Water hyacinth chokes parts of Adyar river, sparks mosquito menace in city

Residents living along the Adyar river have raised concerns about the river being choked with water hyacinth, which blocks the flow and leads to a growing mosquito menace.

The stretch of the river inside the city limits is blanketed by aquatic weeds, resulting in water stagnation and creating conducive conditions for mosquito breeding. The lack of periodical clearing of the weeds worsened the issue, residents charged.

They also alleged that the trash boom barriers upstream of Thiru.Vi.Ka. bridge are sometimes lifted to release the accumulated water hyacinth downstream instead of clearing it.

Ram Shankar, founder of SWARAN (Save water and recharge aquifers network) and a Gandhi Nagar resident, said: “I had been noticing dense growth of aquatic weeds near the riverfront walking trail towards Kotturpuram over the past fortnight. Water hyacinth obstructing the flow has also led to a stench in that portion of the river.” The authorities concerned must also prioritise regular fumigation of the stormwater drain network in the locality to curb mosquito breeding, he said.

Krishna Mohan, a Besant Nagar resident, said: “The portion of the river near Kotturpuram appears cleaner during rowing sessions as the trash boom barriers effectively prevent weeds from floating downstream. However, water hyacinth accumulates up to a stretch of 200 – 300 metres from the confluence of Mambalam drain if the waste is not cleared periodically.”

The Water Resources Department carries out the desilting exercise of city waterways, including Adyar river, vigorously ahead of the northeast monsoon and during the rainy season with the funds allotted for monsoon preparedness efforts.

Officials of the WRD said the Greater Chennai Corporation cleared floating waste and aquatic weeds that were collected at the trash boom barrier points. The department would coordinate with the GCC to clear invasive weeds.

Funds are yet to be allocated for the department’s proposal to purchase about 50 machines to execute desilting works throughout the year. Though the National Institute of Ocean Technology recommended periodical dredging of the river mouth, it was carried out through a special drive only last monsoon. The work then was delayed due to paucity of funds.