HARD LESSONS: Suburban pockets such as Balakrishna Nagar faced severe inundation in the recent spells of rain. — File photo: V. Ganesan

CHENNAI: The preliminary findings of an ongoing status survey of the city's network of stormwater drains and waterways indicate that man-made factors were responsible for maximising the chaos that reigned in Chennai and suburbs after the recent spells of rain.

Encroachments on embankments of water bodies, dumping of plastic and other forms of waste into canals eventually paralysing outflow and widespread letting out of household effluents that polluted water bodies (and elevated the coliform count to pathogenic levels) were among the important reasons for flooding and water-logging in low-level areas in the city and suburbs.

The study is being undertaken by the Environmental Health and Biotechnology unit in the Department of Zoology, Loyola College and Department of Geography, University of Madras under a project titled `GIS Strategy for Stormwater Management in Relevance with Public Health Issues of Chennai Corporation Area'.

The project is funded by Ministry of Information Technology, Government of India.

A classic example

"North Chennai is a classic example of things gone wrong," said S. Vincent, Reader at Loyola College faculty and principal investigator along with N. Sivagnanam, Head of Geography, University of Madras.

The survey of stormwater drains and waterways for over three months, found that in some places, the flow was forced in the opposite direction due to human interference. Uneven desilting of the channels had led to stagnation of water while high reefs contributed to blocking the movement of water.

Maintenance

Proper maintenance of storm water drains and waterways are very important to avoid flooding and water logging after the rain. "The efforts will pay off in the long term, but only with the co-ordination and involvement of the public," Mr. Vincent said.

Though stormwater drains are supposed to be dry to facilitate free flow, often they are turned into receptacles of waste materials -- dumped by the public.

Shops, especially teas stalls and meat shops, were found to be regularly dumping their waste into storm water drains. The waterways had become dumping sites of household wastes.

The citywide survey focused more closely on North Chennai zones already identified as hot spots for many water-borne diseases. Laboratory analysis of water samples from stormwater drains from these areas found that the coliform count exceeded one lakh per 100 ml of water sample in many places.

The investigators attribute the frequent outbreak of diarrhoea and leptospirosis to the compromised public hygiene in these hot spots.

The investigators recommend enabling all stormwater drains with percolation facility to enhance the recharge potential of rainwater naturally.

Deepening of the canal mouths is also a major initiative to be undertaken for tidal action to remain intact on the waterways, investigators said.

An awareness drive on proper maintenance of stormwater drains and waterways will shortly be launched in the city, beginning with North Chennai, he said.

Printer friendly page  
Send this article to Friends by E-Mail