Reality Check: Are New Stormwater Drains Keeping Chennai Free From Flooding?

The Chennai Corporation completed the drain work in the core city before the onset of the north east monsoon.

This year, the Chennai Corporation came up with an ambitious project of upgrading 200 km of stormwater drain networks, to prevent waterlogging.

(Image: Smitha TK/ The Quint)

Reporter & Cameraperson : Smitha TK

If Bengaluru is synonymous with potholes, then Chennai is known for being dug up for months on end, due to unfinished public works. Come November, and rainwater and sewage freely flow on the streets of Chennai.

Every year when the northeast monsoon sets in, the common sight is waterlogged streets, and it takes over a week for the water to be drained.

But after the first spell this year, the traditional flooding hotspots didn't experience any water stagnation, and inundation was restricted mainly to parts of North Chennai. 

How was this even possible?

The Quint traveled across the city to understand how the city Corporation's preparedness and its ambitious stormwater drain project actually paid off, to a large extent.

An Ambitious Project, Executed in Quick Time

This year, the Chennai Corporation came up with an ambitious project of upgrading 200 km of its stormwater drain networks, to prevent water-logging.

The project set itself a challenging time frame - before the onset of the north east monsoon, which began in the last week of October. What should have taken 12 months, was done in less than eight months.

As of early November, the Chennai Mayor claimed that 90% of the project work had been completed in the heart of the city.

This year the Corporation focussed on engineering, using precast causeways, modern machinery for cementing walls and top slabs and increasing the number of manholes for greater access to ensure better flow. There was also an intensive de-silting process, much ahead of the monsoon.

This year, the total rainfall in many areas was nearly 33 cm over a three-day period, whereas last year, the city was inundated during the same period in November, after only 17 cm of rainfall. 

Chennai has witnessed extreme climatic conditions since 2015.

(Image: Smitha TK/ The Quint)

Chennai has witnessed extreme climatic conditions since 2015.

Areas in the core city, T Nagar, Adyar, Mylapore, Ashok Nagar and Velachery, did not face any water-logging this year.

For the first time in seven years, Seethammal Colony in Alwarpet was not waterlogged after the November rains.

(Image: Smitha TK/ The Quint)

‘New Storm Water Drains were Laid in a Scientific Manner’

This was a pressing issue since the disastrous 2015 floods. In 2021, when MK Stalin's Dravida Munnetra Kazhagam took over the state, they had promised to come up with a permanent solution. Also, the Corporation Councillors had been elected after a gap of a decade, and so they felt directly answerable to the residents of Chennai.

Gagandeep Singh Bedi, the Chennai Corporation Commissioner is carrying out this project meticulously to ensure the old drains that date back to the British era are also connected to the new network.

The project was completed in a tough time frame - before the onset of the north east monsoon, which began in the last week of October.

(Image: Chennai Corporation)

The Thirupugazh committee, an advisory panel on mitigation and management of flood risks in the city, submitted detailed maps of the old network and noted that some of it was in shambles. There were problems with the gradients of the drains, which hampered the proper flow of storm water. They estimated that 60% of the drains were choked with sewage.

Experts say that the biggest takeaway after this first spell of November rains was that the old infrastructure needs to be maintained regularly.
Of the city's 560 flood prone areas, drains were constructed in 130 places. Most of the other areas mainly required maintenance and removal of encroachments, an expert working with the state told The Quint. 

An official told The Quint that this was the first time a storm water drain project of such proportions has been taken up in Chennai.

The new storm water drain network was laid in a very scientific manner, after measuring the levels and checking the gradients. They de-silted the 2,400km long network of storm water drains, way ahead of the monsoon. We will see the complete impact of the new network only next year.

Professor S Janakarajan, Former Director, Madras Institute of Development Studies (MIDS)

The Locality of Taramani - Nov 2021 Vs Nov 2022:

The Chennai Corporation had also deployed over 20,000 workers on the field, actively pumping water or clearing complaints. Officials claim that regular inspections were also made.

So far, around 160 km of fresh drain work has been completed in the core city areas.

BUT... North Chennai did face Flooding

But not all of Chennai was free of water-logging.

Every year, the eight streets connected to Angalamman Koil at Pandalam witness waterlogging.

(Image: Smitha TK/ The Quint)

Every year North Chennai falls prey to flooding and the same happened this year. Just two days of rainfall severely affected Pulianthope, Pandalam, Strahans Road, Thiruvika Nagar and Kolathur with water at knee-level.

The Quint visited Kolathur, MK Stalin's constituency for a reality check and found that several streets were badly waterlogged.

Every year, the eight streets connected to Angalamman Koil at Pandalam witness waterlogging.

(Image: Smitha TK/ The Quint)

A waterlogged street in Kolathur, Tamil Nadu CM MK Stalin's constituency.

 (Image: Smitha TK/ The Quint)

"Every year we lose at least one appliance to the rains. It has become a routine affair for us to shift all our household goods to the first floor and watch our house fill up with sewage and sludge," said Bhagavathy, whose house was flooded this year as well.

"When they were laying the drains, they heaped sand on one end.
After the construction work, they have not bothered to clear it. So how will the water flow?" asked an 80-year-old resident Ramasamy.

The Metro Rail construction work and other civic projects across the city have worsened the situation in areas like Vadapalani.

Bedi claims that the bigger projects in north and south Chennai are being undertaken, but will take three to four years to set things right.

Haphazard Construction Work Costs Lives

While this ambitious project has saved a lot of Chennai from flooding, the construction of these drains has also come at the cost of a life, and several other accidents.

The construction of some of the stormwater drains were done in a haphazard manner.

(Image: Smitha TK/ The Quint)

On 22 October, 23-year-old journalist Muthu Krishnan died after an accidental fall into an under-construction stormwater drain at Jafferkhanpet. The incident exposed the dangers of open public works trenches without barricades, live wires lying haphazardly and iron rods protruding, even after construction work was completed.

Residents in Valsaravakkam, Vadapalani and Porur also told The Quint that the laying of the new drains had disrupted the water supply pipes, and so their metro water connection had been completely cut off.

A senior official working with the Chennai Corporation told The Quint that by 2023 the new drain network, coupled with the old one will help resolve this crisis entirely for the city. But the consensus amongst residents is that it is still too early to judge the effectiveness of the Corporation’s work. The city is expecting sporadic heavy rainfall for another month, which will give a clearer picture.

Professor Janakarajan noted that, "We need to factor in how climate change is playing a vital role in influencing rainfall patterns. If we receive unprecedented rainfall, nothing can prevent water logging and people should understand that."

Why does Chennai face a flood and a drought-like situation every year? Rampant corruption has led to unplanned infrastructure obstructing waterways, thus aiding climate change. We are trying to get some answers in our 2-part series -- Flooded But Parched in Chennai. Stay tuned to The Quint.