Mullaperiyar Dam Dispute: History, deadlock, and what’s at stake

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admin November 5, 2021
Updated 2021/11/05 at 2:18 PM

The Supreme Court last week heard a public interest litigation case brought by a Kerala physician and two former local body members on the functioning of the Mullaperiyar dam, which Kerala and Tamil Nadu have been warring over for a long time. With floods impending and reservoirs swelling, the court ordered both states to follow the rule curve for the time period defined by the Supervisory Committee formed at its request. As a result, the dam’s water level will be restricted to 138 feet until October 31 and 139.5 feet until November 10. On November 11, the court will hear the matter once again.

What is the current state of affairs?

On October 30, three dam shutters were opened to discharge water. While those living downstream were evacuated ahead of time, the discharge of water from the Mullaperiyar dam had little effect on the level of the much larger Idukki reservoir, which was at over 94 percent of its storage capacity 35 kilometres downstream.

Why is Mullaperiyar Dam such a thorn in the side?

On October 29, 1886, the Maharaja of Travancore signed a 999-year lease deal with the British government for the building of the Mullaperiyar dam across the Periyar in what is now the Idukki region. The dam was completed nine years later. Farmers in the Theni, Dindigul, Madurai, Sivaganga, and Ramanathapuram districts would benefit greatly from the water provided by a tunnel to the water-scarce southern portion of Tamil Nadu, particularly the Vaigai basin. On average, 22 million cubic feet (tmc ft) of water is diverted, irrigating around 2.20 lakh acres and satisfying the region’s drinking water needs. Concerns about the gravity dam’s safety, which was constructed using lime-surkhi (burnt brick powder) mortar, arose in 1979. In November of that year, a tripartite conference headed by K.C. Thomas, then-chairman of the Central Water Commission (CWC), agreed that the level needed to be reduced from 152 feet to 136 feet to allow Tamil Nadu, which owns and manages the reservoir, to complete dam strengthening work. By the mid-1990s, Tamil Nadu has begun to demand that the level be restored.

What occurred in the court of law?

In 2000, the Central Government formed an expert group to investigate the dam’s safety. The group suggested that the level be raised to 142 feet, which the Supreme Court agreed to in February 2006. By amending the Kerala Irrigation and Water Conservation Act, Kerala tried to limit the level to 136 feet, forcing the Tamil Nadu government to file a petition with the Supreme Court. In February 2010, the court established an authorised committee to investigate the dam’s whole range of challenges. The court ruled down Kerala’s Act in May 2014, allowing Tamil Nadu to keep the elevation at 142 feet, based on the committee’s findings that the dam was “structurally and hydrologically safe.” It also requested that the Central Government form a three-person Supervisory Committee to oversee dam safety.

What makes it a societal problem?

A study commissioned by the Kerala government in the late 2000s by IIT-Roorkee revealed concerns regarding the dam’s survivability in the case of a large earthquake. The dam is situated in seismic zone 3. In 2011, a series of earthquakes in the region aroused concern. Following that, the 2018 floods and the irregular nature of yearly monsoons have refocused attention on the 126-year-old dam.

Why is the case again in front of the Supreme Court?

Joe Joseph, a doctor who ran for the corporate-backed Twenty20 party in the recent Kerala Assembly election from Kothamangalam, downstream of the Mullaperiyar and Idukki dams, filed a complaint with the court last year, along with two others, alleging that the Supervisory Committee had abdicated its responsibilities to a sub-committee formed at the court’s direction for water management in the dam. They also asked the court to request that the CWC adjust the dam’s “rule curve,” “instrumentation system,” and “gate operating timetable.” Massive landslides had wreaked havoc on central Kerala’s hilly regions, and the weather forecast was bleak when the court’s attention was drawn to a report prepared by the United Nations University-Institute for Water, Environment, and Health, which cited “significant structural flaws” in the dam and warned that it “may be at risk of failure.” “Leaks and leaching are particularly worrying,” it noted, “since the procedures and materials utilised during construction are deemed archaic in comparison to contemporary building requirements.”

The Kerala Government, as a respondent, contended that the whole reservoir level should be lowered to 139 feet since the dam was decaying. In the event of a dam breakdown, unspeakable human tragedy would ensue, hence the group proposed decommissioning the dam and replacing it with a new dam to meet Tamil Nadu’s water demands. Apart from rejecting the notion of a new dam, Tamil Nadu has been fighting any proposal for decreasing the level from 142 feet, citing two Supreme Court judgements. It claims it’s working to finish the remaining dam-strengthening projects, including those for the ‘baby dam,’ which sits beside the main dam and requires approval from the Kerala and federal governments.

So, what’s on the horizon?

Kerala’s Irrigation Design and Research Board is nearing completion on the design of a new dam. However, without Tamil Nadu’s participation, this would not be possible. Meanwhile, with inclement weather anticipated, Kerala Chief Minister Pinarayi Vijayan wrote to his Tamil Nadu counterpart M.K. Stalin, requesting him to drain the greatest amount of water from the dam via the tunnel in order to avert a large-scale discharge. Mr. Stalin assured Mr. Vijayan of his full support, saying that the dam’s level was being continuously monitored and that the present storage was well within the Supreme Court’s permissible limits. In December, a conference of Chief Ministers will be held to debate the problem.

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