The diaphragm wall of the Polavaram project is under a sheet of floodwater by Friday as a result of the flash flood in the Godavari river.
Excluding the spillway that was designed to withstand up to 50 lakh cusecs of inflow, there is an uncertainty on the structural stability of the other facilities of the irrigation project due to incomplete construction of the main dam, as it is receiving an unprecedented inflow.
The inflow of 19.30 lakh cusecs at the Polavaram project on Friday evening, was beyond the expectations. The outflow is 10.30 lakh cusecs. At the upstream spillway, the water level was +35 metres, and in the downstream of the spillway at +27 metres on Friday evening.
Since 1920s, the river has never witnessed such an inflow at the project in July.
Water Resources Minister Ambati Rambabu, who rushed to the project site, told the media, “The present flood level is scary. We are sure that the spillway can withstand up to 50 lakh cusecs of floodwater discharge. However, the diaphragm wall has been submerged.”
“The construction of the lower cofferdam is incomplete. The floodwater is now entering the diaphragm wall areas from the lower cofferdam. As a result, the entire facility of diaphragm wall has been submerged,” said Mr. Rambabu following a field inspection.
In the earlier flood, the diaphragm wall was partially damaged, leading to an additional project cost of ₹600 crore, he said. Subsequently, several groups of experts had been roped in by the Ministry of Jal Shakti to find a scientific solution for the damage.
“There is no place and scope to proceed with the ongoing works at the site owing to the submergence of the diaphragm wall area,” he added.
“The upper cofferdam, whose construction was completed, will withstand an inflow of 28 lakh cusecs. We fear the consequences of the inflow touching 30 lakh cusecs,” he said.
Accompanied by irrigation engineers, Mr. Rambabu observed that the floodwater was being received at the Polavaram project due to heavy rain in Maharashtra and Telangana.
The impact of the flash flood on the project will be assessed once the flood level recedes.
