Vijayawada: The National Hydroelectric Power Corporation (NHPC) would take up a study on the Polavaram irrigation project’s diaphragm wall across River Godavari at Polavaram in Eluru district to ascertain its present status.
With all major components of the project nearing completion, the state government intends to complete the dam construction without further delay so as to supply water for drinking, irrigation and industrial needs in parts of AP.
As the state experienced a long spell of rainfall under the influence of the southwest monsoon, resulting in heavy floods in Godavari, the planned study was delayed. The plan was to take up the assessment from December 15.
The Polavaram Project Authority and the department of water resources have asked the NHPC to take up the study while the water in the river is at normal level. They have promised to pay the amount once the study starts.
The NHPC would pay nearly Rs 80 lakh in advance for the study by mobilising equipment and experts.
The diaphragm wall measures a 1.5 metre thickness with a 40-80 metre depth and stretches to a length of 1,400 metres. Nearly a 600-metre stretch of the wall suffered damage in two segments when the river was flooded some time ago.
The state water resources department completed the preparatory works on the diaphragm wall to enable the NHPC start the study. The NHPC team of experts would pass electric waves through the wall to gauge the fitness of the structure.
If there’s any damage or if the wall was filled up with material like sand instead of concrete, the tests would take note.
If so, water resources authorities feel the way forward is to reconstruct the damaged portions of the diaphragm wall and connect these to the undamaged portion.
They are also having an option of taking up construction of the new diaphragm wall for the entire stretch, parallel to the existing one. A decision could be taken based on the study results.
The experts are expected to also take up technical studies like seismic tomography to ascertain the ability of the structure to withstand high pressure from the water stored for distribution via pipes or canals for various requirements.
The NHPC study would take a month’s time, followed by another 45 days for preparation of the report.
Polavaram project superintendent engineer Narasimha Murthy said, “We are expecting that the NHPC would start the study soon.”
