After a tough, 40-hour-long fight with the obstinate breaches in the five-ft-diameter water mains at Beckbagan, civic engineers restored water supply to south Calcutta early on Tuesday. But the traffic remained chaotic till the evening.
Mayor Subrata Mukherjee announced a reward for the four engineers, Subrata Mondol, Ujjal Sarkar, Hariprosad Roy and Probalpratim Das, and Rs 500 for each of the labourers who undertook the repairs by descending into the trench at Monday midnight.
After all efforts from Sunday morning to mend the ruptures in the water mains, lying hidden under an 11-ft trench full of water, proved futile, the four sub-assistant engineers of the water supply department decided on Monday night to take the plunge. At about 11.45 pm, they descended into the trench, to feel the holes and dents on the upper surface of the huge water mains. They identified about a dozen holes of varying sizes, between 12 inch and two inch in diameter.
This was the first time that the civic water supply department realised what exactly had happened and the extent of damage caused by Larsen & Toubro to the water mains during piling work for the upcoming flyover.
“We had not envisaged dents on the upper surface of the mains. So, all efforts to stop water gushing out of the breach by placing a curved steel plate under pressure on the mains proved futile. The flow of water at high pressure (1 kg per sq cm) swept away the steel plates,” said chief engineer (water supply) Dibyendu Roychaudhury.
The leaks needed to be plugged temporarily to carry out repairs. Following indigenous methods, sal poles were hammered into the holes to plug them. Later, the high-powered Blo-vac machine was operated to suck up the accumulated water.