Can a dying lake be restored to a self-sustaining entity without the use of concrete or chemical? The Maragondanahalli lake in Electronic City phase 2 in Bengaluru is perhaps the first ecologically restored lake that can give a lesson or two on cost-effective restoration where 10 floating wetlands were created to naturally treat the sewage water entering the lake.
The project, a CSR initiative of the JSW Foundation and implemented by Malligavad Foundation at 1.7 crore, has restored the 21-acre lake that had been reduced to a dump yard filled with sewage, sludge, debris and city waste in a low-cost and self-sustaining way as it does not rely on power-consuming sewage treatment plant. It has given the goby to the usual concrete walkways, jogging tracks, amphitheatres or the flashy LED lights that damage the natural lake ecosystem.
"When we decided to restore the lake, it had thick hyacinth growth indicating the lake was highly polluted and no longer had any marine life due to eutrophication. We chose an 800-year-old technique of floating wetlands to restore the lake, which is a hydroponics concept," said Anand Malligavad, a techie-turned-lake conservationist who runs the Malligavad Foundation.
The Maragondanahalli lake is divided into two areas - 15 per cent of the area is a natural sewage treatment area (comprising 10 floating wetlands) and the remaining 85 per cent, a reserve for collecting fresh rainwater.
"These two areas have been separated by an earthen bund created using sludge and silt excavated from the lake. This works like an impervious mix that can be used to plaster the bund," said Malligavad adding that the water storage capacity of the lake had been enhanced by one lakh cubic metres and was now a recharging source for the borewells.
The floating wetlands were created by growing 12,000 canna and vetiver plants, whose roots act as natural purifiers by absorbing toxins and pollutants. The local community volunteered to plant 4,500 saplings of native species in and around the lake, which has transformed into a natural recreational zone that is attracting birds like wire-tailed swallows, green bee-eaters, scaly-breasted munia and nearly 20,000 people during the weekends.
P.K. Murugan, president of JSW Steel Vijayanagar & Salem Works said, "Karnataka is a strategically important state for the JSW Group, which is a US$ 22 billion company operating across 14 states. The restoration of Margondanahalli lake is a step to give back to the community. While we have several ongoing projects (under CSR), this one is outside of our direct impact zones. Two years back, we decided to take up the unique lake restoration project during an interaction with Anand, who showed us photographs and videos of the lake. Today, I am happy to see the transformation of the lake."
Ashwini Saxena, CEO of JSW Foundation who handed over the restored lake to the community on Monday said, "As a corporate citizen, we realise that water always manifests as a challenge whether it is scarce or abundant. So we need to figure out a very contextually relevant way of treating water and working with water. In Maragondanahalli, the restoration has ensured the lake rejuvenates itself without much human intervention."
"Maragondanahalli lake is one of the 12 lakes along the 48-km stretch that connects Shikaripalya to Pennar river. The project should encourage local communities to take up the natural rejuvenation of the water bodies. Mindless dumping of city waste and diverting sewage into Pennar river is not a solution as the vegetables reaching the Bengaluru market from Hosur and Shoolagiri are grown using the highly polluted and toxic river water," cautions Malligavad.