To encourage residents to instal rooftop rainwater harvesting systems, the Delhi Government will provide financial assistance of Rs 50,000 and a rebate of ten per cent on water bills.

Delhi Water Minister and Chairman of the Delhi Jal Board (DJB),  Satyendar Jain, convened a meeting with officials and took stock of the progress of the work of installation of Rooftop Rainwater Harvesting Systems.

The Aam Aadmi Party (AAP) Government has also extended the last date for the compulsory implementation of the rooftop Rainwater Harvesting (RWH) system until December 31, 2021.

Interestingly, in order to increase the groundwater levels, the Delhi Government has followed the INLINE-RWH, popularly known as the Dungarpur model.

This model is also known as the INLINE Rainwater Harvesting (RWH) system. This model is cost effective and is being implemented in the tribal-dominated Dungarpur district of Rajasthan.

Jain said, “This model uses innovative techniques and is centred on routing the rainwater directly to a borewell, instead of a regular rainwater-harvesting pit.”

In this system, the rainwater gets filtered within the pipe, removing any need for an additional filter system and harvesting pit. The INLINE-RWH comprises a pipe filter installed horizontally in the rainwater pipe. This pipe is then connected to non-functional and defunct borewells. The filter media of the INLINE-RWH has a Geotextile membrane as a cover, at the mouth of the rainwater pipe. This is followed by wire mesh at the entry point of the different media. This includes coarse sand, gravel/stone aggregate, gravel/stone aggregate. The total length of the filter media is around 90 cm. Another advantage of this model is that it is much cheaper than the conventional ones. “The reason for this system to be cost-effective is that it does not require a heavy installation set-up. While conventional RWH system set-up requires Rs. 75,000 to Rs. 1 Lakh, the INLINE-RWH system can be set up at a cost as little as Rs. 16,000.”

The Delhi Government has also relaxed the compliance norms wherein people can get adequacy certificates for installing the RWH system from architects registered with the Council of Architecture instead of the DJB only the guidelines issued by the DJB have to be followed.