“There has to be better planning. About 50 per cent of a city's water supply can come from dams and rivers, 20 per cent from rain water harvesting, 20 per cent from recharged borewells and 10 per cent from recycled water. This is the only way we can sustain our supply,” A.R. Shivakumar, who has made rainwater harvesting his mission.
As the battle for Cauvery water rages on, one man seems unaffected by it all. A Bengaluruean he may be, but he has little reason for concern as he has not relied on Cauvery water for his home for 21 years.
Meet A.R. Shivakumar, principal investigator, Rain Water Harvesting (RWH) with the Karnataka State Council for Science and Technology at the Indian Institute of Science. An unusual expert, who practices what he preaches, he hasn’t bothered to get a Cauvery water connection in his home and survives entirely on the rainwater collected on his rooftop.He even makes sure rain water, the purest available in nature, is used by his family for drinking too.
Not a new convert to the concept, he has been relying on rain water harvesting to serve all his family’s needs for over two decades. All he does is store the rain falling on his rooftop in an air and light proof container, which stops it from spoiling and then filters it, using a simple silver sheet before channeling it around the house. Careful not to let even a drop of rain water go waste , he has dug percolation pits that soak it into the ground and improve the water table.
“Seeing the water crisis in Bengaluru when I started building my house, I began looking for alternatives two decades ago and studied the rainfall data of 100 years for a year and a half before deciding that this concept could work. Bengaluru gets intermittent rainfall spread over 70 days and heavy rain during the monsoon. Going by World Health Organisation (WHO) standards, the average requirement of water per person per day is between 135 and 150 litres. With this being the target, an individual with 40X60 feet dimension house can be self -sufficient with rain water, provided it is judiciously used. In a year 2.2 lakh litres of water can be trapped and stored. A family of five can survive with 1.8 lakh litres of water,” he explains.
Having done his homework, he designed his house, Sourabha, to store water on the first floor. Called zero energy water, it needs no power to store and use. “We have storage of 45,000 litres, but use only 1.8 lakh litres. The remaining is used to recharge the underground water table,” he explains.
Not only does he harvest rain water, but is also judicious in recycling it and conserving it where he can. Devising his own system, he stores the outlet water from the washing machine in a separate tank, and channels it for flushing of toilets in the house after allowing for natural aeration. The water used in kitchen too is collected and used for gardening. So all in all, only 400 litres of fresh or rain water is made use of by the household.
When it rains for a 100 days without a break, which is very rare in Bengaluru, water drawn from a shallow tube well, recharged by the rainwater, meets the family’s requirement. So successful has he been in his rain water harvesting over the years that the ground water table around his home rose from 200ft to around 40ft within one year of recharge.
Noting that Bengaluru has the potential to harness 22 tmcft of water per year from its sewage and storm water drains, he says no city in the future can depend on rivers or dams alone for its water supply.
“There has to be better planning. About 50 per cent of a city’s water supply can come from dams and rivers, 20 per cent from rain water harvesting (RWH), 20 per cent from recharged borewells and 10 per cent from recycled water. This is the only way we can sustain our supply,” says the water expert, regretting that although the Bangalore Water Supply and Sewerage Board (BWSSB) has made it mandatory for buildings on 30x40ft or bigger dimension sites to install RWH, very few have actually done so. And worse, no punitive action against those who have failed to implement it.
Bengaluru, which get an average rainfall of 900 to 1000 mm or about 40 inches of rain annually, has no water constraint at all, in his view. “The city is blessed with good average rainfall, which is far ahead of several countries. We need water for 365 days and we get rainfall for about 70 days,” he points out, adding that all it needs is a little planning to rescue it from the water crisis it confronts periodically.
Mr Shivakumar’s commitment to the cause of water conservation has made him much sought after in the country. Meghalaya, home to Cherrapunji, which gets highest rainfall in the country, has now asked for his expertise and technical know-how in conserving and utilising its natural water.
As for Karnataka, he has designed RWH models, which have been installed at several vital installations, including the Vidhana Soudha and the Chief Minister’s official residence, Krishna. Hundreds of plumbers, who have learnt how to install rain water harvesting tanks under his guidance, are all empanelled with the BWSSB today....