With just 10 days left for the deadline, the designs of the Polavaram Project cofferdam, which is crucial for releasing water into the canals through gravity, have not yet been finalised.
The State government has announced that it would release water into the Polavaram Right and Left Main Canals by gravity by July 1, 2018 though the project would be completed only by May 2019. It wants to do this by impounding water with the help of a cofferdam (a temporary bund) needed for the construction of an Earth-cum-Rock Filled (ECRF) dam across the main course of the Godavari river. The construction of the upstream cofferdam should begin on October 1 if it has to be completed as planned on June 30, 2018. Once the design is finalised, there are more than one agency that has to approve it. Delay in the conduct of the Electric Cone Penetration Tests (ECPTs) and provision of other data sought by IIT faculty members helping with the design of the cofferdams (upstream and downstream) have had a cascading effect, according to sources.
While the ECPTs advised by Professor Ramana of Delhi IIT and Professor Raju of Chennai IIT have been completed, information on the location of Clay Core and Blanket needed for finalising the design of the cofferdams has still to be provided to them by the contractors who have prepared the draft designs.
“The mere finalisation of designs by the IIT professors may not take much time, but the clearance of the designs by the Central Water Commission (CWC) and Polavaram Project Authority (PPA) is likely to be delayed,” say sources from the State Water Resources Department.
This apart, a cofferdam is also needed downstream the ECRF dam to protect it from water flowing back to the structure during floods. The downstream cofferdam is not that crucial as the force of water on it would be less and it is not necessary for the release of water into the canals. The two cofferdams (upstream and downstream) would ultimately become part of the ECRF Dam.
Releasing water by gravity into the Right and Left Canals by June 2018 is being seen as a tall order because it involves the building up of the spillway, coming up across the diversion in the Godavari, simultaneously with the cofferdam across the main course of the river. The fabrication of the radial gates for the spillway is going on as per schedule and would be completed, project sources said. The spillway is scheduled for completion by July 2018 along with the upstream cofferdam. While there is time till June 2018 for beginning the work on the Earth-cum-Rock Filled Dam, it is the cofferdam that is a cause of concern for the State government.
