CHENNAI: The heavy downpour that took hold of the city this month has created rivers of water flowing from buildings, apartments, office complexes and shops onto the roads, adding to the growing puddles that have left people waddling their way through the city. At this point, a solution that may not seem immediately apparent but can plug quite a few of monsoon woes has been pointed out by a handful of residents — Rain Water Harvesting (RWH).
Given the need to channel the excess water around the city, experts reveal that it may not be as outdated an idea despite the initial buzz about it waning a decade ago.
“Many houses and apartments in the city still have a fully functioning RWH system from when the government made it mandatory in 2003. But it’s not sufficient to merely have a unit. Maintenance also must be done once a year. If every house can do this, a huge percentage of the water shortage issue can be effectively sorted out,” said a Metrowater official to City Express.
Maintenance does not imply elaborate efforts, but simply cleaning the set-up to rid it off leaves, dirt, mud and other sediments that usually clog the percolation points. Rain Centre, a one-stop RWH resource centre that helps people set up their own water harvesting measures splits conservation into two groups - for immediate use, and for water-table storage.
R Raghunandhan, a resident of Greenways road has been harvesting rainwater with the help of Rain Centre for years now and says that even during the most severe summers, the water level does not dip below 10 feet. “The quality and availability of water we get through our RWH set-up is so rare in a city like Chennai,” he says.
In his apartment, he has saved the terrace outflows and drive-way run offs by building concrete trenches, directing them to recharge wells. This water would otherwise have flooded, spilling onto roads. “The harvested water is also potable,” says another resident of the apartment complex.
Depending upon the soil conditions and type of building, there can be many variations to the RWH design. The simplest of designs consists of collecting rainwater from the building roof-top and ground level surfaces and filtering it through a chamber of bricks and sand, then using a percolation pit to channel it underground for recharge. “Something as basic as getting a flexy pipe and connecting one end to your roof’s water outlet and other to supply well can also work,” says Shekar Raghavan. “There is no single fixed way of saving rain water.”
“RWH is especially useful for people living in the OMR. You can recover the cost within a few months itself,” adds Raghavan.
A clayey or rocky soil area would need a deeper recharge well of, at least 15ft depth, as these less porous substances would reach several feet before water can find easy percolation. But a sandy soil area, on the other hand, finds rapid percolation making it ideal for RWH, needing only a maximum of 10ft deep recharge wells.
Residents can claim free guidance to set-up RWH by calling up Rain Centre at 04424616134.