Mullaperiyar dam unsafe during floods, says study

A study conducted by experts of the Indian Institute of Technology, Delhi, has concluded that the Mullaperiyar dam bordering Kerala and Tamil Nadu is 'hydrologically unsafe' for an estimated probable maximum flood (PMF) of 2.91 lakh cubic feet per second (cusecs) even when the water level is maintained at 136 feet and all 13 shutters are opened.In such an event, the maximum water level will reach 158.67 feet and this will flood the area between the reservoir and the Idukki dam affecting lakhs of people living on the riverbanks.IIT professors Dr. A.K. Gosain and Dr. Subhash Chander, who prepared the report on behalf of the Kerala government with independent data, have said the estimated two-day maximum probable precipitation (rainfall) in the Mullaperiyar catchments is 65.43 cm, and if it occurs, then a PMF of 2.91 lakh cusecs will occur in the catchments and 13.86 tmcft of water will rush to the reservoir within 70 hours.

Baby dam

Kerala Water Resources Minister N.K. Premachandran, who released the report , said the only solution to the problem was to construct a baby dam near the reservoir with the consent of the Supreme Court. The State need not require permission from its Tamil Nadu counterpart for this.According to the Periyar lease deed, valid for 999 years, the maximum water level is fixed at 155 feet and if it exceeds that it would be a clear violation of the lease deed. "Therefore, the demand of Kerala to have a new dam is genuine and logical," he added.The Minister, who disputed the Central Water Commission (CWC) findings on PMF, warned that any compromise on the estimation of PMF would prove disastrous. He said the CWC's recommendation and the Supreme Court's observation that the maximum water level could be increased to 142 feet from 136 feet was unacceptable to Kerala. It is necessary to have a proper estimation of PMF and its effects on the dam's safety.Dr. Subash Chander, who was present, said another solution to the problem was to increase the capacity of the spillways and have an excellent weather forecasting system to alert the people in advance.

The Hindu, July 2, 2008

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