The Chennai Metropolitan Water Supply and Sewerage Board (CMWSSB) has taken up repair of sewer lines damaged when roads caved in or when they developed leaks at several locations across the city.

The water board plans to engage a consultant to assess the network and take up improvement.

During last month’s heavy rain, the sewer network carried almost double the usual load of 620 million litres a day (mld).

This left the network damaged at several places and caused cave-in on roads across the city, particularly in Zones 9 (Teynampet), 10 (Kodambakkam) and 11 (Valasaravakkam), said the CMWSSB officials.

The pipeline network in these places was over three decades old and carried sewage round the clock.

Normally, the peak flow would be for four hours during morning and evening hours.

Officials said work was in various stages of completion at 180 locations, including in Kathivakkam, Ennore and Vanagaram. While the repair taken up on Anna Main Road, K.K. Nagar, is a major work, the water board is also replacing the damaged portion of the sewer lines.

In Brindavan Street, T. Nagar, a portion of the road caved in on Wednesday and work is on to assess the damage and complete the repair work within two or three days.

Complaints resolution

Most of the work pertains to replacing damaged pipelines for a length of 10 metres or 15 metres as of now.

“We are carrying out temporary work to provide immediate relief to residents. Of the 20,460 complaints received since the start of monsoon, 18,215 have been resolved. Work is under progress to address other complaints,” said an official.

Another reason cited for road cave-in was damage to sewer lines during laying of cables by other utility agencies.

Pipelines in these places developed leaks that caused caving in of roads.

Maintenance doors that had collapsed like the one in Velachery Main Road were being replaced and leaks in water supply pipeline, including the one on Chamiers Road and Turnbulls Road, would be plugged.

The CMWSSB is executing the work to remove silt in the sewer lines at 520 locations identified in the city.

A major project would be drawn up based on the consultant’s report to improve the sewer lines, which runs for 4,093 km, keeping in mind the growing needs of the city, the officials said