The rainfall statistics for a 100-year average from the Indian Metrological Department makes for interesting reading. After all this is the water endowment that the nation will receive for the year and will have to arrange to rearrange so as to ensure that water is available right through the year. One recommendation across the country is for all buildings to incorporate rainwater harvesting systems. What does this mean, say, for a school in the city of Bangalore?
Let us look at the rainfall pattern for Bangalore. You can look it up for many other cities on the website of the IMD >http://www.imd.gov.in/doc/climateimp.pdf
Rainfall (in mm) Jan: 4.90; Feb: 7.90; March: 10.0; April: 43.90; May: 111.90; June: 79.70; July: 109.70; August: 138.80; Sept: 185.90; Oct: 161.70; Nov: 59.20; Dec: 17.40; Total: 931.0
From the 100 years of rainfall data, 1901 to 2000, it is clear that the rainiest months are August, September and October.
The Buddhi School is located in the suburb of Dasarahalli to the north of the city. The campus building is itself unique, being built from earth blocks and with a lot of natural light and ventilation.
The school decided to integrate rainwater harvesting and waste-water reuse and recycling at the construction stage itself.
Filters From the 700 sq. m roof area all the rainwater is led through rainwater pipes into filters and thence to a 100,000-litre storage sump located within the school building below the dining room.
This way the school captures almost all the 630,000 litres of water falling on its roof in an average year of rain. This water is filtered once again and used to meet the school’s water requirements.
Not only is rainwater captured from rooftops, the school also captures the rainwater falling on the playground area and other surfaces and channelises it to another tank. This water is used for gardening and washing purposes.
The used water from the toilets and sinks is then led into a well-designed waste-water treatment system.
This treatment unit, also using hydrogen peroxide, treats the water to required levels and then reuses this for flushing the toilets.
With a combination of rooftop and surface rainwater harvesting and waste-water reuse, the school is able to meet a large part of its water requirement on its own. Additional water, if required, is met from a single borewell on campus.
Vital lesson As an education centre the school can teach its children water management and recycling on campus itself, thus creating a water-literate citizenry.
It is with such examples that a city like Bangalore can not only supplement its water requirements but also become a water-wise city. All schools and colleges all across the country can learn from Buddhi School and get water wisdom.
