Floating Islands of South Delhi; Hauz Khas Lake Restoration

The Hauz Khas Lake (Tank), a water body located in the middle of one of South Delhi’s most elite watering holes, which has, over the years, consistently been under threat has had yet another lifeline thrown to it.  The lake, a well kept secret from most of the capital’s citizens, probably due to its fluctuating fortunes, has been kept on a lifeline since 2002.

Originally spread over 125 acres with a depth of 4 metres the lake has shrunk in size to only 15 acres and a maximum depth of 1-2.5 metres. This is due to the porous rock bed and heavy evaporation which lead to the lake drying up regularly, and frequently needing attention. In 2002 under the orders of the Delhi High Court to revive the lake, DDA (Delhi Development Authority) implemented a project to divert 2 million litres of treated effluent a day from the Vasant Kunj Sewage Treatment Plant through a natural channel into the lake.

Speaking to Hindustan Times a DDA Official said, “The water in the lakes comes through a sewage treatment plant. It gets polluted in between due to leakages and sewer water entering into the channel.” Effectively polluting the lake with metals, and chemicals which cause formation of a thick layer of nonperishable residue and/or Algae which is harming the water quality and the overall biodiversity of the area.

Thus to rejuvenate, conserve and revive the water body the DDA along with environmental engineer Tarun Nanda have recently undertaken a project. They’ve made use of Floating Wetlands to treat sewage in the drain. These miniature floating wetlands naturally, without the use of any chemicals, purify the water. The plants help in eradicating the algae and absorbing nitrates, phosphate and other heavy metals. The wetlands are themselves a thing of recycled beauty, made using from wire mesh, drainage pipes and used water bottles, with appropriate plants  to filter the water. Currently in the first phase of the project only a few such wetlands have been released into the lake with construction of more underway. These constructed wetlands use phytoremediation and rely on natural processes such as microbes, filtration, absorption and uptake of nutrients into the wetland plants, to purify the lake water.

Besides purifying and clearing the water, the project  will also stop solid waste and sludge from entering the lake. The DDA claims that the cleaning project will be completed in a year and will cost around Rs. 80 Lakhs.

To infuse civic sense and help from the public specifically the locals of the area, workshops are being organised which focus on teaching about the cleaning process as well as participating in the process. “People now come forward to adopt islands. A square metre of floating wetlands cost around Rs 4000-5000. Floating wetlands take less than a day to be made and for funds, we do not depend on the government and are raised through conducting training sessions on how to construct the islands. A training fee of Rs. 500 per person is charged besides collecting donations through the fundraiser Adopt an Island – Haus Khas Lake. The idea is to to also tap CSR funding. Four to five people can together build a wetland,” said Nanda while speaking to the India Water Portal.

Since the project started  in the first week of March, the team have managed to release around 15 such floating wetlands into the main lake with work in progress to release many more by the end of the month and then gradually over the year.

A visit to the lake makes it clear that the biggest challenge will remain the education and better awareness of pollution among the visitors to the area. Plastic trash continues to find its way into the lake waters, thrown by the visitors to the area. The tragedy is that even the many restaurants  in the chic Hauz Khas Village nearby have regularly been on the wrong side of the law for non compliance with basic pollution control norms. Be it waste treatment or disposal. For Delhi’s sake, lets hope that someone sees the opportunity and the benefits from a healthy lake in the area which has some otherwise stunning historical monuments too.

By Ayush Verma

Published on: Mar 31, 2018