Downtown

Storm water drains, source of pollution

There seems to be no end to the menace of storm water drains discharging sewage and liquid waste into water bodies and other open places in the southern suburbs of Chennai.

Constructed for the purpose of discharging rain water run off during the Monsoon into lakes and tanks, these drains for several decades have been responsible for contamination, pollution of water bodies in the southern suburbs of Chennai.

Alarming levels of pollution

The issue has assumed such alarming proportions that water bodies in the southern suburbs of Chennai that were once potable have now been thoroughly degraded. Water bodies located in the midst of residential localities, commercial establishments and industries are on the brink of extinction.

Among the more than 300 major lakes and tanks and many more smaller water bodies in the city suburbs, only a few have managed to survive the onslaught of pollution. Engineers of the Department of Municipal Administration and Water Supply told Downtown that urban and rural local bodies were under tremendous pressure from their elected representatives for constructing storm water drains to prevent streets and roads from flooding during the Monsoon.

However, funds of the local bodies were wasted on laying these drains especially in those places where they were just not necessary.

The condition of these drains only reflected the loss of several lakhs of rupees from the tax payers' pockets, according to residents of Ranganathapuram in West Tambaram, who point to the drains leading to the lake in their locality.

Residents also point out that local bodies administration did not attach much importance to proper maintenance of these drains, that were clogged with plastic and paper waste.

In the absence of underground drainage networks, local bodies had no other option other than creating storm water drains to keep localities free from stagnation of sewage.

According to residents, only storm water drains constructed along arterial roads in the southern suburbs such as Grand Southern Trunk Road and Velachery Main Road were well planned.

In a bid to keep storm water drains free from sewage and reduce the level of pollutants, a novel project was carried out in Alandur Municipality (now with Chennai Corporation).

Japanese technology

Using a Japanese technology of placing remedial bio blocks made from volcanic ash, the pilot project threw out encouraging results, but it was not approved for implementation by the State Government.

Liquid waste management plant

In Chitlapakkam, there is a liquid waste management plant where sewage flowing into the storm water drains along Balaji Avenue is treated at the plant before being discharged into Sembakkam Lake.

However, this project too has not been completely successful as sewage continues to drain into the lake from multiple entry points.

Effluents from commercial establishments

Preventing raw sewage from homes and effluents from commercial establishment from flowing through these storm water drains could not be contained considering the absence of underground drainage projects, engineers said.

Residents added that the biggest casualty of polluted and contaminated storm water drains was supply of drinking water.

This is because main and distribution lines passed through storm water drains and due to corrosive condition of these pipes, sewage mixing with the drinking water was common occurrence.


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Printable version | Jun 19, 2021 2:33:40 PM | https://www.thehindu.com/features/downtown/storm-water-drains-source-of-pollution/article3459253.ece

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