New Delhi, June 15, 2012: Thrust upon the government as a court order in 2001, rainwater harvesting has been a failure in Delhi. Recently chief minister Sheila Dikshit also accepted that the policy has not managed to achieve the desired results. Essential for a city like Delhi that is largely dependant on neighbouring states for its water supply, rainwater harvesting can be successful if adopted uniformly and on a large scale.
Delhi, June 14, 2012: How much is 69 billion litres of water? By a rough calculation it is equivalent to nearly 9 million water tankers — the same ones that can be seen trundling about supplying precious water to Delhiites in a swathe of residential colonies.
But, 69 billion litres of water is the amount of water that rains on Delhi's rooftops every year. The calculation is simple — take Delhi's average rainfall at about 490 millimetres, and multiply it with the total rooftop area of about 140 square kilometres as estimated by some experts.
Evaluation of the Rooftop Rainwater Harvesting Project.
Source : UNICEF