CHENNAI: The state government’s latest promise to transform the Cooum and Adyar into ‘world-class’ riverfronts has run into the old question of whether the city can clean its rivers while sewage, solid waste and urban debris keep entering them. Tonnes of pollutants are being flushed into the sea through the Adyar estuary and deposited on city beaches.
The government has announced global tenders to prepare detailed feasibility and project reports for restoring the two rivers, with a vision of boating, walkways, recreational spaces and clean riverbanks modelled partly on Seoul’s Cheonggyecheon and Singapore’s Kallang river. But the condition of Chennai’s rivers and coast may be pointing to a city which is still struggling with the basics.
The entire coastal stretch from Adyar bar mouth to Nochikuppam is carpeted with water hyacinth mixed with plastics, liquor bottles and other urban waste.
“The debris have been getting flushed into the sea for the last four days. The waves are bringing it back and depositing it on the shore,” said K Bharati, president of the South Indian Fishermen Association.
The Greater Chennai Corporation has been undertaking beach-cleaning operations, but fishermen said the recurring accumulation showed that cleaning the shoreline alone could not address the source. During Cyclone Montha last year, plastic, thermocol, bottles and water hyacinth washed out through the Adyar, and fishermen complained of spending hours removing plastic from their nets.
Marine biologist TD Babu said the recurring removal of water hyacinth is an example of treating the symptom rather than the cause. “Clearing water hyacinth is like firefighting. It is addressing the symptoms and not the disease,” he said, adding large sums are spent repeatedly on machinery and removal.
“If they just plug all the sewage getting into the river, hyacinth will not be there at all. They need to address the root cause. For decades, the same thing has been happening. This is not a sustainable model,” Babu said.
Porur lake, an important drinking water source for the city, is currently covered extensively by water hyacinth, with machinery deployed to remove the growth. Porur has historically been used as a potable-water source and studies have identified it, along with Puzhal and Chembarambakkam, as vulnerable to pollution because of their location amid densely populated areas.
Babu said the condition calls for water-quality testing, including for faecal contamination such as E. coli, rather than just removing the vegetation.
“We never know what is in the water. The fact that the lake is fully carpeted shows that it has been left unattended,” he said. TNIE had reported in 2019 that sewage from residential areas was flowing into the Thanthikal canal, which carries water towards the lake.
Government data reported this month showed nearly 7.5 crore litres of sewage and sullage flowing daily through 65 open drains in 18 urban local bodies around Chennai, with substantial quantities ultimately reaching waterbodies and the Cooum and Adyar systems.
The river plan is the latest in the series of long history of restoration announcements, including an earlier `1,500-crore Adyar proposal with a 70-km sewerage pipeline and 14 sewage plants of 110 MLD combined capacity. “Every budget, there will be something, but we have not seen improvement,” Babu added.
