For Chennai, a lesson or two from Copenhagen on ‘flood-proofing’

Chennai may be water-starved today, but the memory of the December 2015 floods, which claimed many lives, cut off the city from the rest of the country, rendered thousands homeless, and shut down businesses still lingers.

It took months for Chennai to return to normal.

However, from across the oceans, there is a lesson to be learnt in making the city flood-proof. That’s the demonstrable claim of Morten Kabell, Mayor of Technology and Environment, Copenhagen, during a recent interaction with a team of Indian journalists at his office here.

The Danish capital faced the worst floods in 500 years in 2011 after just two hours of rain. The basement in many houses was flooded, and property worth €1 billion (about ₹7,000 crore) was damaged. People began to secure their basements in response, but the tragedy hit them again — four times, even if it was withless severity.

It was then that the city decided to make itself ‘water-proof’ and partnered with Ramboll, a design and management consultancy firm, to lay the infrastructure. “With climate change looming, there is more possibility of rain, and we want to be prepared,” Kabell added.

The so-called ‘blue-green infrastructure’ attempts to make the city greener and equip it to handle flood water. First, more area is cleared along the riverfront, which will be converted to parks lined with trees and greenery. The streets are then re-engineered to contain the storm water on the surface and re-route it to the river. This way, even if the water overflows, it will flow into the park and not onto the pavement. Kabell said, “Every district will benefit from the infrastructure project.”

The infrastructure, with an estimated cost of €1.6 billion (₹11,000 crore), will take 15-20 years to be completed. The Danish government has given a loan to the city administration for the project, which started in 2015; the money will be paid back through higher realisations on water bills.