Residents of Urur Kuppam have been noticing large quantities of white foam near the broken bridge at the Adyar river estuary since Monday.
“It is an annual occurrence. We don't wade through it since the river mouth has a lot of garbage and water hyacinth plants. People are also catching freshwater fish, including large-sized keluthi , which are swimming downstream,” said Karunakaran, a resident.
Sources in the Water Resources Department said the flow of rainwater into the river led to the mixing of chemicals and sewage deposited in the waterbody which, in turn, led to foaming after heavy spells of rain. Such a phenomenon occurs during the northeast monsoon, when the winds are strong, they added.
Rise in pH levels
The sources further said the river was now carrying about 2,500 cusecs of floodwater downstream of the Nandambakkam check dam.
Sources in the National Centre for Coastal Research said that they have been regularly collecting water samples and noticing an increase in pH levels for the past couple of days.
