J. Venkatesan

New Delhi: The Kerala Government on Tuesday filed an affidavit in the Supreme Court strongly opposing Tamil Nadu’s plea for raising the water level in the Mullaperiyar dam from 136 ft to 142 ft.

In its reply to Tamil Nadu’s suit, Kerala enclosed a report of the study conducted by IIT-Delhi, which says “Mullaperiyar dam is hydrologically unsafe {at the impinging level of 136 ft) for passing the estimated probable maximum flood with the existing spillway capacity.”

In its suit, Tamil Nadu had sought a direction to restrain Kerala from implementing the law requiring Tamil Nadu to seek prior permission from Dam Safety Authority set up by Kerala before raising the water level beyond 136 ft.

Kerala appointed IIT-Delhi to assess Probable Maximum Flood (PMF) Estimation and Flood Routing in the dam. PMF is the flood that may be expected from the most severe combination of critical meteorological and hydrological conditions that are reasonably possible in the region. PMF is a flood that can occur but is not likely to be exceeded.

In its report, the team said: “The PMF recommended for Mullaperiyar reservoir is 2, 91,275 cusecs. With an impinging level of 136 ft, the maximum water level (MWL) attained is 160.22 ft; with an impinging level of 142 ft, the MWL attained is 160.43 ft and with an impinging level of 152 ft, the MWL attained is 161.74 ft.” Therefore, it would be unsafe to raise the level beyond 136 ft.

In his affidavit, M.K. Parameswaran Nair, who was a member of the expert committee set up in 2001, said: “The expert committee, while recommending the raising of water level to 142 ft, has not considered the important aspect, viz the MWL. The increase of MWL above 155 ft in the case of an archaic gravity dam is highly dangerous as this will render the dam structurally unsafe, inviting imminent collapse. Also, the rise of MWL above the maximum legally permitted level of 155 ft is a gross violation of the Lease Deed of 1886.

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