Sabari Terrace has been setting up the structure since last November in phases

CHENNAI: Where’s the rain, did you ask? Come, take a peep into the sump at this residential complex in Sholinganallur . The four blocks of 56 apartments of Sabari Terrace have channelled rain water from their terraces to fill a 100,000-litre sump in the first three days of rain, from October 29 to October 31.

“Since last November, we’ve been setting up the rain water harvesting structures in phases. Only last month all the four blocks were connected to the sump. In the three days cumulatively it would’ve rained for three hours. But that was enough to fill our sump,” said the residents association secretary Harsha Koda.

Explaining the structure that was designed under the guidance of Rain Centre, he said pipes from the terraces are connected to let rainwater into two tanks of 3,000 litre capacity each, where water is allowed to stay to allow mud and solid particles to settle down. The tanks are connected to the underground sump of 100,000 litres from where water goes to a treatment plant, and is collected in another sump to be directed for use.

“Three corners of each terrace are connected to this network, while the last corner of each terrace lets out water into recharge soak pits to improve ground water table,” said Koda. Residents said the harvesting facility has reduced their dependence on metrowater considerably. Excess water from the sump is let out to soak pits using valves.

Koda’s wife Prabha planned the layout of the structure. About1,500 feet of pipeline was laid for the network that cost the association ₹2.5 lakh. “Of this, ₹50,000 has been recovered in terms of water savings since last November,” said Koda.

Conservationists said the apartment complex has yielded so much water from so little rain because the harvesting system is new. “A harvesting system has to be cleaned before every monsoon , if not twice a year. Or it would be useless as dirt and silt clog it,” said Sekhar Raghavan of Rain Centre.

