BBMP to build sewage diversion drains near four RR Nagar lakes

The BBMP is all set to build sewage diversion drains near four lakes in RR Nagar Zone at an estimated cost of Rs 50.34 crore.

Funds for the project have been taken from the sums earmarked to set up pre-processing plants near scientific landfills.

The Urban Development Department (UDD) last week gave its consent for the project by slashing the tender rates quoted by the lowest bidders.

The construction of sewage diversion drains near lakes is a new phenomenon in Bengaluru to arrest the flow of sewage into the waterbodies constantly fed with contaminated water. The success rate of these projects is, however, very low as the sewage gets mixed with rainwater whenever the flow is high.

CAG report

A recent report by the Comptroller and Auditor General of India (CAG) highlighted entry of sewage into lakes where concrete structures have come up.

As per the official document accessed by DH, bidders had quoted more than 10% the estimated cost of the BBMP in each of the three projects. Following the government’s order to cap tender premium, the UDD negotiated with the bidders to reduce the tender cost to less than five per cent.

The four lakes where the project is expected along with the final project cost are: Mallathahalli Lake (Rs 19.89 crore), Srigandhakaval Lake (Rs 20.34 crore, including development of the lake), and Hosakerehalli Lake and Kenchenahalli Lake (Rs 10.11 crore) of RR Nagar Zone.

While K Damodar and Co has bagged works at two lakes, Nadimpalli Purushotham Raju (NPR Infratech) has won the work of Hosakerehalli and Kenchenahalli lakes.

The UDD has directed the BBMP to engage a third-party quality-monitoring agency to keep a check on the works.

V Ramprasad, convener of citizens’ volunteer group Friends of Lakes (FoL), said the sewage diversion drains are of no use during the monsoon season.

“In lakes where such structures have been already built, the diversion drains are able to stop sewage entering into the lakes when the flow of water is slow,” Ramprasad said.

“If there is a heavy flow of rainwater, the sewage gets mixed and enters into the lake,” he said, urging the civic body to focus on stopping the discharge of sewage into the drain.

“The drains are meant to carry only rainwater but most of these canals continue to carry sewage. The authorities must levy heavy penalty on those who connect sewage pipes into the drain in a big way,” Ramprasad added.