Chennai: Life came to a standstill in many parts of Chennai that remained submerged for over four days last week, after the city witnessed its most intense spell of rain in 47 years — 40 cm within 44 hours.
According to official figures, 20 lives were lost in rain-related incidents in the aftermath of Cyclone Michaung, compared to the more than 200 lives lost in November-December 2015.
Though parts of Chennai, prone to high rainfall, flood every year, experts say larger issues such as city planning need to be addressed, adding that unfettered growth and encroachments around lakes and marshlands have destroyed the city’s natural wetlands.
For instance, Cyclone Mandous caused severe waterlogging last year in Ambattur and Perambur, among other areas. The year before that, in 2021, inundation was reported from nearly 200 spots across the city, including Madipakkam, Kovilambakkam and Vellachery from where residents had to be rescued in boats by the state disaster relief authorities.
“Chennai is a completely unplanned city which has grown from small villages with lush green farms and lakes and fishing hamlets 500 to 600 years back into what we see now,” says G. Sundarrajan, an environmentalist associated with the Poovulagin Nanbargal (Friends of the Earth), a Tamil Nadu-based environmental organisation.
Chennai, he adds, became a city “only by destroying and encroaching water bodies and farmlands”.
Meanwhile, Greater Chennai Corporation Commissioner Dr J. Radhakrishnan tells ThePrint that the flooding last week was the result of a “double whammy” of heavy northeast and southwest monsoons. The civic body, he adds, is constantly desilting water bodies and improving their holding capacity, besides taking action against encroachments.
According to him, the biggest challenge for Chennai is that the city is a mere 6.7 m above sea level. The gradient or natural slope of the Chennai landscape, from west to east, is about 6-2 m and surface runoff escapes only through three river mouths and the Buckingham canal.
Environmentalists, however, say there have been instances of government entities encroaching the banks of these water bodies, and of land usage for sensitive areas being changed to industrial or residential.
“Mismanagement of water bodies and rampant encroachment by the administration where land (on riverbanks) is converted to industrial or residential land, is why the city is now facing this crisis,” says Jayaram Venkatesan, convenor of Arappor Iyakkam, an anti-corruption NGO.
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Chennai’s wetlands & water bodies
Chennai, with a population density of 26,902 per sq m (according to the 2011 census) is blessed with three rivers: Kosasthalaiyar, Cooum and Adyar.
According to Sundarrajan, nearly 500 years ago, Chennai had 30-50 major drains and 540 smaller drains. When it rained, smaller drains carried surface runoff to larger drains which in turn carried it to the major rivers and finally the rivers merged with the sea, he adds.
He also says that Chennai has been blessed with a natural ecosystem comprising Ennore Pulicat creek in the north and Pallikaranai marshland in the south.
However, rampant encroachment has continued largely unchecked in these sensitive zones which act as a natural sponge that absorbs rainwater and replenishes aquifers.
In 2020, the Save Ennore Creek campaign had in a report to Union Home Minister Amit Shah alleged that more than 660 acres of backwaters of the Kosasthalaiyar river had been encroached by public sector undertakings (PSUs). Kamarajar Port, it claimed, encroached 114 acres, while the coal ash dump for NTPC Tamil Nadu Energy Company Ltd (NTECL) took up 203 acres, and Bharat Petroleum another 100 acres of land.
“The Ennore creek land, which was a spread of over 10,000 acres, has shrunk as a result of encroachments by Chennai Metro Rail Limited (CMRL), ports like Kamarajar port and the Kattupalli port. Ennore is completely distorted, it has become saline with lots of thermal power stations, there is fly ash deposited all over and it has got traces of mercury deposits,” says Professor S. Janakarajan, president of the South Asia Consortium for Interdisciplinary Water Resources studies.
“Ennore is completely polluted and its biodiversity is dead,” he adds.
Janakarajan reiterates that wetlands, marshlands and inland water bodies are “very important critical ecological units that protect biodiversity, recharge groundwater, and store rainwater; when you distort them, encroach them, it leads to ecological degradation”.
Experts also point out that despite encroachments and the release of 45,000 cusecs of water from Poondi and Puzhal reservoirs, the Ennore Pulicat wetlands helped northern Chennai from marooning completely.
“It has a huge flood carrying capacity. That is the only reason why we are saying you should not expand the Kattupalli port because it will bring huge threat to Pulicat, Ennore and will lead to complete inundation of northern Chennai in the future,” says Sundarrajan.
Developed by L&T, the Kattupalli port was acquired by Adani Ports and Special Economic Zone Ltd (APSEZ) in 2018. The next year, Adani Group said it planned to expand the port from the existing 330 acres to 6,111 acres. Of this, more than 2,250 acres was to be land in the sea covered by dredged sand.
ThePrint reached Adani Group for comment via email but had not received a response by the time of publication. This report will be updated if and when a response is received.
As for southern Chennai, Jayaram says at least 1,000 acres of land in the Pallikaranai marshland was illegally registered between 1990 and 2014.
The city’s only urban wetland, Pallikaranai marshland shrunk to a mere 600 hectares in 2013, from 5,500 hectares in 1965, an amicus curiae appointed by the Madras High Court had noted in his report in 2019.
Encroachments, reclassification of land use
Though the Tamil Nadu Protection of Tanks and Eviction of Encroachment Act, 2007 prohibits reclassification of water bodies, a PIL filed by Arappor Iyakkam in 2019 had put the state government in a fix after it was alleged that the Thamaraikani lake in Semmencherry had been converted into an ‘institutional use zone’ for the construction of a police station.
The Madras High court stayed the use of the police station and ordered a two-member team from the Indian Institute of Technology (IIT) to determine whether the land in question was a water body or not. In its observations, the court had noted that the police station would have to be demolished if it was established that it was built on a water body.
The case is still pending before the court.
“The CMDA, the urban development authority, despite the Supreme Court and high court saying that water bodies cannot be reclassified, have reclassified lands based on requests from the revenue and registration departments. This is dangerous as the three departments are colluding and reclassifying lands,” Jayaraman tells ThePrint.
Sundarrajan refers to how Chennai’s Long Tank and Lake View once had water bodies.
“Long Tank was from Villivakkam to Mambalam (close to 11 km) but now what remains of the tank is the sole Chetpet tank that is still there,” he says, adding that the Valluvar Kottam monument in Chennai was once a lake.
He adds: “The irony is that Valluvar Kottam, a monument dedicated to the Tamil poet philosopher Thiruvalluvar, is built on a lake and Thiruvalluvar had said ‘no life can survive without water’.”
Desilting, river rejuvenation
In the aftermath of the flooding last week, Chief Minister M.K. Stalin had said that the Rs 4,000-crore stormwater drain system, implemented in a phased manner since 2021, reduced the impact of the downpour.
This system, say officials, is also why it did not take as much time as it used to earlier for water levels to recede. Sixty percent of the rainwater was drained out within 48 hours after it stopped raining, says Radhakrishnan.
He reiterates that the city received more rainfall than considered the usual during the northeast monsoon and double of what is considered the usual during the southwest monsoon.
This meant that the city’s holding capacity for rainwater was nearly saturated.
“The city during the southwest monsoon on average receives 44 cm but this year since 1 January, the city received 82 cm. Moreover, in Chennai, the average northeast monsoon is 79 cm but this time the city has already registered 114 cm,” says Radhakrishnan.
The Greater Chennai Corporation, he adds, maintains 33 micro canals, whereas the water resource department maintains 14 canals, besides the Buckingham Canal and the three rivers.
At present, the city has 3,331 km of stormwater drains.
“At the time of the storm, three river mouths got clogged as the sea water level was high and the city became like a reservoir holding 67 TMC (thousand million cubic feet) of water for about 44 hours,” says Radhakrishnan.
The civic body, he adds, made efforts to desilt all major canals and laid nearly 3,900 roads again in anticipation of the northeast monsoon.
“Since 2021, 12,000 encroachments were removed from Buckingham canal and encroachments near the Adyar river were also removed to a large extent,” he says, adding that the Chennai River Restoration Trust (CRRT) has been working to restore, deepen, and clean up the rivers.
Initially called the Adyar Poonga Trust, the CRRT was formed in 2006 by the state government to protect water bodies. The chief secretary of the state is ex officio chairman of the trust.
According to the state government, the trust had spent Rs 790 crore since its inception, of which Rs 129.22 crore was spent on dredging, widening, and strengthening the banks of two rivers — Adyar and Cooum — while another Rs 122.99 crore was spent on construction of perimeter walls and fences, and Rs 20.75 crore on plantation of trees and beautification.
Other measures to prevent water logging include the construction of a stormwater drain spanning 406 km, covering the Adyar and Cooum basins, at a cost of Rs 1,387 crore. Work on a 769-km stormwater drain in the Kosasthalaiyar Basin too is expected to be completed by March next year, while work is also underway on a 360-km drain in the Kolavam Basin.
The government had in its budget for this year allocated a sum of Rs 1,500 crore for the restoration of a 44 km stretch of the Adyar river through public-private partnership model.
Sundarrajan, however, underlined that to de-silt and maintain existing water bodies, besides keeping them free from encroachment, is key to ensuring that surface runoff can be stored for later use.
(Edited by Amrtansh Arora)
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