Several lakes in the city that were either rejuvenated or usually well maintained have developed untreated sewage and effluent inlets. Walkers who observed the change have expressed concern about the health of the lakes. Some of the affected ones are Allalasandra, Jakkur, and Rachenahalli lakes in north Bengaluru, which were all rejuvenated. In east Bengaluru, Ulsoor lake has developed inlets, while residents have reported uncleared algae in Sankey Tank, which emanates foul smell.
Allalasandra lake
The northwest corner of Allalasandra lake at Yelahanka has an inlet of black brackish water that has turned a breeding ground for mosquitoes. This despite the lake having a dedicated sewage treatment plant. “The source of this inlet is the improperly treated effluents from the nearby KMF Dairy,” claimed S. Vishwanath, water conversation activist from the area.
The diary has an effluent treatment plant (ETP) as well, but the inlet has been traced back to KMF and it smells of milk products that has gone sour, residents said. Rakesh Singh, managing director of the KMF, said he would send officers to the lake at the earliest and correct the ETP if the inlet was found to be from the dairy.
Jakkur, Rachenahalli lakes
The nearby Jakkur and Rachenahalli lakes have also developed similar issues. While BBMP Lake division officials claim they have diverted the sewage inlet away from Jakkur lake, residents and activists said the problem persists. “The BWSSB has laid a new underground drainage pipeline at Sriramapura and other areas behind the Jakkur lake. This UGD line is yet to be connected to the STP. Sewage often overflows into the storm-water drain (SWD) and enters the lake. The BWSSB needs to fix this,” said V. Ramprasad, convener, Friends of Lakes. He added that overflow from Jakkur lake also enters Rachenahalli lake, and walkers in the park next to the lake have reported foul smell emanating from the waterbody.
Sankey Tank
What is also a cause for concern is Sankey Tank, one of the most well-maintained lakes in the city, seems to have developed problems. “Sometimes, there is brackish water. We get a foul smell near the swimming pool end of the lake,” said Anand A.R., of Sankey Tank Walkers’ Association.
A BBMP official explained that the source of the odour was uncleared dead algae that emanates methane. The lake has no sewage inlet at all. However, SWDs in the surrounding areas have for the first time been connected to the lake and some overflow may be from the drains, activists said.
Garbage at Ulsoor lake
A portion of Ulsoor lake that is covered with weeds.
At Ulsoor lake, it is illegal dumping of garbage that is causing a problem.
“We have diverted sewage, but residents along the catchment area regularly dump garbage, including wet and meat waste, into the SWD. When it rains, the garbage floods the lake bed and settles on the wetland. After a spell of rain, we get over 300 loads of garbage, which leads to growth of algae,” said a senior BBMP official in charge of the upkeep of the lake.
Mr. Ramprasad said unless the civic agencies remain vigilant and monitor sewage inlets, rejuvenation efforts would amount to nothing if a lake’s health was compromised.
