Nature enthusiasts have expressed concern over filling of tanks in the River Noyyal system with sewage mixed water.
They also point out that water stored in most of the tanks are not released scientifically to aid the natural cleansing process when there is heavy inflow due to rain.
P.K. Selvaraj of Perur Padithurai Pathukappu Iyakkam said that tanks such as Achankulam are currently storing polluted water as authorities have not released water in accordance with the inflow.
“The heavy inflow of water in Noyyal triggered by recent rain was an ideal opportunity for authorities to clean the tanks naturally by releasing water equal to the inflow. The releasing must be done by raising the shutters so that water gets out from the bottom of the tanks,” he said.
According to him, the channel connecting Achankulam with Noyyal had blocks at Anavaripallam due to which the tank did not get a good amount of rainwater. Instead, sewage mixed water flows into the tank.
Another nature enthusiast alleged that the authorities were not releasing water properly from most of the tanks to aid fishermen. Release of water using shutters could lead to losing the fish stock, their main means of income.
R. Manikandan of Kovai Kulangal Padhukappu Amaippu said that the outflow channels of tanks, including Sengulam, Perur Periyakulam, Valankulam and Vellalore tank are not maintained well due to which water could not be drained in accordance with the inflow.
“Dead fishes float in many tanks often when the pollution level increases,” he said.
According to the district administration, 24 out of the 25 tanks in River Noyyal system in Coimbatore district had 100 % of water as of Monday.
Prasath Selvaraj, an independent researcher, said that shores of Achankulam and many other tanks vanished after water was stored unscientifically, ignoring various lesser known species, resident and migratory birds.
“Several species of shore birds and depend on shores and shallow waters in tanks. Such birds lose their habitat when tanks are full to the brim. Also mixing of sewage is a threat to fishes and other living organisms” he said.