CHENNAI: The long anticipated cleaning of waterways in the city may begin soon. Chief minister J Jayalalithaa on Thursday announced the allocation of Rs 300 crore for effluent treatment and other related works that would be carried out to check pollution of key water bodies across the city. The work mainly involves plugging the sewage outlets and strengthening the city's sewage network.

 The amount will be spent for sewage and effluent treatment activities on 337 locations in Cooum and Adyar rivers and Buckingham canal, an official release said. "We have identified 105 outfalls in Cooum river, 49 in Adyar river and 183 in Buckingham canal," said a metro water official.

 The initial allotment of 150 crore would be given to the Chennai Metro Water Supply and Sewage Board in installments for laying pipes and setting up and upgrading pumping stations, Jayalalithaa said. Metrowater officials were optimistic and said they expected to finish the work in 18 months.

 "The key work would be to upgrade old sewage lines that were built during the British era," said the official.

 "Many sewage pipelines are too narrow to cope with the current load and so leak into the storm water drain network, which in turn is connected to the river bodies. Besides, the British administration had themselves connected many manholes directly to river outlets to cope with system overload. All these will have to be changed," he said.

  "Pump stations too are old and need to be revamped," he said. "Once we plug the outlets, we need better pumping facilities to prevent system overload." Once the stations are revamped, sewage lines will be enlarged from six inches to nine inches. "This will reduce leakage into storm water drains. We will also plug the link areas and the direct lines to the water bodies. Upgrading the pumping stations and the main lines will take nine months."

In low-lying areas, where the flow of sewage is not normal, Metrowater plans to set up new pumping stations. "We have been working on this for a year and already identified lands to set the stations up," he said.