Lakes filled with treated water may lead to floods as monsoon arrives, caution activists
With the monsoon having set in, lake conservation activists and experts in the city have raised concerns over several lakes being filled with treated water
With the monsoon having set in, lake conservation activists and experts in the city have raised concerns over several lakes being filled with treated water, warning that this could lead to flooding in some areas. As part of an effort to improve groundwater levels in the city following the severe water shortage in summer 2024, the Bangalore Water Supply and Sewerage Board (BWSSB) has been filling many lakes with secondary treated water. So far, BWSSB has filled 23 lakes, including the ones in Kengeri, Ullal, Madavara, Herohalli, Jakkur, Rachenahalli and Allalasandra. Work is on to fill another 40 lakes, including Hebbal, Nagavara, Doddabidarakallu, Mahadevapura, Sheelavanta and Sadaramangala.
No sluice gates Activists have cautioned that filling lakes in the city to the brim with treated water could create problems as rains arrive. “This has compromised their water retention capacity. There is no space for the incoming rainwater. Moreover, none of these lakes have sluice gates for authorities to manage water levels as rainwater comes into these lakes. This could potentially lead to local flooding. Even if the monsoon is weak, there could be very heavy rainfall events as seen in previous years, which we should be ready for,” said V. Ramprasad, president of the Federation of Bengaluru Lakes. Raghavendra Pachapure, a resident of Kengeri associated with ActionAid, an NGO, said many lakes, including Kengeri lake, were filled through the year, against their natural cycle.
“Most of the lakes in the city dry up in summer, when desilting works used to be carried out, and then fill up again during the monsoon. We have started thinking about these lakes in a very human-centric way and seeing them as instruments for groundwater recharge. We have converted them into something like overhead tanks, but on the ground. This is not good for the biodiversity of these lakes,” he said, pointing to the seasonal cycle of lakes. Plan on paper When former Chief Minister Basavaraj Bommai held charge of Bengaluru Development portfolio, he earmarked ₹35 crore for sluice gates at lakes following floods in Mahadevapura and K.R. Puram in 2022.
However, the project did not take off. Eventually, the erstwhile Bruhat Bengaluru Mahanagara Palike (BBMP) prepared a detailed project report (DPR) in 2023 to install sluice gates at 102 lakes, but the project again did not take off. A senior civic official said sluice gates would be installed as part of the climate resilience project taken up with funds from the World Bank loan. He also said a gradient is being maintained between the inlet and outlet and that this would prevent flooding.
The BriefWire