VIJAYAWADA: The Water Resources department is preparing to launch major works related to upstream and downstream cofferdams of Polavaram project by early December. While the preliminary works have already begun, officials said, the cofferdams are likely to be ready in six months time. The State government has promised to release water from the project, through gravity, by mid-2019.
While the foundation for the cofferdams — jet grouting — has been completed, the officials are now in the process of mobilising necessary men and machinery for launching the major works. “The preliminary works are already underway, but we expect to launch the major works by December 15,” Polavaram project Chief Engineer (CE) V Sridhar told TNIE. According to the officials, while 58 lakh quantities (units) of material works have to be done for the upstream cofferdam, the lower cofferdam has 25 lakh quantities of rock, soil, fine and coarse material works.
The CE said the uneven surface on the surface of the jet grout columns, which the project detractors alleged were due to poor quality of construction, was the residue. “The actual jet grout columns are below the surface. The uneven part is called residue, which is the excess part formed, while bringing the jet grouting machine to a halt. Since the machine, which runs at a pressure of 400 to 500 bar, can’t be brought to a halt immediately; the pressure is tapered down slowly, which results in the residue,” Sridhar said.
The representatives of Keller India, which has done jet grouting, explained that a daily quality audit was a part of their functioning. “The machines we used have Data Acquisition (DAQ) software and we transfer it to our teams in Australia and the US, which examine the parameters thoroughly,” one of the representatives said.
The CE added, the government conducts periodical quality checks. “There is a Quality Control wing in our department, then there is Water and Power Consultancy Services Ltd, the project consultant appointed by the Centre, and there are Polavaram Project Authority and Central Soil and Material Research Station. We also have experts from IIT, Madras, for quality inspections. So, there is no scope for lapses in quality of the execution,” he said.