Delhi Constructs More Rainwater Harvesting Pits

The New Delhi Public Works Department has announced that it has constructed an additional 82 rainwater harvesting pits to capture water during the monsoon and recharge aquifers. The pits were constructed at waterlogging hotspots in the city along the margins of roads to prevent waterlogging.  The Delhi administration made the installation of rainwater harvesting systems mandatory in 2012 for all plots exceeding an area of 100 m². Although the aim was to complete 1,500 such pits in partnership with roads authorities and civil agencies by July last year, there are currently just over 1,000 pits in place.

This development is line with the policy of central government from 2012, which contains provisions for rainwater harvesting - including the revival of traditional water harvesting structures by States – but also seek to increase the availability of utilizable water in urban and industrial areas and the conjunctive use of groundwater and rainwater.

The rainwater harvesting systems in New Delhi are also mandatory for buildings whose water discharge during rains can exceed 10,000 litres per day. All landowners complying with this regulation are provided with a 10% rebate on their water bills, and those not complying can face additional water charges of up to 50%. Furthermore, new water connections to households are only approved if the building plans include a rainwater harvesting system that complies with government regulations.

In May, the government ordered a survey of suitable rainwater harvesting sites, which involved 2,139 municipal buildings, health centres, parks and roads. It weas found that a rainwater harvesting system already existed on the majority of the sites: some 63% of the sites (1,341 sites in total) has a system in place, of which 96% were functional.     

New Delhi has a low rainfall, only receiving 611 mm of precipitation on average a year, which falls on between 20-30 days a year between June and September. The city requires some 477,000m³ of water per day to satisfy the demand of the population of 21 million. However, the water board currently only has some 354,00 m³ available. This water is largely supplied through a lined canal from the Yamuna River at Haryana, but the city administration has requested a larger share and allocation of water and has petitioned the Delhi High Court over its water supplies, also citing poor quality of the raw water being supplied to it which contains high levels of ammonia. It is in the context of this shortfall in supply that the Delhi government announced a number of measures to respond to this water supply shortfall, of which rainwater harvesting was one.