Summer scorcher: Falling water level in Bengaluru's Sankey tank

Bengaluru: The prolonged heatwaves that the city is enduring have dealt a blow to the water bodies in the city, particularly to rain-fed lakes such as Sankey Tank in Malleswaram.

Dr T V Ramachandra, coordinator of the Energy and Wetlands Research Group at the Indian Institute of Science (IISc), Bengaluru, cited rapid surface-level evaporation due to the heat and the absence of rain as two major reasons for the declining water levels. He also pointed to a combination of several short-term and long-term issues exacerbating the situation.

“There is no water inflow anymore. The neighbourhoods around the lake are overexploiting the groundwater table by digging borewells. In the name of lake rejuvenation, there is rampant concretisation around the lake, due to which, the ecosystem integrity is lost,” he said.

He added that the authorities’ refusal to restore the surface fountains is also leading to rising nutrient levels in the water. The fountains would have facilitated aeration or the even distribution of oxygen in the water.

Preeti Sunderajan from the citizens’ group Citizens for Sankey highlighted the officials’ apathy.

“We have tried to highlight the problems with fixing concrete walkways and planting non-native trees such as palm around the lake but the authorities only tell us that it has been done in consultation with the Karnataka Tank Conservation and Development Authority (KTCDA). I don’t think any ecologists or environment experts were present in these discussions,” she said.

A senior official from the BBMP lake wing denied these allegations, asserting that all lake-related work has been based on expert opinions from the KTCDA and residents’ approvals.

“The concreting is very minimal around the lake. This does not impact the water-holding capacity of the lake,” he said.

He acknowledged there were “no solutions” for the receding water levels other than waiting for the rains.

However, an engineer from the Bangalore Water Supply and Sewerage Board (BWSSB) mentioned that if residents or BBMP authorities propose, the lake could be filled with treated water. They could supply this water in tankers from the sewage treatment plant in Hebbal.