‘Once it is complete, we will have 2 cr. litres ready for use’

The city’s water supply was disrupted this summer, an incident which officials say will hopefully not recur in the next 20 years. This is due to an urban drinking water supply project that aims to supply water to meet the city’s needs till 2026.

Officials say they hope to complete construction by October and start supplying water before the next summer.

The project has two phases: drawing water from the Karanja, and purifying it and supplying it to the city.

The first phase is the construction of a jackwell near Karanja reservoir, a filter bed near Neelammanahalli tanda and a ground-level reservoir in Naubad. The second phase includes setting up a network of overhead tanks across the city and laying pipes from the Karanja to the city, which will pass through the jackwell and the filter bed.

The jackwell site is 16 m below Karanja reservoir’s lowest level to ensure uninterrupted water flow even during summer. Work on the jackwell is going slowly, as labourers have already hit a rocky layer. “The State government did not allow us to blast the rocks because of the site’s proximity to Karanja reservoir. We are using breakers and a heavy-duty digger to deal with the rocks,” a senior officer said.

The filter bed includes three structures: an aerator, tube filter and sand filter, and a reservoir with two overhead tanks.

Fresh air gets mixed with water at the aerator, impurities are collected at the bottom of the tube filter and water is passed through fine sand to drain out dirt and other small particles. Water purified in this way is stored in the reservoir and the overhead tanks.

A high level of technical proficiency is needed in constructing the filter bed, which accounts for the slow progress of the structure. “We are slow because we are careful, not because we are lazy,” quipped one of the engineers involved in the project.

Deputy Commissioner P.C. Jaffer said: “Work on these structures is 70 per cent complete. Once complete, we will have over 2 crore litres of filtered water, in various tanks and sumps, with which we can pass through harsh summers with little difficulty,” he said.

  • Water will be drawn from the Karanja, purified, and stored in overhead tanks

  • Work on the structures is 70 per cent complete, says Deputy Commissioner