Groundwater levels up in some colonies (Times Of Times 15 June 2012)

New Delhi: Even as the capital faces an acute shortage of water in some areas and engages in a tug-of-war with bordering states, the monsoon — a major source of natural water — is round the corner. Though most of the water that comes down as rain is wasted, some colonies in the city have implemented rainwater harvesting systems to raise groundwater levels and, hopefully, improve the supply.

These systems are running successfully in areas like Naraina Vihar, Vasant Vihar, Chittaranjan Park and Mandakini Enclave. A harvesting system captures rainwater from storm drains, the lay of the land and in some cases also rooftops, and transfers it to an underground pit where it passes through filters like gravel, sand, and boulders of different sizes. The purified water then goes through deep, underground pipelines or abandoned tube wells and augments the groundwater levels.

But creating such systems comes with its share of problems, specially bureaucratic hurdles. “Several bodies are involved in the process. While we need permission for creating these structures from the municipal corporations, we also need Delhi Jal Board’s nod to use abandoned tube wells,” says A N Talwar, former chairman of water committee, Vasant Vihar RWA. The area has 26 rainwater harvesting systems in place, but is yet to exploit abandoned tube wells.

“We have identified eight additional sites at parks belonging to the municipal corporation and have been seeking permission,” says Gautam Sen Chaudhuri, spokesperson of EPDP Association, the apex RWA for Chittaranjan Park. The area has five operational rainwater harvesting sites.

Construction of such systems can also cost up to Rs 1.5 lakh, so funding is often a matter of concern. “We are looking at large corporate firms, local councillors, MPs and MLAs,” says Chaudhuri.

Naraina Vihar, which has three operational rainwater harvesting systems, was the first colony to obtain funds from Delhi government’s My Delhi I Care scheme.

“It was a simple process and it got our first system going,” says Satya Prakash, president of Federation of Naraina Vihar Residents’ Welfare Associations.

Apart from the costs of setting up, these systems also require maintenance before every monsoon. “Repair takes about Rs 5,000 for every site. It is important to clean the filters to ensure that water remains pure,” says Talwar.

Problems aside, these systems can go a long way in raising groundwater levels. “There are around 3 lakh tube wells in Delhi, out of which not more than 60,000-70,000 are operational,” says Jyoti Sharma, president, NGO FORCE, which has assisted several localities in implementing rainwater harvesting systems. Their data shows that last year groundwater levels were significantly higher in areas that had rainwater harvesting — water post-monsoon was found at a depth of 29.8 metres in Vasant Vihar, 56.6 metres at Naraina Vihar, and 10.2 metres at CR Park, as compared to 32.5 metres, 58 metres, and 12 metres pre-monsoon .

Apart from raising groundwater levels, one system for collecting rainwater can directly benefit the residents, thereby reducing their dependency on DJB. “Water from rooftops can be used for individual apartments as the process is affordable now,” says P K Ganguly, member, CR Park RWA, adding that it costs only about Rs 5,000 per apartment building.