Water hyacinth remains challenge as WRD steps up monsoon works

The Water Resources Department (WRD) has expedited work to clear clogged waterways in the city ahead of Northeast monsoon. However, large swathes of water hyacinth remain a challenge, and residents have called for permanent measures to prevent sewage entering the waterways to address the issue.

According to the WRD, nearly 50% of the works, being carried out at a cost of ₹42 crore, has been completed so far. The annual exercise aims at clearing floating waste, debris, and large stretches of aquatic weeds in various major and minor waterways and water bodies in Chennai, its surrounding districts and Cuddalore district.

Of the total 528.44 km of waterways in five districts, nearly 104.74 km of waterways lie within the Greater Chennai Corporation (GCC) limits. The department has deployed about 400 machines, including floating (amphibious) excavators, to clean the waterways, including Adyar, Cooum, Kosasthalaiyar, and Araniyar rivers and Buckingham Canal.

The first phase of desilting work would be completed by October first week. This would help minimise floods in rivers and backflow into micro drains by 70% to 80% during the monsoon. “The rivers would be able to handle the flows without spillover even in the event of 200 mm of rainfall in a day,” an official said.

According to the department’s flood vulnerability assessment, the proportion of flood-hazard areas and population density were moving from the outer Chennai Metropolitan Area areas towards the GCC urban region.

Work is also being carried out to clear sand bars at the river mouths of Adyar, Cooum, Araniyar, Muttukadu-Kovalam estuary, and Pudupattinam sea mouth. The department is carrying out controlled opening of the river mouths to prevent seawater intrusion and ensure smooth tidal flow, officials said.

The monsoon preparedness works would be carried out in coordination with GCC and local bodies till the year end. Various flood mitigation works are also underway, officials said.

Residents stressed the need for permanent solutions to prevent sewage pollution in waterbodies and waterways, rather than relying solely on periodic cleaning.

K. Mohan, a rower and Thiruvanmiyur resident, said Adyar river has undergone some restoration efforts, including tree cover along the riverbanks and widening the river near the creek. The authorities must periodically remove the accumulated floating waste near the trash booms like in Nandanam. Regular maintenance of trash boom is essential to prevent solid waste and aquatic weeds from reaching the sea.

Residents also urged the authorities to ensure culverts are cleared of water hyacinth for free flow of floodwater during the rainy season.

Geetha Ganesh of AGS Colony, Velachery, said Velachery Lake and Veerangal Odai must be desilted to increase capacity. Sewage flow must be arrested to prevent vegetation and ensure groundwater recharge.