They nicknamed it ‘water bomb’, and it is hanging like the sword of Damocles and gifting people with sleepless nights. For many years, the aging Mullaperiyar dam has been a nightmare for people living close to it along the Periyar River. Recent earth tremors that came with loud noises, leaving cracks on the walls of houses, have only increased their fear. They believe the dam will burst if there is an earthquake of high-magnitude, and they will be washed away.

The silent protest fast that the people been staging for the last five years at a makeshift pandal in the Karikulam Chapathu village, a few kilometers away from the dam site, demanding a new dam, got loud recently with a number of political outfits joining them. Cashing in on this situation, various political outfits in both Tamil Nadu and Kerala staged protests, vied each other in fasting and took it into an abusive level, worsening the state of affairs.

The 116-year-old Mullaperiyar dam, the bone of contention between the states of Tamil Nadu and Kerala for several decades, was built across the Periyar River in 1895 with a mixture of lime, surki, rubble masonry and mortar. This was built as per a lease deed for 999 years, executed between the Maharaja of Travancore and the Madras Presidency in 1886 to divert the waters of the Periyar River to the Vaigai Basin in Tamil Nadu for agriculture. A composite gravity dam, the Mullaperiyar is 176 ft high from the foundation and has a length of 1200 ft. Ith as a storage capacity of 15.66 TMC (thousand million cubic feet).

Kerala argues that the dam has outlived its life and threatens the life of nearly 35 lakh people living downstream; they demand the construction of a new dam. Countering this, Tamil Nadu says, after the strengthening measures carried out, the dam is as safe as a new dam and Kerala’s arguments are incorrect.

Seismic Threat
The latest worry of people living near the dam site is the sequence of tremors felt in the region. Pointing at the cracked walls of his neighbor Mathukutti’s newly constructed house at Vallakadavu, 3 km downstream from the dam site, Mathew Thomas says, the recent tremors were strong and came along with a loud noise. “Tremors have become very common here. Most nights, we come out and sit outside the house fearing a collapse,” he says. Vallakkadavu is the first human settlement downstream of the aging dam and the first village likely to be hit in case of a dam burst.

Some experts are of the view that tremors of this magnitude are negligible and unlikely to have any effect on the dam. Says CP Rajendran, geologist at the Indian Institute of Sciences, Bangalore, “Such small tremors at Idukki, won’t have any effect on Mullaperiyar dam. It’s around 60 km away from Mullaperiyar. The argument that this would create leakage in the dam is baseless.” He says no earth tremors have been recorded near the dam or beneath the dam so far. “But inactive faulty zones ( zones that are capable of generating significantly destructive earthquakes) can be found here. We can’t ignore the possibility of mild quakes.” While rubbishing those creating panic among people predicting earthquakes and destruction of the dam, he acknowledges that the dam has to be rebuilt taking into account its aging structure.

Meanwhile, Dr John Mathai, senior scientist with Centre of Earth Sciences Studies, Trivandrum says, “In a short span of time, as many as four events have been recorded. This indicates the formation of a high pressure level. There are faulty zones identified in the region. So an earthquake of high magnitude cannot be ruled out.” The region comes under earthquake-prone Zone 3.

Meanwhile, a study conducted by the Indian Institute of Technology, Delhi, said the dam would collapse if an earthquake with a magnitude of more than 5 on the Richter Scale hits the place within 16 kms of the dam when the reservoir level is 136ft. However, this study has been rubbished by Tamil Nadu. “IIT study is the best example for professional dishonesty and technical fraud. It’s irrelevant,” says Veerappan, State Secretary of Tamil Nadu PWD Senior Engineer’s Association.

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