Water supply to city suspended after pipeline damaged

KWSB blames KESC for damage while insiders say that it was due to a lack of channelisation.

KARACHI:

The water board is still repairing a large pipeline that was damaged on Tuesday. Since then at least 72 million gallons per hour of water, that could approximately fill 130 Olympic swimming pools, has not been supplied to Karachi.

The Karachi Water and Sewerage Board (KWSB) blames the Karachi Electric Supply Company (KESC) because the pipeline broke down during unannounced load-shedding. The pipeline, which was still being repaired by Sunday, was damaged one kilometre away from the Dhabeji Pumping Station. It took three hours to start pumping water back into the city from an alternative system.

The Express Tribune was told that load-shedding created a vacuum inside the pipeline but the negligence of the KWSB’s officials deployed at Dhabeji was also part of the problem. The water officials channelled water into the pipeline too fast, as a result of which it rushed into the vacuum that had formed inside and burst the pipe. Gallons of water were wasted and the city was entirely cut off.

“KESC is at fault because they cut off the electricity supply without giving us notice, and so when the electricity supply resumed, it produced a shock in the pipeline which it could not bear and consequently it burst,” explained KWSB’s chief engineer Zaheer Abbas Zaidi.

Damaged line

Experts on the bulk water supply told The Express Tribune that the main pipeline carries water 220 feet uphill from Dhabeji. The purpose of the pump is to push water from the major canal to the top of the hill, from where it is supplied to the city.

Due to the suspended power supply, a vacuum was created in the pipeline. It is a rule of thumb that in such a situation, only a minimal amount of water is pushed into the pipeline. This amount of water is then increased gradually. This process is called ‘channelisation’. The KWSB officials and engineers at Dhabeji neglected to do this and pushed in volumes of water that the pipe could not handle

Published in The Express Tribune, July 4^th, 2011.