The 126-year-old dam that stands between Kerala and Tamil Nadu

Along with her family, Subina lives with the spectre of a water crisis. Her worries, however, aren’t about tap water, but a large, ageing reservoir filled to capacity. One day it will burst and wash their lives away, she fears.

The village of Vandiperiyar is a few kilometres downstream of the Mullaperiyar dam in Idukki. As a marriage migrant, Subina picked up on these fears from her new family and neighbours, for whom discussing court-sanctioned water levels in the dam, its carrying capacity, seepages in its structure, its convoluted litigation and political implications is dinner-table conversation. Subina, who is also studying for her civil service entrance exams, is so incredibly smart and articulate that she’s spoken up about the fears and demands of the locals here on Malayalam TV news debates.

“The water here in our homes is not potable, but we’re not worried about that," Subina told Mint. “We don’t want any of the water from the Mullaperiyar to be given to Kerala. We just want to be able to live here safely and for that, the only solution is to build a new dam."

Decades in dispute

Kerala, where the dam is located, and Tamil Nadu, which controls the flow of the water inside the reservoir, have been locked in a decades-long bitter dispute about the safety of the 126-year-old structure.

Local politicians on both sides keep emotions running high and build resentment, occasionally allowing it to boil over into protests and riots, despite fairly close social and economic relations between the border districts. Idukki hosts a substantial population of Tamil-speaking settlers who labour in its tea and spice plantations while Malayalis often cross over into Tamil Nadu for work and higher education.

Kerala is convinced the dam presents a threat—if it bursts—to not just the population immediately downstream but that a domino effect on neighbouring reservoirs would wipe out millions of lives in districts as far as Kottayam, Ernakulam and Alappuzha. Across state lines in Tamil Nadu, in the rain shadow of the Western Ghats, the water from the Periyar river routed through this dam has been an irrigation lifeline to nearly three lakh hectares of drought-prone agricultural land for over a century that they refuse to gamble with.

This dispute on dam safety, which Tamil Nadu claims is a fallacy, has been argued at both state high courts and the supreme court for 20 years now. While the two state governments continue to face-off in this political brinkmanship, local residents, those reliant on the dam for their livelihoods as well as those who fear for their lives, continue to be wary of each other.

Central Kerala districts have faced successive flash floods, with extensive loss of life and damage to property, from the 2018 to 2021 monsoon seasons. While changes in long-term climate patterns have made adverse weather events more frequent, residents downstream the Mullaperiyar dam are furious with Tamil Nadu for what they experience as a sudden discharge of water from the dam with no early warnings. That worsens the monsoon floods. The fears of a dam-related catastrophe have reached a crescendo in Kerala yet again and the state government has, once more, demanded a safety review at the supreme court.

Who benefits?

James Wilson is a dam safety expert and member of a special advisory group of the Kerala State Electricity Board which owns and operates large hydel projects in the state. Wilson was part of Kerala’s second litigation on the dam, that led to the supreme court appointing a supervisory committee in 2014 to continually monitor the dam’s resilience.

At the heart of the disagreement is the disproportionate benefit to Tamil Nadu from the dam, and the state’s refusal to acknowledge the safety perceptions of those living downstream, Wilson said. “Tamil Nadu generates electricity from the dam as well as all the water while Kerala bears all the risk. So, a sustainable solution is for a new dam to be built with investment from both states and both sharing the electricity the hydel plant generates. Until then, this debate won’t be resolved," he said.

“The committee, with representatives from the two state governments and a senior officer from the Central Water Commission (CWC), only visits the dam twice a year," Wilson added. “Instead, what we need is continuous monitoring of both the water levels and the structural strength of the dam. Safety is a dynamic function here. Ideally, we should create a joint data collection and publication methodology that is transparent and will create confidence among the residents downstream that the dam is safe."

“Buy lifeboats"

The chorus to decommission the dam peaked last year, when a Change.org petition by a Kerala High Court advocate Russel Joy racked up 840,000 online signatures, including from some of Malayalam cinema’s biggest celebrities.

Understandably, Joy is a vocal opponent to the dam’s continued functioning, a view he airs frequently as a guest at political events and on TV interviews. In 2018, he successfully petitioned the supreme court to set up a disaster management panel for the dam. In a recent video for a Malayalam news channel, Joy speaks to his audience from a stationary speedboat, presumably from somewhere along the state’s famed backwaters. Joy opens his 10-minute address explaining why he is in the boat.

“The owner of this boat isn’t here with me today, but I can tell you that he bought this in case the Mullaperiyar dam breaks; the boat will let him escape into open sea quickly," Joy says in Malayalam. “This has become our last resort now, hasn’t it?"

Joy advises his viewers who can afford speedboats to buy them soon, and lifejackets, for everybody else. “Earthquakes are becoming more frequent in Kerala and who knows how many dams here will break," Joy continues. “What we do know is that our governments aren’t prioritising our safety. So, buy a life raft. It costs ₹35,000-40,000 and (when the dams break) you can save six-seven people this way."

Joy has a writ petition pending before the supreme court asking it to appoint an international agency that can judge the remaining lifespan of the dam and fix a date for its decommission. His primary argument is that dams have an average lifespan of about 40 years and are typically decommissioned in other countries after this period. A 126-year-old dam, then, has no hope of continuing to function.

Conflicting positions

He’s not necessarily correct. Mullaperiyar, in fact, is not the only dam that is over 100 years old in India. In the CWC’s national register of large dams, there are several others that are over a century old and still operational.

“Based on our reviews, we have often recommended balance strengthening measures for the dam to be carried out by the Tamil Nadu government," a senior CWC official, who requested anonymity since he is not authorised to speak to the media, told Mint. “Some of these recommendations have been pending since 2006 because even when Tamil Nadu agrees to carry out this work, the Kerala government denies them permission to do so on the ground."

Rather counter-intuitively to its public stance on prioritising safety, Kerala has frequently thwarted efforts by Tamil Nadu to carry out strengthening work on the dam. For instance, last November, it denied permission to Tamil Nadu to cut trees downstream of the baby dam to strengthen it. (The baby dam is one of the four dam structures, which also includes a main dam, earthen dam and spillway). Kerala believes any strengthening work on the dam will weaken its own demand for a new dam; Tamil Nadu hopes that completing the safety recommendations will allow it to argue in favour of raising the recommended reservoir level to its maximum capacity.

Changing climate patterns

Roxy Koll, a senior climate scientist, has studied how monsoon patterns in India have changed since the 1900s. His team at the Indian Institute of Tropical Meteorology, Pune, found that while total annual rainfall from the south west monsoon has reduced overall since the 1950s, short periods (ranging from two-three hours to two-three days) of heavy rainfall have increased, putting India’s rain-fed regions at higher risk simultaneously of both drought as well as cloudbursts and rain-induced flash floods.

“We’ve observed that there is this increase in short-span heavy rainfall events particularly in central Kerala, in the districts of Idukki, Kottayam, Pathanamthitta and Ernakulam," Koll said. “Flash floods and landslides have become more common due to these heavy rains, aggravated by changes in land use patterns, deforestation in favour of monoculture (like Idukki’s tea, rubber and cardamom plantations) and excess quarrying. More than half of the forest cover downstream of where the dam is now has been lost since 1900."

In the short-term, Koll recommends that governments can manage potential disasters better by integrating rain forecasts from the Indian Meteorological Department with better calibrated reservoir management and water discharge systems. This means that several departments at the Centre and both states will have to be ready to respond jointly, and speedily, to manage adverse weather events in the future.

Unsafe practices

The CWC official quoted earlier said that much of this information is already with Kerala. The state, however, is often reluctant to share it with Tamil Nadu. “Kerala has installed some instrumentation to gauge the water inflow upstream at the confluence of the Mullayar and Periyar rivers (the dam is built at their confluence), the inflow into the dam, the rainfall in the catchment area, etc. Kerala needs to make this available to Tamil Nadu on a real-time basis so (the latter) can plan the water discharge better."

With the two states at loggerheads and neither willing to compromise on its position without losing face electorally, the CWC hopes that the new Dam Safety Act, 2021, will force a rapprochement.

While dams have so far been under the respective state’s regulatory control, the law mandates periodic safety audits and balance strengthening work as recommended by the newly constituted national dam safety authority. “Earlier, we could only recommend safety guidelines to states, and not ensure compliance. With this Act, non-compliance becomes a criminal offence," the CWC official said.

On 8 April, the supreme court further empowered the supervisory committee with interim functions and powers equivalent to the National Dam Safety Authority, a new body proposed under the 2021 Act.

Ending hostilities

At Vallakkadavu, a village that is a little over four km downstream from the dam, lives 68-year-old Abu Bakr. He remembers fishing with his friends in the dam waters as a teenager, a time when locals could freely access this neighbourhood reservoir. Today, the dam can no longer be approached from the Kerala side, by local residents, government officials or even politicians.

Back in the ‘90s, Abu Bakr had been hired as labourer by the Tamil Nadu public works department for repair and structural strengthening work at the dam. Of the several Idukki residents Mint interviewed in the villages downstream to the Mullaperiyar, Abu Bakr was one of only two who has ever visited the dam (the other is a retired police constable).

I ask if he’s scared of the dam bursting one night. “Not really," he responds. “I’ve seen the dam; I know it’s strong. But my children are very frightened; they haven’t seen it from the inside and they imagine the worst."

These days, Abu Bakr runs a small roadside shop, built off a ledge below which runs a stream, an insignificant offshoot of the mighty Periyar that the two southern states are battling over. In March, as the summer heat gathers force in Kerala, the stream is bone dry.

“In the monsoon, when the water is released from the dam, we aren’t warned in advance," Abu Bakr said. “We only find out when the roads are flooded and the bridge is submerged, and of course, we’re all angry again. I’m surprised you’re here in the summer. The politicians come during the rain. For the rest of the year, nobody cares."