Malfunctioning sewage plant hampers revival of city's only bird reserve

Despite the forest department rejuvenating the Yelahanka Puttenahalli Lake, it would take longer to fully restore the city's only bird conservation reserve due to a rundown sewage treatment plant.

Home to over 127 bird species, the lake was declared a bird conservation reserve in August 2015. But its catchment area has been built over and is mired with sewage. The forest department began rejuvenating the lake in September 2017.  

Forest officials wrote to the Bangalore Water Supply and Sewerage Department to restore the 5-MLD sewage treatment plant and make sure it pumps cleaner water into the lake.

"Besides rainwater, treated water is the only source of rejuvenation for the lake in the dry months," Deputy Conservator of Forest, Bengaluru Rural, Dipika Bajpai told DH. "The existing STP is being used to supply water to the Attur Lake and Allalsandra STP. Now, the BWSSB has a greater responsibility to ensure the Puttenahalli Lake also gets water from this STP."

The lake wears a barren look as the forest department has drained it for desilting. "It was slushy. Water was barely up to the waist level (three feet). We've cleared the silt up to 10 feet and are slanting the base from 0-10 feet, mindful of all the bird species visiting the lake," said an official, in-charge of the lake. The natural depth of the sprawling 37-feet lake would be roughly 12 feet. Its catchment area has been completely constructed. The state government has sanctioned Rs 12 crore for its rejuvenation. The department, however, invited tenders for Rs 9 crore.

"We'll use the remaining funds for beautification at a later stage. Our priority is to rejuvenate the lake, for which we're seeking the BWSSB's help as the dry spell after the monsoon season will be very tough," Dipika said.

Nityanand Kumar, BWSSB chief engineer for waste water management, said estimates are being prepared for the STP, which is getting delayed due to technical issues. The target is to complete it by 2020.

The BWSSB is also building underground sewage lines to ensure dirty water does not enter the lake.