Defunct rainwater harvesting systems need a fillip

In 2002, when Chief Minister J Jayalalithaa, at the height of a monsoon crisis, announced that the State could not afford to waste even a drop of water and decided to usher in a policy making compulsory rain water harvesting systems in all buildings, it was hailed across the world for its ingenuity.

Detractors who questioned the viability of the policy were soon stumped with the city witnessing a perceptible, positive change in the ground water table. Residents began to realise the benefits of the recharging systems within a season of installation. Though the recent Aquifer Atlas, released by the Central Ground Water Board, has not specified Chennai as one of the probable places conducive for artificial recharge, various other surveys have validated the benefits of the harvesting systems.

Studies by the Chennai Metrowater Supply and Se-wage Board since the policy implementation, for insta-nce, have shown that the rise in water table levels immediately after the October monsoon saw much impro-vement with the systems in place compared to the previous years. In 2004, the tables improved as much as 13 feet in certain localities.

This helped the city tide over even crisis situations, when the summer showers failed it twice between 2004 and 2009.

While there was no doubt on the pros of the policy, what has now come under scanner is the maintenance of the systems that were put in place from 2002-2003. According to experts, as the legislation made the systems compulsory with a deadline, many buildings went for quick fix to satisfy surveyors. According to a senior official, as days passed, “ineffective” systems became defunct, thanks to the collection of silt in the pipes. “Many of these systems did not install filters that were recommended. Therefore, the pipes were clogged with silt within a few seasons, rendering the whole system useless,” the official said.

Sekhar Raghavan, whose NGO Rain Centre, a pioneer in water conservation movement, said that almost 50 per cent of the systems put up after the policy have turned ineffective. “Ground under Chennai is diverse in nature and it varies from locality. This was never taken into consideration when the systems were put up,” he observed. Many of the buildings failed to install recharge wells as recommended, largely fearing cost.

Experts also partly blamed the Chennai Corporation and the Chennai Metropolitan Development Authority (CMDA) for the current state-of-affairs.