Raintapping
The reality of Chennai's dependence on rain is not fully appreciated. If it were, then rainwater harvesting (rwh) would have been looked upon as a social obligation. Considering the annual average rainfall of 1,280 millimetre in the city area of 174 sq km, the annual rainwater harvesting potential is about 222 billion litres, which means 608 mld. The city's water demand is 880 MLD. There are two aspects of RWH: lakes in the open areas and rooftops in built up areas.
Rooftop-spin
After the severe drought of 1992 and 1993, Metro Water began a actively promote RWH. It worked out a