requirement had risen multifold. Besides, the Court reduced Tamil Nadu’s original share, which was fixed by the Tribunal in the final order at 192 tmc ft, by 10 tmc ft and transferred that quantity to Karnataka. As a result, Karnataka’ share, which was determined by the CWDT as 270 tmc ft, increased by 14.75 tmc ft. One of the salient features of the Court’s verdict pertains to Karnataka’s commitment to Tamil Nadu. The upper riparian State is to ensure, at Biligundulu, located on the inter-State border, 177.25 tmc ft, as per a monthly schedule that is divided into blocks of 10 days each.
Of this quantity, 123.14 tmc ft is to be provided during the period from June to September, also marks the monsoon. Invariably, it is during this period that the Cauvery issue flares up in times of poor rainfall, as has happened now. How is the CWMA functioning? The Authority, headed by a full-time chairman, has two whole-time members dealing with water resources and agriculture. It consists of two part-time members drawn from the Union Ministries of Jal Shakti and Agriculture, apart from representatives of the four constituents of the basin. The Member-Secretary of the Authority is the chief of the Cauvery Water Regulation Committee (CWRC), which assists the CWMA in arriving at decisions. The Committee includes, among others, a representative of the Meteorological Department. The CWRC is required to meet once every ten days in June and October, and after the onset of the southwest and northeast monsoons, the frequency is at least once a fortnight. As for the Authority, there is no specific stipulation, but it invariably meets at the beginning of the water year (June-May) to determine the total residual storage in eight specified reservoirs and order water releases.. It meets as and when required. Ordinarily, the CWMA’s meetings are preceded by meetings of the CWRC. Last week, the Regulation Committee held its deliberations. During the current water year, the Authority met once in June. What is the situation with regard to rainfall in the Cauvery catchment and storage in reservoirs? Between June 1 and July 21, Karnataka, the upper riparian State that has four reservoirs in the basin, experienced a 28% deficit in rainfall, according to a report from the Meteorological Department. The situation in southern interior Karnataka, where the catchment of the Cauvery River lies, is worse, with a deficit of 36%. Kodagu, where the river originates, recorded a deficit of 37%. The plight in Wayanad, Kerala, the catchment area for the Kabini River (one of the tributaries of the Cauvery), is much worse, with a deficit of 61%.
The BriefWire