Contaminated TG Halli reservoir threatens Yettinahole project benefits

Bengaluru: Residents of Bengaluru may lose out on the benefits of the Yettinahole drinking water project unless water in Tippagondanahalli (TG Halli) reservoir is made potable.
The department of forest and environment is set to issue notice to Bengaluru Water Supply and Sewerage Board (BWSSB) to stop sewage from entering the reservoir.
"The solution is to stop inflow of sewage.said Eshwar Khandre, minister for forests and environment. "We will issue a notice to BWSSB through Karnataka State Pollution Control Board."
The Yettinahole project, which had its first phase inaugurated on Sept 6, aims to deliver 1.7tmcft of water to TG Halli by 2027, supplying 20 million litres per day (MLD) of drinking water to Bengaluru. But the forest department raised concerns over industrial effluents and residential sewage flowing into the reservoir. Khandre insisted that the water should not be used for drinking until it is rendered potable.
Last week, Khandre wrote to chief minister Siddaramaiah, asking him to convene a meeting with ministers for water resources and minor irrigation to discuss cleaning TG Halli and other lakes in Bengaluru. And until the water is clean, he urged the govt to permit BWSSB to sell treated water from these lakes to the construction and industrial sectors. Officials indicated that the matter will likely be addressed during the cabinet meeting next week.
"The department's concern is valid. We are working to expedite acquisition of forest land to complete the Yettinahole project by 2027, but it's the BWSSB's responsibility to ensure TG Halli reservoir is prepared to receive and supply clean drinking water," said a senior official from the water resources department.
BWSSB officials, meanwhile, claimed water in TG Halli is already being treated through advanced processes. In a positive development, water from TG Halli is being blended with Cauvery river water at a 1:20 ratio and supplied to Bengaluru for drinking. The blended water, released to the ground-level reservoir (GLR) at Hegganahalli last week, has been certified as safe by Indian Standards of Scientific Certification (ISSc).
"The water is clean enough for consumption. Sewage is diluted before reaching the sewage treatment plant (STP), and the water undergoes ozonisation and chlorination at the plant. TG Halli will be able to supply 110 MLD of drinking water by the time Yettinahole water is released to the reservoir," said a senior BWSSB official.