In a setback to Tamil Nadu, the Supreme Court on Friday reduced its share of the Cauvery river water to 177.25 thousand million cubic feet (TMC), down from 192 TMC allocated by a Tribunal in 2007.
A bench of Chief Justice Dipak Misra, Justice Amitava Roy and Justice A.M. Khanwilkar reduced the share of the state as it noted that the Cauvery Tribunal had not taken into account the 20 TMC of ground water available in Tamil Nadu's side of the river basin.
"In totality, we deem it appropriate to award to the State of Karnataka an additional 14.75 TMC of water, i.e., 10 TMC (on account of availability of ground water in Tamil Nadu) + 4.75 TMC (for drinking and domestic purposes including such need for the whole city of Bengaluru)," the court said in its order.
In view of the allocation of an additional 14.75 TMC of water to Karnataka, the court said: "The State of Karnataka would now be required to release 177.25 TMC of water at the inter-state border with Tamil Nadu, i.e., at Billigundulu."
Justifying the cut in the share of Tamil Nadu, the court pointed to the empirical data which suggested that around 20 TMC of groundwater was available in Tamil Nadu -- a position which the Tribunal did not take into account describing it as a "conjecture".
"We, while keeping in mind the risks associated with over-extraction of underground water, deem it fit that 10 TMC of the said available groundwater in Tamil Nadu can, in the facts and circumstances of the present case, be accounted for in the final determination of its share", the court said.
Therefore, the share of Karnataka has been increased by 14.75 TMC, which includes increased allocation for "global" city of Bengaluru for drinking purposes.
"Drinking water requirement of the overall population of all the States has to be placed on a higher pedestal as we treat it as a hierarchically fundamental principle of equitable distribution," said Chief Justice Dipak Misra speaking for the bench.
Allocating 4.75 TMC to Bengaluru, the judgment said that Karnataka could use the increased allocation for irrigation and industrial purposes by marginally increasing its area under crop.
"Keeping in mind the global status that the city (Bengaluru) has attained, an addition of 4.75 TMC is awarded to Karnataka," the court said.
The court hiked the allocation of water for Bengaluru as it found "unsustainable" the Tribunal drastically reducing Karnataka's share towards domestic and industrial purposes for the reason that only 1/3rd of Bengaluru falls within the river basin and also on the presumption that 50 per cent of the drinking water requirement would be met from ground water supply.
While bringing down the allocation for Tamil Nadu, the top court kept intact the allocation made to Kerala and Puducherry by the Tribunal.
The court directed that as per the Tribunal award, the Centre would take steps for setting up the Cauvery Water Management Board for the implementation of the interim water sharing arrangement, which it said would remain in operation for the next 15 years.
Concurring with the Tribunal awards, except for the reduction in the share of Tamil Nadu, the court said that after considering all relevant material brought on record, "we are of the view that having regard to imperative of economy of consumption of water, the final determination of irrigated area arrived at by the Tribunal for Tamil Nadu cannot be declared incorrect or fallacious".
Referring to its answer to the Presidential reference on the Cauvery Water Dispute Tribunal, the court said that "waters of an inter-state river passing through corridors of the riparian states constitute a national asset and no single State can claim exclusive ownership of its water".