Chennai’s resilience to the recent deluge has taken a severe beating as nearly a quarter of its wetlands, open space and flood plains have given way to concrete structures. Months before the series of depressions and “freak” weather developments hit the city, researchers at the Centre for Ecological Sciences in the Indian Institute of Science (IISc), Bengaluru, tabulated the “worrisome” growth patterns of the coastal city.
The research, which is to be published in the Journal of the Indian Society of Remote Sensing, shows that since 1991, the city’s concrete structures have increased nearly 13 times. Correspondingly, flood plains and open areas have been reduced by a fourth.
The results were tabulated through a combination of satellite imagery, which was then superimposed over topological maps of the Survey of India as well as from the Chennai municipality.
“In cities like Chennai and Kolkata, marshes and flood plains play a very important role in draining out overflowing rivers. This doesn’t seem to have been understood by urban planners. One can’t encroach the buffer around rivers without consequences,” says T.V. Ramachandra, who authored the study.
Satellite images and predictive modelling show that the northwest and southwest zones of Chennai are seeing the most unplanned growth — an observation that correlates with not only the levelling of marshlands, but also the areas worst affected by the recent floods. “Is it worth sanctioning Rs.1,000-crore projects here, while spending more than Rs. 15,000 crore to restore normalcy to a flood-ravaged city?” asks Mr. Ramachandra.
While bad planning and destruction of marshy lands may have only exasperated the devastation of the floods, IISc researcher T.V. Ramachandra is quick to point out that along with other major metros, Chennai must address its greenhouse emissions that contribute to climate change.
His recent research on carbon footprints in major metros of the country, shows that Chennai tops the list in emissions per capita. The city releases nearly 4.79 tones of CO2 per person per year, while Kolkata comes a distant second at 3.29 tonnes per capita. The highest contributor is industrial emission, where 4.4 million tonnes of CO2 in the year studied.
