Bengaluru lake has India’s largest floating island

BENGALURU: Once a garbage dump in Electronics City, Hebbagodi Lake has now made it to the Limca Book of Records for having India’s largest floating island. The 12,000-sqft island has strips of vegetation that crisscross the waterbody. It comprises rafts that allow plants to grow hydroponically (without soil, and through mineral nutrient solutions) and act as cleaning agents. The floating rafts are built with reused PVC pipes.
The objective is to improve water quality by removing excess nutrients and maintain the pH level of the water between 6.5 and 8.5 — considered normal.The roots of the plants grown on these rafts have pollutant-digesting microbes that degrade pollutants in the waste water that flows into the lake.

Spread over 35 acres with a 2km perimeter and located in Anekal taluk of Bengaluru Urban district, the lake’s journey back to glory began in August 2016 when biotech major Biocon India and its subsidiary, Syngene International, took up the lake revival project under their corporate social responsibility programme.
The lake has five sewage inlets from residential areas and two stormwater inlets.
1.5km bund built, desilting taken up
Hebbagodi Lake is downstream of Shikaripalya, Tirupalya and Veerasandra lakes and upstream of Kammasandra Lake. In October 2017, Biocon Foundation signed a pact with the state government for lake restoration.
Silt-removing and deweeding operations were taken up on a war footing. The weed was composted to spread green cover around the lake. Energy-efficient cascading aerators were installed to increase the level of dissolved oxygen in water. Underground conduits were laid to address sewage spills and stench. A culvert was constructed to prevent excess sewage flow.
Once the lake was full, a bund was built to augment its water-holding capacity and create a walkway. Over 67,000 cubic metres of soil was used to create a 1.5km bund. “We’ve done whatever we could to rejuvenate it. Now, citizens should maintain it,” said wing commander (retd) GB Athri, who played a major role in the lake’s revival.
More lakes to be revived
Biocon Foundation is now set to take up Kammasandra and Bommasandra lakes. “Our aim is to rejuvenate Kammasandra Lake as it is slightly larger. Other companies should adopt it,” said its managing trustee Kiran Mazumdar-Shaw.
Shaw said Bengaluru had 250 lakes in 1960, and just 34 now. “The government must ensure more lakes are revived. All stakeholders, including citizens, politicians and government officials, must start taking ownership of the lakes,” she said.