Tamil Nadu ties Cauvery backlog claim to pro-rata share in realised flows

Tamil Nadu has reiterated to the Cauvery Water Management Authority (CWMA) that its demand for clearing a backlog of roughly 16 thousand million cubic feet (tmc ft) in Cauvery water realisation rests on the principle of a pro-rata share in the flows actually received.

The state has stressed that the pro-rata approach carries weight because both the Cauvery Water Disputes Tribunal and the Supreme Court have referred to it for adoption during periods of distress.

In a recent communication to the CWMA and the Cauvery Water Regulation Committee (CWRC), the state government said its claim is not based on projected future flows. It is seeking only its pro-rata share of the flows actually realised up to the date of recovery during the distress period, along with the backlog already accumulated.

After sending that communication, the state filed an application in the Supreme Court last week, seeking a direction to Karnataka to make good the shortfall in Cauvery water realisation between June 1 and September 9. The CWRC and the CWMA are scheduled to take up their deliberations on September 24.

Tamil Nadu has contended that its backlog as on September 7, the day before the last meeting of the two bodies, stood at about 16 tmc ft. It argued that rather than ordering Karnataka to release 6,000 cusecs at Biligundulu for the next 15 days, the authority should have directed the realisation of about 20,370 cusecs, equivalent to roughly 1.76 tmc ft a day, at the inter-state border.

The state has also said that the CWMA's failure to ensure release of the backlog of over 16 tmc ft as on September 23 would seriously prejudice irrigation and affect the entire agricultural operations in Tamil Nadu, with consequences for farmers, their families and the state's agricultural economy.

On storage, the state pointed out that against the normal release of 15,000 to 18,000 cusecs a day from the Mettur dam for irrigation in the Cauvery delta, only 12,000 cusecs was being released. It said the supply had to be sustained for 45 days, requiring the release of around 55 to 60 tmc ft, while the storage available in Mettur as on September 8, after reserving water for drinking, evaporation and environmental needs, was only 40 tmc ft.

As on September 21, Mettur's storage stood at 46.95 tmc ft. After accounting for other requirements, the quantity available for irrigation was effectively 34 tmc ft. Assuming no further addition and a discharge of one tmc ft a day, the current storage would last 34 days.

Turning to the north-east monsoon, the state said the rainfall pattern is erratic, uneven or even deficient and cannot be predicted with certainty at this stage. It argued that it cannot be presumed Tamil Nadu will necessarily derive the anticipated benefit from the monsoon, and that the state's present requirement cannot be deferred on the assumption of future rainfall.