Don't raise water level of Mullaperiyar dam, say experts

KOTTAYAM:    Experts have strongly objected to the demand of Tamil Nadu deputy chief minister O. Paneerselvam to increase the Mullaperiyar dam water. The International Dam Safety Authority (IDSA) gives a lifespan of 70 years for a dam, and the water level should be brought down periodically after that, they point out. The Mullaperiyar dam has completed 122 years. "It is entirely unreasonable to raise the water level as across the globe the accepted practice is the other way round since the quantity of water would increase pressure on the dam manifold, especially in the context of the loss of its cementing material. The fact that this is a gravity dam is a grave concern,"  geologist Dr A.V. George told DC.

"It would make the dam weaker and in case of the occurrence of an earthquake the security of the dam will be again under threat." Studies by the National Centre for Earth Science Studies and the Indian Institute of Technology (IIT) Roorkee, say the dam cannot withstand an earthquake of more than 5.5 on the Ritcher scale especially if the water level is above 125 feet. The earthquake occurred at Adukkam near Erattupetta on 2000 December 29, and January 7 had recorded 5.2 and 4.8.

Following them, geologists shifted the Kerala region from zone 2 to zone 3, where it could go up to 6.5. Moreover, the water leakage from the dam was noticed at two shutters (block 11 and 12) pointing to a further weakened state. Justice K.T. Thomas, Kerala's nominee on the high power committee on the Mullaperiyar, told DC that the water level should not be raised above 136 feet. According to the Supreme Court verdict, it could be increased to 142 feet with immediate effect and 152 feet, (the maximum water level envisaged during its construction) after strengthening the dam, whereas Kerala's position is it should be limited to 136 feet.