The case for a new Mullaperiyar dam

The existing dam is unsafe. There is ample scope for Kerala to invoke the ‘precautionary principle of action' in order to protect its people.

Updated - July 29, 2016 05:42 pm IST

Published - January 03, 2012 01:13 am IST

Kerala’s apprehensions about the 116-year-old Mullaperiyar dam’s stability are not of recent origin. File photo: H. Vibhu

Kerala’s apprehensions about the 116-year-old Mullaperiyar dam’s stability are not of recent origin. File photo: H. Vibhu

In his article headlined “Unwarranted fears on Mullaperiyar,” published in The Hindu on December 31, 2011, Durai Murugan, Tamil Nadu's former Minister for Water Resources and Law, and senior DMK leader, attempts to portray Tamil Nadu as a potential victim of machinations by Kerala aimed at depriving Tamil Nadu of its rightful share of water from the Mullaperiyar dam. It is necessary to lay out the facts relating to the stance taken by Kerala so as to impart greater clarity on, and understanding of, the issue.

It is true that the Mullaperiyar dam was commissioned as part of a lease deed signed in 1886 to divert the waters of the Periyar for irrigation in parts of the Madras Presidency, and that Tamil Nadu is entitled to claim its share as a right. But by no stretch of imagination can the Periyar be classified as an inter-State river, as claimed in the article. The river across which the dam is situated is entirely in Kerala; no part of it originates from, or runs through, any other State. The entire stretch flows through Kerala, with a negligible 2 per cent contribution from insignificant rivulets from Tamil Nadu joining the main course downstream of the Mullaperiyar dam. Therefore, claiming that Mullaperiyar is an “inter-State resource governed by the principles of inter-State rivers” is fallacious.

Kerala has not repudiated the Periyar lease agreement at any point: this is indeed a reflection of the earnest desire on the part of Kerala to assure its brethren across the border that it would not renege on its assurance to ensure water to Tamil Nadu. The issue of the validity of the original lease agreement is pending before the Supreme Court, with a Constitution Bench examining the merits of this pre-Independence-era agreement.

The author seeks to assert that “the land belongs to Tamil Nadu.” This is a new claim, fraught with serious ramifications. Tamil Nadu is merely the lessee. Far from helping to find a lasting solution within the federal framework, this new contention will only serve to provide a new twist to the imbroglio.

Kerala's apprehensions about the dam's stability — or lack of it — are not of recent origin. It was built when construction techniques were in a nascent stage. Its core was built of lime surki concrete, with a facing of coarse rubble masonry in lime mortar. Attempts were made in the 1930s to strengthen it by grouting and guniting. Even after repeating the grouting in 1960, leaks were observed. Tamil Nadu itself has conceded before the Supreme Court that over 3,500 tonnes of lime has been washed away from the structure over the last century. As against this, a mere 542 tonnes of concrete has been put into the dam which, it should be reiterated, relies on gravity for stability. Strengthening cannot guarantee the structural stability of the dam, which lies in a highly seismic zone. That it is necessary to periodically strengthen the dam is in itself a pointer to its intrinsic structural weakness and the hazards that have manifested over time.

Even as the Central Water Commission (CWC) was advocating short, medium and long-term measures to strengthen the dam, Kerala and Tamil Nadu agreed in 1979 that a permanent solution lay in constructing a new dam. At the discussions held on January 25, 1979, under the chairmanship of K.C. Thomas, CWC Chairman, it was decided that “a joint team of engineers from Tamil Nadu and Kerala will explore the possibility of locating a new dam within a reasonable distance from the existing dam.” Officials from both States jointly identified and confirmed the specific location and alignment where the new construction was to be made. Officials from Kerala and Tamil Nadu even inked an agreement on December 20, 1979, to this effect, and this was approved by the CWC Chairman. But this agreement was not carried forward to its logical conclusion. Why is Tamil Nadu objecting to a new dam now?

Kerala has always respected the judiciary and unflinchingly abided by its verdicts. The Supreme Court, in its judgment of February 27, 2006, allowed the raising of the water level to 142 feet, and thereafter to 152 feet upon the baby dam being strengthened. This verdict was based entirely on the recommendations of an Expert Committee constituted by the CWC, which had concluded that the dam is safe, on the basis of erroneous values and insufficient data.

In March 2006, the Kerala Assembly amended the Kerala Irrigation and Water Conservation Act, 2003, fixing the full reservoir level (FRL) of 22 dams in the State. In the case of the Mullaperiyar dam, the FRL was fixed at 136 feet. Through an Original Suit before the Supreme Court, pending final verdict, Tamil Nadu has questioned the Kerala Legislature's competence to enact such an amendment.

The Supreme Court has so far not stayed the legislation fixing the water level at 136 feet, and has only ordered that no dam-strengthening measures be taken up, and that the status quo be maintained on the water level issue. Kerala has the right to object to any cosmetic strengthening measures proposed by Tamil Nadu in the interregnum. It is not true that Kerala has displayed scant regard for a judgment of the Supreme Court.

A study on the “Probable Maximum Flood Estimation and Flood Routing of Mullaperiyar Dam,” by Dr. A.K. Gosain of the Indian Institute of Technology, Delhi, concluded that the dam is hydrologically unsafe. At no point have the findings been disputed. A study on the “Structural Stability of Mullaperiyar Dam with regard to Seismic Effect,” by a team with Dr. Arun Bapat as Chairman, and Dr. D.K. Paul, Head of the Earthquake Engineering Department of the Indian Institute of Technology, Roorkee, as member, predicted that the structure would collapse in the event of a Magnitude-6 earthquake.

These studies point to the fact that the dam is a disaster waiting to happen. In the past few months, the area proximate to the dam has experienced over two dozen tremors of varying magnitudes. The argument that the Idukki dam also lies in this zone and is equally vulnerable is again ingenuous. The Idukki dam has been designed and built to withstand earthquakes of Magnitude-8.

The claim that the Idukki dam can contain the flood water in the event of the Mullaperiyar dam collapsing is contrary to the truth. The combined storage of the Mullaperiyar and Idukki reservoirs had crossed the FRL in 1981, 1992, 1994, 1998, 2005 and 2007. In the event of such a situation arising again and the Mullaperiyar dam collapsing, Idukki would overflow, thereby putting its stability under serious jeopardy. There are more than 1.5 lakh people living downstream between the Mullaperiyar structure and the Idukki dam. What happens to them in the event of damage to the Mullaperiyar dam? Kerala stares at the prospect of a 30-feet tall column of water surging down at a speed of 50 kmph upon the Idukki and Kulamavu dams, thereby overwhelming them and setting off a chain of events that have the makings of an apocalypse for the 35 lakh people living in four districts. The Government of Kerala has to protect its people. There is ample scope to invoke the “precautionary principle of action” in this case, and Kerala is duty-bound to raise it.

It is against this background that Kerala decided to construct a dam downstream of the existing dam to ensure the safety of its citizens and ensure continued supply of water to Tamil Nadu. Contrary to Mr. Durai Murugan's contention, the dam is proposed to be built leaving the present dam intact and without disrupting water supply to Tamil Nadu. It is only on completion of the structure that the old dam is to be decommissioned. Problems pertaining to environmental clearances have been cited in the article as an impediment to the construction of a new dam. The environmental catastrophe that would be unleashed by the collapse of the Mullaperiyar dam, not to mention the cost in terms of human lives lost, needs to be factored in at that stage.

Kerala's commitment to supply the same quantum of water to Tamil Nadu has been endorsed by the Kerala Assembly through a unanimous resolution. Therefore, it is hard to fathom Tamil Nadu's objections against Kerala building a dam on its territory, across a State-river with its own funds. Moreover, is the Tamil Nadu Government — or indeed Mr. Durai Murugan — willing to guarantee that the present structure would withstand the shortcomings in its construction technology and the ravages of nature for the 863 years of the residual period of the lease agreement?

Mr. Durai Murugan contends that there is no scope for further dialogue between the States. Our democracy and the Constitution provide ample opportunity for sustained and purposeful discussions to resolve even the most vexed of issues. Kerala has immense faith in this mechanism to resolve the Mullaperiyar issue to mutual satisfaction. But apparently, Tamil Nadu has been in a state of denial and reluctant to reciprocate, even at the bidding of the Government of India.

The need is for a “new dam,” and not “as good as new dam” as advocated by the Tamil Nadu Chief Minister. In Kerala, we hope the government and the people of Tamil Nadu, and indeed the whole nation, would accept this reality and recognise the need for a dam to replace the existing Mullaperiyar dam.

(The author was Minister for Water Resources in the Left Democratic Front government that preceded the present one in Kerala.)

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