Hyderabad: An expert team of the National Hydro Power Corporation (NHPC) that inspected the Polavaram project site recently has favoured the completion of the spillway works before taking up the coffer dam.
The spillway controls the release of water, such as in a river, to a downstream area. A coffer dam provides a dry space under the water line to carry out construction work,
The NHPC panel was appointed by the Union water resources ministry to go into the fresh proposals received from Polavaram Project Authority to take up both spillway and coffer dam work simultaneously.
The report comes ahead of the visit to the project site by Union water resources minister Nitin Gadkari, who has to decide on the state government’s recommendation on change of contractor.
The NHPC report, submitted to the Centre on December 28, said, “The diversion of Godavari river through the spillway and completing the coffer dam up to an elevation of 42.5 metres in the present lean season to facilitate supply of water to irrigation canals appears unlikely to be achieved.”
It said it was prudent that the spillway is completed before the start of the next lean season to divert the river flow.
It said constructing a part of the earth-cum-rock fill (ECRF) dam in a zone of higher river bed level without the upstream coffer dam was prima-facie feasible. This part of ECRF dam will act as a coffer dam in combination with the coffer dam constructed in the balance width of river in same lean season.
It said construction of this part of ECRF including the foundation treatment may be undertaken in the next lean season, after completing the alternative route for river diversion.
