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NHPC to take up survey on Polavaram’s diaphragm wall in November

VIJAYAWADA: As Godavari river witnesses frequent floods, the National Hydroelectric Power Corporation will take up a survey on the status of the nearly 900 metres-stretch of the Polavaram project’s diaphragm wall in the first week of November.

This will be done after the flood water recedes to one lakh cusecs at Polavaram in Eluru district.

The 1,400 metres-length diaphragm wall built across Godavari river at a depth of 10 to 90 metres on the riverbed and about 500 metres stretch in two portions suffered damage when the river was flooded earlier. The state government, the Polavaram Project Authority and the Central Water Commission are now trying to find out the present status of the 900-metres D-wall.

The 1,400m diaphragm wall had been built at a cost of Rs 400 crore.

As the AP government along with the central agencies has decided to reconstruct nearly 500 metres stretch of D-wall in two portions, the issue is how to go about with the 900m wall.

The NHPC study would check whether the 900 metres D-wall has any crack on it or damage caused to it by the earlier run of floodwaters. This wall supports the earth-cum-rock-fill dam of the Polavaram project.

In case of any major damage, the authorities have no option other than constructing a parallel diaphragm wall five metres away from the existing wall to its full length. This is estimated to cost Rs 700 crore to Rs 800 crore.

The authorities would face questions when it asks the Centre to fund such a huge amount again for the D-wall as Rs 400 crore was already spent on this. Audit objections may be raised on the wasting of government funds as the D-wall was already constructed and the proposal now is to reconstruct it again if need be.

Polavaram project chief engineer Sudhakar Babu said, “We are waiting for the NHPC survey on the 900m diaphragm wall to find out its status once the floods in Godavari recedes by November. It would take two months to complete the survey.

Based on the survey report, a decision will be taken on having a parallel D-wall or a repair of the damaged portions as the wall serves as the foundation for the construction of the Polavaram dam, he said.

Meanwhile, a joint survey by AP with Chhattisgarh has been completed on submergence of agency areas at 45.72m contour level while the Odisha government is learnt to be not agreeing to a proposal from AP for a similar joint survey in that state.

The Telangana government has asked AP to strengthen the floodbanks at the temple town Bhadrachalam as the recent floods to Godavari have affected several parts of the town.

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