Can Chennai survive another flood?

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12th Nov, 2022. 11:10 pm
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Chennai, southern India, is experiencing extreme rains that are getting tougher to predict.
More than 400 people were killed by disastrous floods in Chennai seven years ago.
Since October 31, at least 26 people have perished in rain-related events.

More than 400 people were killed by disastrous floods in Chennai, southern India, seven years ago, and again the area is experiencing extreme rains that are getting tougher to predict. If the metropolis is prepared to handle the effects of shifting weather patterns.

After Friday’s torrential rains pounded the city, Chennai’s schools and institutions have been closed for the second time this month.

Videos showed residents of the coastal city of 12 million people wading through dirty floods that had inundated the streets and residential areas.

As additional intense rainstorms are predicted in the coming days, authorities are on high alert.

Only 10 days have passed since the city had its highest rainfall in more than 30 years on November 1, when the deluge hit.

Since October 31, at least 26 people have perished in rain-related events.

According to experts, rainfall have increased in frequency while also becoming more unpredictable, making it difficult for authorities to act quickly.

“No one could have predicted that the city would receive 140mm of rainfall in 24 hours right at the onset of the monsoon season earlier this month,” says Dr S Janakarajan, the president of South Asia Consortium for Interdisciplinary Water Resources Studies.

“It was an unexpected weather event where forecasts changed from morning to evening.”

In an effort to keep things under control, the state government dispatched motor pumps to drain waterlogged areas and sent assistance teams to areas hit by flooding.

However, experts warn the city will need to take much more action to reduce the impact of extreme weather conditions in the future and prevent a repeat of the fatal floods in 2015 as sea levels rise and heat waves worsen.

“The fact that water entered people’s homes at the very beginning of the monsoon season shows just how unprepared Chennai is this time,” says SA Haris Sultan, a member of anti-corruption watchdog Arappor Iyakkam based in the city.

Chennai, one of the biggest cities in India, is situated on the coast of the Tamil Nadu state.

The city serves as a center for both industrial output and the production of automobiles.

Chennai’s primary monsoon season is during the months of October and November, as opposed to the majority of India, which depends on rains from the southwest monsoon in June.

To manage its water needs throughout the summer, the city depends on the rainfall.

In order to address the situation in 2019, the city experienced a severe drought and was compelled to import 10 million liters of water per day from other districts.

However, Chennai is situated on a low-lying plain, with the majority of its areas being only two to five meters above sea level.

Chennai is one of 20 coastal towns worldwide that the Intergovernmental Panel on Climate Change (IPCC) has identified as likely to experience significant flooding by the year 2050.

The report’s principal author issued a warning that if temperatures in South Asia quickly climb, the city would experience a “double whammy of heat and humidity, plus cyclones.”

The local government undertook an ambitious initiative to construct storm water drains, which would collect surplus rain from the streets and drain them into the sea, in order to get ready for the monsoon season this year.

But after three days of intense rain in the first week of November, the city was completely under water, putting an end to all activity.

The city struggled to handle the crisis, according to climate scientist Dr. Roxy Mathew Koll, because of the monsoons’ increasingly irregular behavior.

“We now have short episodes of strong wind bursts and heavy rains which are less predictable and challenging to even monitor, let alone forecast,” he says.

Others claim that the city’s groundwater and drainage infrastructure is insufficient to prevent widespread waterlogging and to store rainwater for the summer.

“Most of Chennai has become buildings and roads,” says L Elango, a professor of geology at the city’s Anna University.

Large-scale construction and quick industrialization have taken place in Chennai during the past ten years; much of this growth occurred without a plan, without consideration for water flows, and without care for catastrophic weather occurrences.

Over 80% of the city’s land is under construction, per data from the State Planning Commission.

Prof. Elango claims that because of Chennai’s concrete topography, installing substantial storm water drains and groundwater recharge facilities is of little utility.

“Instead, the city’s administration should focus on integrating drainage systems of buildings and streets to connect them to reservoirs,” he says.

Rainstorms are occurring more frequently, which has also reduced the amount of time forecasting organizations and disaster response teams have to act quickly.

“Cyclones that used to take two to four days to develop from a weak storm to an extremely severe cyclone are now intensifying in less than a day’s time,” Dr. Koll says.

That’s why, he adds, the government needs to formulate long-term policies that “help coastal communities adapt to intensifying storms and rising sea levels”.

“We might need to redesign cities to create more open spaces and take measures for the flood water to sink.”

Prof Janakarajan agrees – he says the city needs to construct more rooftop structures to harvest rainwater and store it underground.

“If that is done, Chennai will not only be flood-resilient but also drought-resilient.”

Can Chennai survive another flood?

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