“When we build our dream house, we plan so meticulously that even small things are paid attention to in advance. But how many people actually give attention towards having rainwater harvesting structures?” asks well-known water conservationist N.J. Devaraj Reddy.
Mr. Reddy, a hydrogeologist and rainwater harvesting consultant, says that water woes would have been solved in most of the areas of the State if serious efforts had been made to create public awareness about the importance of rainwater harvesting.
According to him, Karnataka has a good potential for rainwater harvesting though there are differences in terms of average rainfall received by different regions. “But what is most important is that people should show interest in rainwater harvesting by recognising its importance,” he says.
“Rainwater harvesting is not just about tapping nature’s precious resource and conserving water. The most important thing about rainwater is its quality and taste,” he said. “The quality of rainwater is superior to that of the treated water being supplied in any of the metros, including Bengaluru.”
Mr. Reddy, who has helped a large number of individuals and organisations to adopt rainwater harvesting technology, prescribes a usage model too. “Since rainwater stands for quality, it should be used mainly for drinking and cooking purposes. It could be used for bathing too, only if you have adequate storage space. Through this, you can use rainwater throughout the year, including the summer, even without a big storage,” he says.
According to him, about 10,000 litres of rainwater is enough to take care of the drinking and cooking needs of a family of four or five throughout the year. He suggests that water supplied by government agencies such as Bangalore Water Supply and Sewerage Board (BWSSB) could be used for bathing and other requirements, while borewell water could be used for cleaning and gardening. “The idea is to ensure that the best-quality water — rainwater — is used for drinking and cooking,” he says.
Roof space is not a constrain as even small Ashraya houses with an area of just 10x20 ft, given to poor families, can yield about 13,000 litres of rainwater even in the parched areas of the State that receive minimum rainfall, Mr. Reddy says.
However, he expresses concern that the traditional builders generally quote higher prices for creating storage facilities such as underground sumps for rainwater harvesting. “The scheduled rates of the government prescribe the cost of sump construction at ₹20 a litre. But we have proved that it is possible to reduce it to below ₹5 a litre,” he says, while referring to building a rainwater storage facility with a capacity of 2 lakh litres for Shantarama Thirthashrama Trust at Medehalli in Chitradurga district recently.
‘Vidhana Soudha should set an example’
Mr. Reddy, who is also a member of the State planning board, has appealed to political and spiritual leaders as well as educational and government institutes to inspire others by adopting rainwater harvesting.
Observing that the rainwater harvesting system adopted at the Vidhana Soudha did not appear to be functioning effectively or managed well, he says the Vidhana Soudha, being the State’s power centre, should lead the way. “Getting packaged drinking water bottles to Vidhana Soudha shows it in poor light. Vidhana Soudha must set an example by offering rainwater for drinking purposes,” he says.
Pointing out that the rainwater harvesting system adopted in a few government schools on an experimental basis is working effectively, Mr. Reddy suggests that more government schools should try it out so that they get clean and quality water for drinking and midday meals.
Groundwater table dips to 2,355 feet
The owners of plots who are planning to drill borewells in Bengaluru, beware. According to Mr. Reddy, such is the fast depletion of the groundwater table in some areas of Bengaluru that it has plummeted to 2,350 feet in parts of Electronics City.
“Recently, an individual drilled a borewell before building a house on a 30x40 ft plot in Electronics City. He got a meagre water yield of just a quarter inch, that too at a depth of 2,355 feet. For this, he ended up paying about ₹9.5 lakh as borewell and casing pipe charges. Considering such a huge depth, he would have spent another ₹4 lakh to ₹5 lakh on remaining things such as pump set, electric cable, and pipes, besides labour. Instead, he could have just spent about ₹5 lakh and stored much more rainwater than what would be available from his borewell of quarter inch yield,” he says.
Mr. Reddy has advised others facing similar issues to think twice before investing on borewells unnecessarily, as they can dry up within a few years.
