The Government of Tamil Nadu is encouraging rainwater harvesting in the Statte since the past few years. This page gives the basics of rainwater harvesting.
"An old technology is gaining popularity in a new way. Rain water harvesting is enjoying a renaissance of sorts in the world, but it traces its history to biblical times. Extensive rain water harvesting apparatus existed 4000 years ago in the Palestine and Greece. In ancient Rome, residences were built with individual cisterns and paved courtyards to capture rain water to augment water from city's aqueducts. As early as the third millennium BC, farming communities in Baluchistan and Kutch impounded rain water and used it for irrigation dams."
I am a consultant on technology transfer for rural areas. Please visit www.grameenbharat.in for more details......read more