AR Shivakumar, a resident of Bengaluru, has not paid a penny for his family’s water needs for the last 20 years. A pioneer in water harvesting techniques, he believes in the mantra, ‘be the change you wish to see in the world.’ Shivakumar is the principal investigator for rainwater harvesting (RWH) at the Karnataka State Council for Science and Technology (KSCST). His house ‘Sourabha’ in Vijaynagar, Bengaluru, which he built in 1994, depends entirely on rain water.
As a child in Amanghatta village in Tumkur district, Shivakumar and his sisters would wake up at dawn, to fetch water from the village well. Therefore, when he started building his house in Bangalore, he wanted to ensure that it would be free from water woes.
“When my wife Suma and I were planning our dream home, it was our desire to have a house, where nature would fulfil our need for light, ventilation and water. We read studies conducted by the Indian Institute of Science (IISc) and realised that rainwater harvesting was the answer to our water requirements. Even the construction of our house was done, using harvested rainwater,” he recalls.
“Our needs are met by water harvested during the rains and collected in an underground tank, as well as an overhead tank,” explains Shivakumar, who has conducted various training workshops and awareness programmes on RWH. His commitment towards water conservation, was instrumental in establishing the ‘Sir M Visvesvaraya Rainwater Harvesting Theme Park’ – the first-of-its-kind in the country, in Jayanagar, Bengaluru.
Rainwater that falls on the roof is channelled into a 4,500-litre tank, built on the ground floor. The excess rainwater is diverted and allowed to percolate into the ground, through a system of percolation tanks. This system consists of four interconnected plastic drums that are buried underground, with their base cut open to recharge the groundwater. After the remaining portion of the roof water is cleaned by a popup filter, it flows into an underground sump of 10,000 litres capacity, under the car park.
Advantages of rainwater harvesting
- RWH is a quick solution, to increase the availability of water, in areas that have inadequate resources.
- It increases ground water levels and mitigates the effects of drought.
- It reduces rain water run-off, which may otherwise, flood storm water drains.
- It serves as a cost-effective method to reduce soil erosion.
However, its successful implementation, depends on the collective efforts of individuals, government bodies and builders. One can store rain water in tanks and use it to flush toilets, water plants, etc. Rain water can also be harvested, to recharge groundwater through recharge pits, dug wells, borewells, soak pits and recharge trenches.
The situation in Bengaluru
In the last three decades, Bengaluru has experienced eight years of severe to moderate drought. Although the city receives 1,000 millimetres of rain water annually (equal to 2,30,000 litres of pure water in a plot of 2,400 sq ft), rapid urbanisation has substantially reduced the percolation of rainwater into the sub-soil, while the quantity of run-off water in storm drains, has increased tremendously.
“At least 50% of the city’s water requirement can be met through rainwater harvesting,” maintains Shivakumar. “If everyone practices rainwater harvesting in Bengaluru, in the next 25 years, the city can sustain itself with its available water sources. Similarly, other places in India, should also adopt RWH. Every drop of rainwater that is harvested, will save us from a water famine,” he concludes.