Buckingham Canal is the most polluted of the three major waterways in the city with nearly 60 per cent of the estimated 55 million litres of untreated sewage being let into it daily, including by Chennai Metropolitan Water Supply and Sewerage Board.
About 30 per cent of the untreated sewage gets into the Cooum river and the Adyar river takes the rest. is let out by residents living along the banks and even government agencies.
Sources in CMWSSB, known as Chennai Metrowater, said that 340 sewage outfalls into the waterways were identified last year. Of these, nearly 220 outfalls were through storm water drains. About 50 residential and commercial premises directly let out the sewage into the waterways.
Admitting that the water agency had itself resorted to letting out sewage from manholes and pumping stations into the three waterways, an official attributed it to the inadequate sewage collection and conveyance system.
Metrowater is taking various measures to strengthen the sewerage network to plug as many illegal outfalls as possible in the next one year. It also plans to issue notices to those letting out sewage into the waterways.
Storm water drains maintained by Chennai Corporation are estimated to carry around 10 million litres of sewage a day. The SWD in many areas, including T.Nagar, Korukkupet and Thiruvanmiyur, face this problem.
S.Kumaraswamy, a resident of Thiruvanmiyur, said: “In many places, people connect sewage into SWD. This leads to breeding of mosquitoes even during peak summer. The act cause irreparable damage to the environment as the sewage affected the ground water.”
With the Water Resources Department (WRD) recently commencing work to remove obstructions in Cooum River, residents and environmentalists are looking forward to a permanent solution to rehabilitate the waterway.
Residents of flood prone areas want the width of the waterways to be restored to allow free flow of rainwater. V.M.Murugavel, a resident of Wood Warp near Elephant Gate, said the canal near his house was a breeding ground for mosquitoes. “For the past one week, mosquitoes have reduced as they have cleaned the canal on catamarans. If such cleaning is undertaken throughout the year, we will not have as many mosquitoes,” he said.
T.K.Ramkumar, principal advisor, Exnora International, said discharge from “informal settlements” was very minimal when compared to those from private and government institutions. “Though other basic amenities have been provided to residents of several areas, they do not have sewer lines. Common collection facilities must be provided in areas where settlements are at a lower level than the sewer network.”
He added that once the different sources of sewage into the waterways are stopped, there will not be any flow in them. After that the slush would dry up in summer. Over a period, the river would cleanse itself and only carry rainwater.
Sources in the Environment Department said the respective government agencies have been taking efforts to plug illegal outfalls such as those near Chennai Central railway station and in Pudupet. The department will co-ordinate with local bodies .
This, however, does not seem to have stopped more people from letting out sewage into the Cooum as the WRD plans to initiate a survey of such outfalls into the river. Sources in the department said Chennai River Restoration Trust work has slowed down over the past few months .
It was found during a survey that there were more than 130 sewage outfalls in the Cooum and a majority of them were between Aminjikarai and Nungambakkam. The WRD has begun cleaning Cooum at a cost of Rs.1.02 crore and the work is expected to be completed within a fortnight.
As regards changing the situation in the Adyar, Metrowater has decided to approach Adyar Poonga Trust seeking assistance. .