The Smart Cities movement and the post 2015 flood mitigation measures have created partnerships between city authorities, citizens and NGOs to restore and revive water bodies. Chennai even got the Smart City award for water management. But this year’s rains showed the cracks in the system that still need to be fixed, says E Jayashree Kurup
Chennai city is battling intense flooding due to the Bay of Bengal depression-led rains for the past few days. While the depression has eased and the rain warning has been lifted, the Northern parts of the city suffered hugely and left 14 people dead. This brings back memories of 2015, when the Central and Southern parts of the city struggled with overflowing of the Koovam and Adyar rivers, again led by severe rainfall.
As climate change intensifies, cities like Chennai which have low-lying topography, just 6-metres above sea level in North Chennai, will face the brunt of flooding. But, said Raj Cherubal, CEO of Chennai Smart City Ltd, in a podcast with the National Institute of Urban Affairs (NIUA), a couple of months ago, the solution is to change people’s behaviors. His effort is to create a network of citizen bodies, NGOs, consultants and lenders to revive ponds, lakes and marshes that have gradually been destroyed in the city.
Since the floods of 2015 when South and Central Chennai struggled with flooding of the Koovam and Adyar rivers, 1,000 of the 5,000 hectares of marshes in the city have been restored. This means that while earlier all the marshes were interconnected, now there would be built assets between them and during intense precipitation, the flooding would impact them. But the restoration of the 1,000 hectares creates space for the water to drain into the marshlands again.
The effort is to capture every drop of rainwater falling in the city, says Cherubal, in the podcast. However, while some amount of rainwater is stored in large underground tanks to be used later, a large amount does flood the city. The Smart City authority has been working with Resident Welfare Associations (RWAs) to create rain water harvesting pits wherever ‘puddling’ takes place, so that water can be pushed into underground aquifers. In fact, many RWAs have asked for wells in the neighbourhood which get charged with the water which would otherwise have created puddling.
Similarly, 20-30 temple tanks have been restored to enhance aquifer recharging. In a city like Chennai, where rampant drawing of water from the underground aquifers caused an influx of sea water into the freshwater channels in the 1990s, this focus on recharging aquifers is very important.
Since the Smart City project took off, Cherubal says 62 water bodies including lakes and ponds have been restored. The Greater Chennai Municipal Corporation too has used its own and available CSR funds to work on 210 water bodies and 60 temple tanks. For this effort the city received the Smart City award in 2020.
The battle, says Cherubal, has just begun. People have now started coming forward and joining the authorities in the effort. Tracking the size and location of water bodies that are now covered with debris is a challenge. Many NGOs and RWAs have joined the effort of going back to the maps and identifying the locations and the problems. Funds, he feels, are available. But the appropriate solutions have to be found first – whether it is desilting, planting trees, stopping sewage influx, creating STPs and restoring wetlands.
The Smart Bike project is to encourage citizens to use the smart electric bikes and go on water body tours. “This is one way of creating awareness about these water bodies,” said Cherubal in the NIUA podcast.
As a step forward citizens have been asked to participate in a hackathon organised by the Innovation Hub to throw out data about challenges in the city. They can come up with solutions of how to automate data collection, image processing, drone imaging, use of IoT devices and detecting sewage in freshwater bodies. “They normally come up with low-cost solutions that would strengthen this movement,” says Cherubal.
This year’s floods in North Chennai was attributed to all 14 canals being badly managed and the desilting process leaving much to be desired. Chennai’s water flows along its channels, such as the Nodal Buckingham Channel from Andhra Pradesh to Kovalam in Kerala, says Cherubal. This has been fixed in patches but in North Chennai this year, this too was not desilted enough.
Waterlogging and flooding take away from the prices of property and liveability of localities. It is heartening that some alliances with residents and city authorities have worked. But a city-wide movement is still a while away.