Kerala is once again on the edge and social media is rife with concerns over the 126-year-old dam across the River Periyar at Mullaperiyar. The coming days are likely to be a repeat of the series of incidents that Tamil Nadu and Kerala had witnessed a decade ago when social media went on an overdrive regarding the safety of the structure.
The two neighbouring states, meanwhile, are busy revisiting the studies and reports on the strength and safety of the more-than-a-century-old structure. The political leaderships are treading cautiously since the issue affected the population of both the states.
But, is there any basis for the concerns that are being posted and forwarded on social media? To answer the question, one should travel 126 years back.
The dam at a glance
Originating from Chokkampatti in Tamil Nadu's Sivagiri Malai (hill), the River Periyar flows 48 kilometres west to join Mullayar to become Mullaperiyar. The disputed structure was commissioned on October 10, 1895, at Vallakkadavu in Idukki district's Peermade taluk.
The dam was constructed to keep alive Madurai's lifeline, the River Vaigai, during the six months, which otherwise would remain dried up for half of the year.
Discussions regarding constructing a dam began in 1789, and British engineers Colonel John Pennycuick and R Smith submitted a blueprint in 1882. Two years later, the British started a dialogue with King Visakham Thirunal of Travancore. Following the talks, Travancore signed a deal with the Government of Madras in 1886.
The construction, which started in 1887, used soorki, a mixture of lime, jaggery, sugarcane juice, egg-white and others, and granite, to lay the foundation of the now-disputed structure.
The structure comprises the 152-foot high and 1,200-foot long main dam, a baby dam of 240 ft x 115 ft, and an earth dam of 240-foot long and 20-foot width. Initially, 42 square kilometres of forest land was submerged as the dam held 152 ft of water. Kerala, however, rarely gets water from the reservoir.
The dam, under the control of Tamil Nadu, diverts the river, formed by streams from five hills, Chokkampatti, Sivagiri Malai, Plachimala, Nagamala and Madalamthookkimala.
Mullathodu originates from Vellimala, and the original plan was to construct a dam across it at Kallidichal. However, Pennycuick felt more water could be stored if the dam was constructed across the Periyar.
The far-sightedness of John Pennycuick to address droughts in five Tamil Nadu districts made Mullaperiyar possible. The Tamil Nadu government has declared January 15, the birthday of Pennycuick, as a public holiday from this year. The Madras famine during the fag end of the 18th century led Pennycuick to the Travancore king with a plan to construct a dam across the River Periyar.
The construction began with funds allocated by the Madras Province, but the partially constructed structure was washed away in torrential rains. When it repeated once again, the Madras government dropped the plan, but Pennycuick sold off his and wife Grace Georgina's properties to raise funds and successfully complete the construction.
The success made him the Secretary of Public Works in Madras Province. He left for England in 1903, where he lived in a government-provided accommodation till his death on March 9, 1911, at the age of 70.
New dam remains a dream
Post-independence, the water level was increased to over 152 ft, and in 1948, Tamil Nadu decided to use the water from the irrigation project to generate electricity.
Construction of the powerhouse commenced in 1952, and it started generating power in 1958.
Meanwhile, the dam overflowed in 1961, and Tamil Nadu took up grouting works in 1965 and 1973 to strengthen the structure.
Tamil Nadu and Kerala renewed the agreement on May 29, 1970. The water level was brought down to 136 ft after the structure was found to be weak. It was then decided to strengthen the dam temporarily till a new structure is constructed. Tamil Nadu, which later found that the new dam would be outside its leased revenue land, put the plan on the backburner. Kerala, on its part, ignored the plan, which has now led to heightened concerns over the dam, besides giving nightmares to the riparian population.
The Thekkady Lake
The Thekkady Lake was formed after the construction of the Mullaperiyar dam. Tamil Nadu takes water from the lake through a two-kilometre tunnel to Kulangal and Vaigai dams, from where it is used for irrigation purposes and providing drinking water to Theni, Madurai, Dindigul, Ramnadu and Sivagangai districts, besides generating power.
A supplementary agreement was signed with Tamil Nadu when C Achutha Menon was the Chief Minister of Kerala. The deal allowed Tamil Nadu to generate power using water from Mullaperiyar. Leaks found in the structure in 1979 triggered the dispute over the water level. A five-judge Constitutional Bench of the Supreme Bench ordered the water level to 142 ft on May 7, 2014.
Following the controversy over the safety of the dam, the Central Water Commission visited the structure and instructed to lower the water level to 136 ft from 152 ft. The commission also identified a site for the new dam. Tamil Nadu, which took up works to strengthen the existing structure, ignored the proposal for a new dam.
The issue reached the Supreme Court again after questions were raised over the safety of the dam. The apex court constituted a five-member committee under Justice AS Anand to study issues pertaining to Mullaperiyar in February 2011. Based on the committee's report, Tamil Nadu received the nod for raising the water level to 142 ft from 136 ft. The water level exceeded 142 ft on August 15, 2018.
A three-member supervisory committee, with the representative of the Central Water Commission as its chairperson, was formed based on the recommendation of the Justice Anand commission. Representatives of Kerala and Tamil Nadu formed the remaining members of the panel. A five-member sub-committee was also formed to assist the supervisory panel. The sub-committee has been mandated with the task of submitting a quarterly report after visiting the dam. However, Tamil Nadu has not been cooperating with the panel, which often forces the panel to drop its inspection plan.
No advance warning
The spillway of the Mullaperiyar dam has 13 shutters. When the shutters are opened, water will flow to the Idukki reservoir via Vallakkadavu, Vandiperiyar, Mlamala, Chappath, Upputhara and Ayyappankoil. Since Tamil Nadu opens the shutters to release water without warning, those on the banks of Periyar live in perpetual fear of floods. People still recall Tamil Nadu releasing the waters without issuing any warning on the night of August 14, 2018.
The inflow into Mullaperiyar now is 1,209 cubic feet per second (CFS), while the outflow, as of October 20, is 1,750 CFS. Concerns have been raised over the possibility of the water level shooting to 142 ft when more rainfall adds to the inflow. Hence, Kerala has demanded Tamil Nadu to release water through the tunnel.
The floods of October 16 have left a trail of destruction in Kerala. Kerala alerted Tamil Nadu when the water level at Mullaperiyar reached 133.45 ft on October 18. Three shutters of the Cheruthoni dam were raised after releasing water from the downstream Idamalayar dam.
Tamil Nadu notified on Saturday evening that the water level of Mullaperiyar has reached 136 ft. The second notification will be issued once the water level touches 138 ft, and the first alert will be issued at 140 ft. The maximum sanctioned capacity of the reservoir is 142 ft, and water will be released only after it reaches that level.
It is yet to be known if the chief ministers of Tamil Nadu and Kerala will arrive at a consensus before the water level touches 142 ft. Chief Minister Pinarayi Vijayan has already written to his Tamil Nadu counterpart on this issue.
Tamil Nadu is expecting to retain the water level below 136 ft since the intensity of rainfall has waned. However, their calculation may go wrong if the northeast monsoon brings in copious amounts of rain.
The Mullaperiyar water level has touched the 142 ft mark three times after the Supreme Court had allowed it to raise the level. If the water level touched 142 ft on November 21, 2014, and December 6, 2016, it went past the mark on August 15, 2018. It has been noted that the water level increases to 142 ft during the retreating monsoon.
The first northeast monsoon shower of this year was received on Tuesday. It is in this backdrop that several people, including celebrities, demanded the decommissioning of the Mullaperiyar dam.