Your house and Bangalore need not depend on the Cauvery. An effective RWH strategy and good designing can work wonders. M.A. Siraj studies a plot

He personifies the ideas he conceives and would like the State and the people to pursue them. A. R. Shivakumar, Principal Investigator for Rainwater Harvesting (RWH) at the Indian Institute of Science, lives by his words and vision, allowing no deviation from the dreams he offers.

His house in Vijayanagar has no BWSSB connection, for he consumes no water supplied by the City’s official water supplier. Nor does he entertain any water tanker suppliers. His needs are met by water harvested during rains and collected in an underground as well as overhead tank in his house built on a 60 ft. by 40 ft. plot.

The scientist at the Karnataka State Council for Science and Technology (KSCST) has been working on rainwater harvesting for close to 20 years and has been instrumental in helping the State Government formulate civic laws for bringing in rainwater compliance from the people.

Shivakumar is a staunch believer in living a green life and an ardent practitioner of rainwater harvesting and tapping solar energy. His house has been built in a way that it can collect the entire precipitation over the built-up area of the plot. Shivakumar says the house can collect nearly two lakh litres of rainwater annually and that is more than what he and his family members require for their needs during the 365 days. “Clean and safe water is available to us 24 hours throughout the year,” he adds.

The scientist has never forgotten his childhood in Amanghatta village in Tumkur district when he and his sisters would wake up at dawn to fetch water from the village well. So, when he started building his own house in Bangalore he wanted it to be self-dependent. Roofs were covered with solar panels, storages were built to tap and store rainwater and provision was left for sunlight to reach the kitchen at all hours of the day as it is equipped with solar cookers.

But that was not all. The family practised a host of guidelines to make abstemious use of water. Says he: “We do not use more than 300 litres of water a day. Even the maid has instruction not to have more than a quarter bucket of water for mopping the floor. That is quite sufficient for the purpose.” In addition to this, the outwash from the washing machines is directed to the toilet flush tanks, thereby saving freshwater from going down the drain.

He also had his roof painted white to reflect back the sunlight thereby ensuring that much of the heat generated inside the house comes down drastically. The family composts much of the organic garbage and has planted enough bushes around the house to avoid internal curtaining of windows.

According to Shivakumar, the monsoon precipitation brings around 929 mm rainfall in an average year to Bangalore. The area under the BBMP is roughly around 800 sq. km. The 16 lakh property have a combined roof area of around 110 sq. km which works out to over one-eighth of the total area. The city receives 21 tmc ft. of water through rains. Of this, 3.6 tmc ft. falls over roofed area while 17.6 tmc ft. falls over the open area. An effective rainwater harvesting strategy can trap the entire water which could effectively stall fresh demand on Cauvery water, 19 tmc ft. of which is allocated annually for the BWSSB. Even the rains that fall on open spaces could be either trapped in soak pits or made to flow into existing lakes and surface water bodies.

Shivakumar says countries such as China, Brazil, and Sri Lanka have stricter norms and higher compliance of rainwater harvesting. He says an effective strategy for sustainable water supply for Bangalore should envision reducing the dependence on Cauvery water to merely 50 per cent of the needs of the city. Another 20 per cent each could be obtained through RWH and ground-water while recycling could bring in another 10 per cent. He suggests making it mandatory for industries and larger establishments like the Railways to use the recycled water.

He suggests that the BBMP bring in stricter enforcement of RWH in both new and old property and construction of 5,000-litre rainwater tanks in all property larger than 110 sq. m. The 700-plus parks and gardens should be made RWH-compliant with recharge and open wells. He also envisages laws to allow the bigger establishments to withdraw groundwater only proportionate to the groundwater recharged in their premises.