None of the tremors had any impact on Mullaperiyar dam: Tamil Nadu

Taking into consideration Tamil Nadu's stand that the tremors in Idukki were mild and have had no impact on the Mullaperiyar dam, the Supreme Court-appointed Empowered Committee is seeking a report from the Geological Survey of India on the number of recent earthquakes (and their intensity).

Informed sources told The Hindu that the Prime Minister's Office had forwarded to the committee, the memorandum submitted by Kerala MPs to Prime Minister Manmohan Singh requesting him to persuade Tamil Nadu to accept the State's proposal to construct a new dam and reduce water level to 120 ft. Sources said the PMO was informed that the committee was seized of the issue.

The PMO also sent the letter written by Tamil Nadu Chief Minister Jayalalithaa objecting to the move to constitute a team of experts to formulate a contingency response by the National Disaster Management Authority (NDMA) for Mullaperiyar dam in case it bursts. This issue had also been closed, sources said.

Kerala had said that the 25 earthquakes or tremors in the vicinity of the dam recently had threatened the structure, causing serious concern to the 50 lakh people living downstream.

The Centre for Earth Science Studies had stated that if there was a tremor of magnitude 6 or more, the dam would collapse. The fear was further heightened by the incessant rain in the catchment area, taking the storage level beyond 136 ft.

Kerala pointed out that on November 10, 2009 when the Supreme Court directed Tamil Nadu to maintain status quo, the water level in the dam was 131.8 ft and storage beyond this was a violation of the Supreme Court's status quo order. “Reduction in water level from 136 ft to 120 ft had become absolutely necessary in the light of recent developments,” it said. “The storage could be reduced by diversion through a tunnel by Tamil Nadu and siphoning the water downstream.”

Tamil Nadu had refuted Kerala's stand and reiterated that the dam was safe and that it had been permitted by the Supreme Court to raise the water level up to 142 ft and further to 152 ft, after completing the remaining strengthening measures. “The false propaganda of 22 tremors in the last four months weakening the dam is being made without any basis. In fact, there have been only four tremors in the current year and, in fact, such tremors have been occurring over many years. But, none of them has had any impact on the Mullaperiyar dam as their magnitudes were far below 4.9 and are classified as ‘slight' by the Indian Meteorological Department (IMD).