Rainwater harvesting necessary to meet city's water needs: Delhi Jal Board

New Delhi : Delhi's increasing water demands can be met only if civic bodies and public authorities implement rainwater harvesting and substitute groundwater with treated waste water for non-potable purposes like irrigation, horticulture and sanitation, the jal board told the Delhi High Court.

In an affidavit placed before a bench of Chief Justice D N Patel and Justice C Hari Shankar, the Delhi Jal Board (DJB) has said that the current water requirement of the national capital was 1,140 million gallons per day (MGD), of which 935 MGD came from groundwater and sources like raw water from the Yamuna river.

By 2021, the city's demand for water would increase to 1,380 MGD and with groundwater sources in Delhi already over-stressed, there was a need to explore alternate means like rainwater harvesting (RWH) to meet the capital's requirements, the DJB has told the court.

The Board also said that systems like RWH and using treated waste-water for non-potable purposes would also relieve the stress on groundwater and would help to recharge it. Towards this goal, the DJB has suggested that local authorities like the municipal bodies and the Delhi Development Authority (DDA) should strictly enforce the modified building bye-laws according to which RWH system is mandatory for a plot size of 100 square yards or more in order to get a building plan sanctioned and obtain a completion certificate.

Apart from that, the Board has also suggested that the public authorities, including the Public Works Department (PWD) and the Irrigation department, and other park owning agencies ought to "substitute use of groundwater with adequately treated waste water for horticulture and gardening".

The DJB's suggestions came in a PIL initiated by the court on its own after coming across news reports on alleged failure of the Delhi government and other public authorities to check the depleting groundwater levels in the national capital.