BWSSB awaits water from Yettinahole to sustain TG Halli reservoir

Bengaluru: The Bangalore Water Supply and Sewerage Board (BWSSB), which is awaiting the supply of water from Yettinahole to the Thippagondanahalli (TG Halli) reservoir, is struggling to keep the newly rejuvenated reservoir in good condition.

The BWSSB, in 2019, began the work of rejuvenating the TG Halli reservoir, which had turned defunct. Though the project was completed in 2024 after missing multiple deadlines, the delay in receiving water from Yettinahole has forced the BWSSB to dilute the water at the reservoir with Cauvery water in a 1:20 ratio and pump it out.

“The decision was taken after consultation with the Indian Institute of Science (IISc). It is important that we keep the plant operational and hence the decision was taken,” said Dr Ramprasat Manohar V, Chairman, BWSSB.

While there were, initially, concerns over the quality of water, Manohar said that the IISc had approved the project and the water quality was tested to ensure it is up to the mark.

Senior BWSSB officials noted that many of the machines were imported and keeping them idle for a long time could render them defective. “Many of the pieces of equipment could corrode, and we may have to repair many others if they are left unused for a long time. Hence, leaving them idle is not a good idea,” a senior official said.

While this could act as a stop-gap arrangement, officials hope that the water flow from Yettinahole will start soon to ensure the revival efforts are not wasted.

Ozonation technology

For the first time, the BWSSB has deployed ozonation technology at the reservoir, suspecting that a few settlements around Arkavathy could pollute water at the TG Halli reservoir.

During ozonation, ozone (O3) is infused into the water with the help of a high-voltage current. This clears the water of any bacteria or viruses, thus disinfecting it in the process.

The reservoir is expected to receive 1.7 TMC of water from Yettinahole and will allow the BWSSB to pump 110 MLD of treated water to West Bengaluru. The TG Halli reservoir was one of the major sources of water in the 1970s and had dried up by 2012.