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Monday 25 July 2011

Go Green

Water Words In a very special initiative on water conservation, DHiE is proud to collaborate with a man who has adventurously used rainwater, not just to reduce his energy bills but also to show Bangaloreans that protecting the environment and saving precious water is really a matter of common sense. Meet A. R. Shivakumar, Principal Investigator, Rainwater Harvesting, Karnataka State Council for Science and Technology, Indian Institute of Science who gets very indignant about the terribly wasteful manner in which we use natural resources like water and sunlight. That is why when he built his house ‘Sourabha’ in Vijayanagar, he consciously adopted several techniques. He installed rainwater pipes to recharge groundwater and harvest rainwater for use and he ensured that all waster usage points like bathrooms, toilets, kitchen and utility area came as close as possible to an open duct which carries all the pipes. The drip and sprinkler irrigation system cost Rs.320 to install and the rainwater harvesting equipment costs Rs.150 while the rainwater charging cost Rs.1,600. Nature has paid him back in full measure. Over the years while his neighbour’s bore wells have failed to yield water at 350-450 ft. He gets water at 130 ft. The house was built in 1995 and has since been entirely dependent on rainwater for all its needs. And when he got the water tested he found it clean and uncontaminated.

A R Shivakumar, Principal Investigator – Rainwater Harvesting, Karnataka State Council for Science and Technology, Indian Institute of Science.

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The secret to Shivakumar’s success lies in rooftop rainwater harvesting. He will share more such exciting secrets with you and if you follow his sincere advice, you can lay claim to such riches as pure water and dramatically reduced power bills. Rain dance on the rooftop

Rain dance on the rooftop Bangalore is a unique city because it has neither river nor sea. Our erstwhile rulers had planned lakes and water bodies to collect rain water. It was the most systematic, common-sense community approach to address the water needs of the population. The water thus collected was used through ‘kalyanis’ or step wells and open wells. Open wells were recharged by tanks, water bodies and surface water flow. But as urbanisation happened, this approach could not be sustained. Water sources got polluted and dried up. Encroachment and diversion of natural drainage of rain water soon turned most of these tanks into garbage dumps!

Ulsoor lake. We began to look at far off places like Hesarghatta and Thippagondanahalli for water supply. As demand continued to mount, we went up to 95 km to River Cauvery to meet our water needs. And now we are in the unique situation of pumping water (a whopping 98 per cent of our requirement) from a distance of 95 km against a gradient of 500 metres! Urbanisation and increase in population are exerting tremendous pressure on conventional water supply. The time has come to look for new sources or at recycling water. Recycling is not a phenomenon that is well-accepted in India due to social reasons. We just cannot imagine recycling our bath water! Why fret when there’s an easy solution on hand: Rain Water. It is available in abundance in a place like Bangalore which receives 1000 millimetres of rain water (or 40 inches of rainfall) annually. This translates to 2,30,000 litres of pure water in a plot of 2400 sq ft — a plot where an individual can comfortably build a house/ apartment. When we have such a boon, why don’t we use it? If we do, at least 50 per cent of our water requirement can be met with intervention. And the pressure on a service provider like the Bangalore Water Supply and Sewerage Board (BWSSB) will dramatically come down. The BWSSB currently supplies water to 6,25,00 properties.

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If everyone practices rain water harvesting in Bangalore, an equal number of new connections can be facilitated and in the next 25 years, Bangalore can still sustain with its available water sources.

Kalyani. So what exactly is rain water harvesting? It is a very simple intervention to collect rain water. The first and easiest approach is rooftop rain water harvesting. Collect the roofwater which is already flowing through a downwater pipe, attach a filter at the end of the pipe to separate the dirt, dust, bird dropping and leaves and divert the filtered rain water into a storage unit such as a tank/ sump. This can give you sustained water supply during the rainy season. The excess water which overflows from the sump or tank can be used to recharge the groundwater through a pre-cast cement ring open well. When the rain water is discharged into this well, it slowly percolates into the groundwater table and can be withdrawn through a borewell or an open well. These two systems can provide sustained water supply through out the year. Rainwater can also be collected in playgrounds, parks and roads for large-scale groundwater recharge. Harking back to the time when I was in school, I remember fetching water twice a day from an open well outside my village, Ammanaghatta in Gubbi taluk inTumkur district. I did this religiously all through my childhood! I saw piped water only when I moved to Bangalore. But soon the borewell in our house in Vijaynagar dried up and I had to fight for water for the first time in my life! At that time, I was working on sustainability projects. So I started planning a house which would use Nature’s gifts for its needs. The outcome is ‘Sourabha’. I will take you on a tour of ‘Sourabha’, in my next column!