VIJAYAWADA: As the flood in the Godavari river has been receding, Polavaram project engineers have resumed construction works of the national project. Works pertaining to strengthening the lower side cofferdam will be taken up in the coming days as some of the completed works were affected due to the floods. Works pertaining to Guide Bund on the left side of the spillway have commenced.
Speaking to TNIE, Polavaram Project senior officials said a guide bund of 500 metres in length and a top level of +52 metres is expected to be completed by September. “Guide Bund is for preventing cross flow and it acts as a protection to the spillway,” the senior engineer explained.
Once the water level decreases to 18 metres from present 20 metres, the inspections and tests to find out the ways and means to address the scour (erosion of soil formed by flood) at the lower cofferdam will be taken. Floods in 2020-21 had created a scour near the lower cofferdam, which was at such a depth that even a 10-storeyed building could be kept inside.
Project officials said that no one expected the “once-in-a-century floods” in July. Normally the flood season commences in August. Therefore, the work schedule for the downstream cofferdam was made for July. Unfortunately, the flood-hit in the second week of July itself, that too at the level never seen in the recent past.
“In fact, construction of the lower cofferdam at the scour region was at different levels of height and the work was interrupted due to the flood. Now, we are waiting for optimum water levels conducive for resuming works at this spot, while the works in the parts of the downstream cofferdam, which were not affected by the flood, are continuing,” the senior official explained.
A downstream cofferdam is designed to be 1,613 metres in length and 30.5 metres in height and the upstream cofferdam is designed to be 2,450 metres in length and 42.5 metres in height. When it seemed that the inflows will cross 30 lakh cusecs during the recent floods, the State government consulted the Central Water Commission (CWC) and with its permission increased the upstream cofferdam height by 1.5 metres, that is up to 44 metres.
“With its previous height, the cofferdam could only stop the flow at 28.5 lakh cusecs, but with the forecast that inflows may cross 30 lakh cusecs, measures were initiated to face such a flow, so as to protect the main dam area,” the senior official explained.
CWC TEAM HAILS DECISION TO RISE COFFERDAM HEIGHT
For the first time after the Godavari flood, a team of experts and officials from the Central Water Commission CWC visited the Polavaram project as part of its routine inspection on Sunday. The team was all praise for the decision to increase the height of the upper cofferdam by 1.5 metres to project the main dam site. It also expressed its satisfaction with the function of the hydraulic gates of the spillway.