Restoration of 12 lakes begins but silt won't be removed fully

Two years after firming up plans to restore 36 polluted lakes, the BBMP has finally started the work on 12 of them. But one thing is already ruled out: the silt in the lakes will not be fully removed because of the challenges in its disposal.

Authorities are set to award the contract for the development of Mallattahalli Lake (Rs 19.07 crore), Hulimavu Lake (Rs 4.35 crore) and Arakere Lake (Rs 2.6 crore).

In addition, plans have been drawn up to develop Doddagubbi Lake (Rs 11 crore), Chikkagubbi Lake, Yerrappanahalli Lake and Kadusonnappanahalli Lake (Rs 14 crore), Gangashetty Lake (Rs 4 crore), Horamavu Lake (Rs 4 crore), Garudacharapalya or Goshala Lake (Rs 3 crore), Sarakki Lake (Rs 5 crore) and Vagaiahana Lake in KR Puram (Rs 2 crore).

The plan to restore 36 lakes was drawn up two years ago but getting it approved by the Karnataka Tank Conservation and Development Authority took time because the pandemic disrupted the schedules, said BBMP Chief Engineer (Lakes) B T Mohan Krishna.

For now, the restoration will start with 12 lakes but there will no complete desilting. "We are not trying to restore the original tank capacity as lifting so much of silt will bring up problems associated with disposal. The focus of the restoration is to safeguard the lake biodiversity and increase the potential for groundwater recharge," Krishna said. "The lakes are not meant for irrigation."

As per the plan, the works will be awarded in the next two months with a one-year deadline. Constructing the embankment wall and ring bund, and removing the top layer of silt will be some of the major works. The desilting will be limited to a depth of 0.6-1 metre so that only the top layer (flesh), which usually contains pollutants like sewage, is removed.

'No heavy metals found'

Krishna said no heavy metal was found in any of the 36 lakes. "Still, after the dewatering process, silt samples will be collected from each lake and sent to two NABL-accredited labs. If any contamination is found, the soil will not be allowed to be disposed elsewhere," he said.

Chief Minister B S Yediyurappa is monitoring the restoration of 25 of the 36 lakes under the Vision 2022 programme and more lakes will join the list soon. For now, the BBMP is using the funds allocated previously.