About 20 workers engaged by the Tamil Water Supply and Drainage (TWAD) Board worked continuously since Thursday afternoon to dig out the pipe that burst under heavy pressure.
A power trip and the consequent forceful backflow caused a 15 ft breach in the line. Water board officials said on Friday that uninterrupted excavation helped in reaching the damaged line that lay about 10 ft below. Mercifully, there was no rain, said an official overseeing that work at the burst spot, a little more than a kilometre from the pumping station at Velliyankadu.
The line was removed using a crane and this helped save time, compared to the normal laborious and time-consuming process of workers hammering it to pieces and then removing these.A pipe made of mild steel replaced the damaged one and it was being welded into place around 1.15 p.m. Again, the dry weather helped speed up this process. Though a bit cloudy, there was not even a drizzle in the city or the suburbs till afternoon. Rain would hold up welding and lead to a cascading effect on the rest of the process of restoring water supply, the official explained.
Work would have been even faster, but a lot of silt had entered the adjoining pipes after being sucked in through the breach. A lot de-watering too had to be done, the official said.An official source in the Corporation said that even if the pumping of water began on Friday night, normal supply to the public would resume only on Sunday. The full quantity needed for normal supply in the city would be available in the 30-lakh litre main service reservoir only past afternoon on Saturday. From here, water had to be supplied to 19 overhead tanks in the city, varying from 2.5 lakh litres to 27 lakh litres in capacity.
It would take 10 hours for water to reach the city from Velliyankadu.After the first motor was switched on, it would take two hours for water to reach Kattan Hills. Only then would the second motor be switched on. Later, the other two motors would be activated one after the other. All the four motors would have to run for normal flow of water to the city.Once it reached the city, it would take four hours for the main service reservoir to fill up and another eight hours in the case of the other tanks. Therefore, normal internal distribution in the city would normalise only on Sunday.