The bye-law that the BWSSB has devised for rainwater harvesting is simple to understand. A look by S. Vishwanath

As the December 31 deadline for implementing rainwater harvesting system in Bangalore comes close there is an upsurge in queries for its design and implementation. The rainwater theme park (080-26653666) set up by the BWSSB, the first of its kind in India, provides valuable assistance to the citizen who is interested in knowing more about the law as well as implementing it.

Bangalore as a city has gone through several epochs of water dependence. Till about the year 1895, it was the local wells and tanks that provided water. From 1895 till 1972, the Arkavathy provided water to the city from the reservoirs at Hessarghatta and T.G.Halli. From 1972, the source shifted to the Cauvery. Unfortunately it also meant that as new sources of water were developed the old sources were neglected and given up. These ecological systems have fallen into disrepair.

An exploding demand through an increasing population and changing lifestyle means that the waters from the Cauvery and the lakhs of borewells drilled in the city are not enough. Tanks and lakes have to be revived as they are being done slowly and at an excruciating pace. The Arkavathy system too is under revival and committees have been appointed to search for fresh water sources.

In the meantime the city blessed with an average rainfall of 970 mm annually can supplement its water through rainwater harvesting. The process involves either storing the water in the sump tanks or recharging the aquifer through recharge wells and borewells. A small 30 x 50 site is endowed with nearly 140,000 litres of rainwater annually. The site can best make use of this water by collecting it or recharging it.

Thankfully the city has a large number of pro-active people who have done some work in this regard that is personally benefitting and a service to the community. Open wells have sprung back to life and rainwater in sumps have lasted for six months as supplementary water in many homes.

What is expected

Bye-law: The bye-law which the BWSSB has devised is the most simple to understand. All it says is that one needs to create a 20-litre storage or recharge system for every square metre of roof area. So, if a house has a roof area of 100 square metres then it needs to have storage or recharge system of 2,000 litres. For paved areas on site other than the roof, the number is 10 litres. If a recharge system is made it should be in the form of a well with a minimum depth of three metres. This is to ensure good percolation of the water. Connections can be made to the existing sump, existing open wells or even existing borewells. There is no mandate that filters need to be used. The choice is left to the owner.

Livelihood: Ramakrishnappa is from the village of Kuruburakunte. He has over the last 10 years designed and implemented many rainwater harvesting structures starting with his own house in the village and then building them for government schools. Now he provides assistance to many homes and apartments in Bangalore to implement rainwater harvesting systems. This has resulted not only in benefits for the buildings but also has provided a livelihood to him.

Muniyappa is from the Bhovi community, whose members are traditional well-diggers without jobs because well digging was abandoned by the city. Now with the recharge wells for rainwater harvesting being done all across the city he has dug more than 1,000 of them and is able to feed his family and educate his children.

Rainwater harvesting has both personal and community benefits. It also has ecological and social benefits. From the era of tanks and lakes, to the era of rivers and finally to the era of rainwater harvesting. This is the city's move to satisfy its thirst.

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