Need to look out for water sources outside Tamil Nadu to save its ayacut

Though getting published the final award of the Cauvery Water Disputes Tribunal in the gazette of the Union government is a major moral victory for Tamil Nadu, the State cannot rest on its laurels. It has to look for water sources outside Tamil Nadu to save its ayacut of 28 lakh acres, says N. Natarajan, former superintending engineer, PWD, and a member of the Cauvery Family, a group of stakeholders representing different streams of society from the major basin States of Tamil Nadu and Karnataka.

He says that as the Cauvery being a “deficit river,” water problem will continue to haunt the farmers of Tamil Nadu, especially the delta, even if it were to be a normal year and Karnataka were to comply with the award by releasing 192 thousand million cubic feet (tmcft) to Mettur Dam. “What has been prescribed by the tribunal is not sufficient for the ayacut in Tamil Nadu,” Mr. Natarajan contends. The tribunal has specified 419 tmcft for Tamil Nadu, taking the total yield from the Cauvery basin to be 740 tmc ft. While Karnataka has been apportioned 270 tmcft, Kerala would get 30 tmcft and Puducherry seven tmc ft. The 419 tmc ft envisaged for Tamil Nadu includes 192 tmcft to be released from Karnataka and the remainder to be obtained from various rivers, including the Bhavani and the Amaravati and streams and tributaries below Mettur Dam.

Even within 192 tmc ft, seven tmc ft would have to be apportioned to Puducherry and 10 tmc ft is earmarked for environmental needs. There are about 50 drinking water schemes dependent on the Cauvery including the massive ones like that of Ramanathapuram.

“Besides, there would be wastage of four tmc ft which cannot be avoided.”

Thus Tamil Nadu will be left with only 171 tmcft from the award. And the rest — 227 tmc ft — is dependent on the ‘undependable monsoons.’

An author of two books on Cauvery, Mr. Natarajan points out that the thumb rule is that one tmcft can irrigate 6,000 acres. “For Tamil Nadu’s total ayacut of 28.2 lakh acres, the total requirement is 470 tmc ft whereas we won’t have even 400 tmc ft at our disposal. Thus it becomes imperative for the State to look for sources outside the State,” he asserts.

He points out that the National Water Development Agency (NWDA), constituted in July 1982 on the initiative of then Prime Minister Indira Gandhi to study the National Perspective Plan for Water Resources Development of the country, proposed 16 inter-linking canals under Peninsular River Component to provide and divert the surplus water of Mahanadhi to Godavari, and the surplus water of Godavari to Krishna, and through Krishna to Pennar and from Pennar (Somasila Reservoir) to join the Cauvery at Grand Anicut.

Mr. Natarajan argues that the link involving Somasila Reservoir and Grand Anicut is neither technically feasible nor advantageous to Tamil Nadu.


He moots that the alignment of the link from Alamatti dam in Karnataka to Pennar River should be redesigned.

Extending the proposed canal to the Cauvery (Hogenekkal) will be highly advantageous to Karnataka, Andhra Pradesh and Tamil Nadu.

“This canal is technically feasible, economically viable and will be welcomed by all the three States,” he asserts.

This would benefit 1.94 lakh hectares in Karnataka, 1.61 lakh hectares in Andhra Pradesh and 1.2 lakh hectares between Palar and Ponniyar in Tamil Nadu. Besides, the State would be able to realise 105 tmcft, which can benefit about five lakh acres in Salem, Namakkal, Tiruchi, Perambalur, Villupuram and Cuddalore districts.

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