BWSSB eyes Helen, Margarita to revive TG Halli dam

Emboldened by the successful utilisation of the tunnel boring machines — Helen and Margarita — by Bangalore Metro Rail Corporation Limited, now Bangalore Water Supply & Sewerage Board’s plans to utilise them for their nine-year-old project of recharging Tippagondanahalli Reservoir using treated water.

 The project proposes to transport 200 MLD of treated water from Koramangala and Chalaghatta (K&C) Valley’s waste water treatment plant  to Nandi Hills for a distance of nearly 65 km for natural purification. 

The project plans to install four centrifugal pumps from K&C Valley till Nandi Hills where huge pipelines will be laid and BMRCL’s machines can be used.

The proposed plan is to pump 200 mld of treated sewage using centrifugal pumps, each having 50 mld capacity to an elevation of 980 metre into the proposed ground-level reservoir at the foot of the  hills.

According to a BWSWSB official, they are thinking of using the machines. However, a BMRCL official expressed skepticism as they are powerful machines and cannot be used for water projects.

According to the project, treated water would be lifted using booster pumps to identified hill surface facing TG Halli catchment. This will be distributed/sprinkled using distribution system and holding tanks which would naturally be aerated.  

The run off from the hills may be collected in the tank at the foothills and allowed to be used for irrigation through a chain of lakes leading to T G Halli Reservoir.  

There are also plans of using the surplus water reaching T G halli Reservoir to be treated further as the board has plans of upgrading their existing water treatment plant by installing advanced technology.  

This ensures the enhancement of natural water resources and eliminates psychological barriers on usage of treated waste water.

Though the project aims to recharge the reservoir for drinking water supply, it will indirectly encourage farmers to use it for irrigation also. 

Of the 200 mld treated water, it is assumed that about 135 mld will reach the reservoir which could be further supplied to the City.  

The Board official said not only Bangalore but Chickaballapur and surrounding villages also will be benefited. 

The project in 2005 was estimated at the cost of Rs 415 crore, nine years later, the cost has escalated to Rs 500 cores with annual operation and maintenance cost of Rs 80 crore. T G Halli, which was the maiden source of water supply to City was supplying up to 30 mld of water till November 2013. However, the supply was discontinued as water level dropped below minimum levels. 

Increasing urbanisation and industrialisation around the reservoir area had altered drainage pattern affecting the inflow into the reservoir.  

With this project, there is hope that T G Halli may get recharged.