Rainwater harvesting system is collection of rainwater from the surface which directly receives rainfall. It can be a paved area like a terrace or courtyard of a building, or an unpaved area like a lawn or open ground.
Following links helps to understand what is rainwater harvesting and how to implement them successfully in your apartment.
http://www.reddit.com/r/reddit.com/comments/avm9y/rainwater_harvesting_an_efficient_water_solution/
who invented rainwater harvesting
by rainwater harvesting
Aims and objectives of water harvesting
Stephen K. Booth has written: 'Rainwater harvesting' -- subject(s): Water harvesting, Rainwater
drain and rooftop
picture of rain water harvesting model
by rainwater harvesting
haryana
Aby Emmanuel
because i also do not now
Uttarakhand