In the Capital, the Delhi Jal Board (DJB) is not far behind. With the monsoons scheduled to arrive anytime now, DJB has recently set up an `Assistance cell' for rain water harvesting. The cell consists of 5-6 engineers who give the necessary technical information about water harvesting. What is more, DJB is also planning an awareness drive. The awareness drive, says an official of DJB, is aimed at making people, more aware of the need of water harvesting and the benefits of it. Leaflets, booklets and posters have been printed in English as well as Hindi.

Rooftop rainwater harvesting, a simple, economical and eco-friendly method of water harvesting, could be the ideal solution for a place like Delhi which has its water resources shrinking, every season. Its pre-independence population of 17 lakh, reached a whooping 135 lakh in 1999. Estimates suggest that if the entire rooftop area of Delhi (approximately 140 sq km) is utilised for rainwater harvesting, the expected rise in groundwater level due to additional recharging of ground water would be 0.5 mt. One can capture and recharge about 65,000 litres of rainwater in Delhi from a 100 sq mt rooftop and meet the drinking and domestic needs of a family of four, for 160 days.

A number of examples are already quoted. Artificial recharging through four check dams in Jawaharlal Nehru University (JNU ) and Indian Institute of Technology (IIT) Delhi have met with success. Storage of 4.60 to 22.18 thousand cubic meter has created raises water level by 0.8 to 0.9m. Not just this, Mehsana, in Gujarat, Amravati in Maharashtra, Odakkali in Kerala and Kolar in Karnataka have also spun success stories.

A booklet on rainwater harvesting released by Confederation of Indian Industry (CII) and the Central Ground Water Board in May 2000 has even estimated the cost of water harvesting. The cost of rainwater harvesting structures for a 200 sq mt rooftop or pavement area may vary from Rs 800- Rs 2,000. This estimate is based on the assumption that wells or boreholes are available in the dwelling unit, which can be used for recharging the rainwater.

However, Delhi still has a lot of learning to do. While the district administration in Dewas (Madhya Pradesh), has made rainwater harvesting mandatory for all houses having tubewells, and Chennai Metro Water Board has made rooftop rainwater harvesting mandatory under the city's building regulations, Delhi government's announcement about making water harvesting compulsory "is still to be discussed in the cabinet", according to a minister in the Delhi government. At this rate, this monsoon session could again go waste.