The Cauvery verdict: key questions answered

River Cauvery, the lifeline of the delta districts in Tamil Nadu.   | Photo Credit: E. Lakshmi Narayanan

The Supreme court in its verdict on Friday tweaked the award that the Cauvery Water Disputes Tribunal made in 2007 and also made some key observations on the path ahead for the riparian States.

How will the water be distributed among the States?

 KeralaKarnatakaTamil NaduPuducherryTotal
Irrigation requirement27.90250.62390.856.35675.72
Domestic & industrial water requirement projected for 20110.351.852.730.275.20
Water requirement for environmental protection    10.00
Inevitable escapages into sea    4.00
Share in balance water1.5117.6425.710.2245.08


*740 TMC includes 14 tmc for environmental protection and escapages into sea

How will the reduction in allocation of water affect Tamil Nadu?

This reduction will have a marginal impact on Tamil Nadu because the quantum of reduction is small. It is less than 10% of the 192 tmcft that it ought to receive from Karnataka at Billigundlu every year, as per the Tribunal's award.

The Cauvery Water Disputes Tribunal did not take into account groundwater availability, while apportioning Cauvery water for basin States in its final order. But, the Supreme Court has considered it, saying “The State will have to now bank on 10 tmcft of groundwater available with it.”

This places increased responsibility on Tamil Nadu to protect its groundwater reserves by taking adequate measures.

Another important point to be noted is that Tamil Nadu requires more water (nearly 130 tmcft) during June-September than in other months. That period marks the south-west monsoon, when Tamil Nadu gets less rainfall as compared to the rest of the country.

This is where the role of the CMB comes in.

What is the CMB and why is it important?

The Cauvery Water Disputes Tribunal had prescribed the setting up of a Cauvery Management Board (CMB) and the Cauvery Water Regulation Committee (CWRC) to monitor the implementation of its order.

The CMB would monitor the storage position in the Cauvery basin and the trend of rainfall, to assess the likely inflows for distribution among the States. The CWRC will ensure the Tribunal's order is carried out in due spirit.

The CMB will have three full-time members including a chairman. It will also consist of six part-time members, four of whom will be from the riparian States of Karnataka, Kerala, Tamil Nadu, and the Union Territory of Puducherry.

Once the Board and the Committee are set-up, Karnataka will lose its supervisory control over the four Cauvery basin reservoirs — the Krishnarajasagar , Hemavathi, Kabini and the Harangi reservoirs.

In other words, Karnataka cannot exercise the option to release water to Tamil Nadu only after it had a sufficient storage in the reservoirs, particularly in the years of distress.

How does the verdict benefit Bengaluru?

The verdict should come as much-needed relief for the people of Bengaluru, with the city now entitled to an additional 4.75 tmcft of Cauvery water.

The need for this increase in water share arose as the Tribunal had, in 2007, miscalculated Bengaluru’s water needs. The Tribunal had accounted for Cauvery water use only by the third of the city that falls within the Cauvery basin, while two-thirds is outside the basin. Also, it had assumed that 50 per cent of the drinking water requirements would be met by ground water.

The allocation of 8.75 tmcft to the city proved to be insufficient. The majority of its residents had to make do with groundwater, which due to increasing urbanisation has been depleting and getting more contaminated.

The SC has now said that the assumption that 50% of water demand will be met by ground water is unacceptable. It also debunked the idea of taking into consideration only one third of the city that falls within the Cauvery basin, saying “principles of apportionment and the conception of reasonable and equitable share perceived for such uses comprehend a basin State addressing the social and economic needs of its community as a whole”.

What was the Cauvery Water Disputes Tribunal’s recommendation?

The Cauvery Water Disputes Tribunal gave its verdict on February 5, 2007, 17 years after it was set up.

The Tribunal, comprising chairman Justice N.P. Singh and members N.S. Rao and Sudhir Narain, unanimously determined the total availability of water in the Cauvery basin at 740 thousand million cubic feet (tmcft) at the Lower Coleroon Anicut site on the basis of 50% dependability.

It allocated 419 tmcft of water for Tamil Nadu, 270 tmcft for Karnataka, 30 tmcft for Kerala and 7 tmcft for Puducherry. It reserved 10 tmcft for environment protection and 4 tmcft for inevitable "escapages" into the sea.

The Tribunal said the use of underground water by any of the riparian States should not be reckoned as use of Cauvery water. The Supreme Court, however, took into account the quantity of available groundwater while calculating the final determination of the share.

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Printable version | Jul 30, 2021 6:16:14 AM |

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