BENGALURU: The state government’s investment of Rs 230 crore to revive the Thippagondanahalli (TG Halli) reservoir in west of Bengaluru is soon likely to go waste. This is because supply of 20MLD (million litres per day) from the reservoir has now been completely stopped, and the government is focusing on utilising water from the river Cauvery to the optimum.
After a long gap, Bengaluru Water Supply and Sewerage Board (BWSSB) had started supplying water from the reservoir to parts of Bengaluru. In 2023, water supply had resumed and 30MLD water was being drawn from TG Halli to supply water to most parts of west and south Bengaluru. This reduced to 20MLD in 2024 and 2025 and has now stopped.
“No water is being supplied from TG Halli reservoir since 2025. After nearly all areas of Bengaluru were covered under Cauvery 5th Stage project, supply from TG Halli was stopped,” a senior BWSSB official said. At present, BWSSB supplies 1,850MLD water to Bengaluru under Cauvery 5th Stage.
A detailed project report to supply water under Cauvery 6th Stage is being prepared to supply an additional 500MLD by 2028. The cabinet also approved the project in February, which will cost Rs 6,939crore.
“Three years ago, Rs 230crore was spent on installing new machinery and repairing existing ones. A new ozonization plant was also installed to ensure quality water supply. When supply from TG Halli was started, it was decided to supply in a ratio of 1:10 (1MLD of TG Halli water with 10MLD of Cauvery water). The plan was also to revive the Arkavathi river to ensure continuous supply of water. But we don’t have the exact ground flow map of the river to revive it,” the official admitted. “We don’t know what will happen with TG Halli after some time.
There are no plans to use the water or make it a tourist site. There is 2.1tmcft of rainwater in the reservoir. A couple of years ago, it was filled to its capacity of 3.15tmcft. The standing water is helping crops and recharging groundwater in the vicinity.” TG Halli reservoir was constructed in 1933, across the Arkavathi river, downstream of Hesaraghatta reservoir, 26km west of Bengaluru. Under the first phase of the project, 28MLD was being supplied and was later expanded to 149MLD. Supply started deteriorating from 1988 due to poor monsoon, as per BWSSB data.
Experts say there is no need to draw water from Mekedatu or Yettinahole if TG Halli is revived and utilised to the fullest. Minor Irrigation department officials said survey and ground investigation is being done in Cauvery Wildlife Sanctuary for constructing a balancing reservoir at a cost of Rs 9,000crore to hold 67.16tmcft water, of which 4.75tmcft will be supplied to Bengaluru.
However, forest department officials said no application seeking environmental or forest clearance has been filed. Damage to forest and wildlife has not been done by the authorities. The Mekedatu project will immediately affect around 1,500 families in three villages around the forest -- Hoggaduddi, Bommasandra and Muttatti.
Prof TV Ramachandra, from the Centre for Ecological Sciences, IISc, has opposed the Mekedatu and Yettinahole projects. He said there is no need to bring water from so far to Bengaluru, which receives good rainfall. If rainwater harvesting is efficient and existing infrastructure is utilised, there is no need for anything else, he added.