Three representatives of L&T, which built the Medigadda Barrage, made it clear before Justice PC Ghosh Kaleshwaram Commission on Friday that the Medigadda Barrage collapsed due to design flaws.
The CDO department had prepared the designs with the expectation that the flood would jump out of the barrage gates at a speed of 6 meters per second (shooting velocity) and hit the ground below, but a study conducted by IIT Roorkee showed that the actual speed was 16 meters per second, L&T Hydel Project Department Vice President S. Suresh Kumar told the Kaleshwaram Commission.
He said that IIT Roorkee had conducted a review of the barrage designs and concluded that there were flaws. L&T Project Director MV Ramakrishna Raju revealed that the barrage suffered major damage when the Medigadda Barrage was first filled with water in 2019.
After the floods subsided, when the gates were lowered and inspected, it was found that the CC blocks below the barrage had been washed away and the apron had been completely destroyed, and they reported this to the Irrigation Department.
They revealed that the Irrigation Department had failed to provide them with revised designs and drawings to correct the defects in the barrage. As a result, the problem escalated and the 7th barrage collapsed on October 21, 2023, he said.
He explained that after the construction was completed, the barrage was kept completely filled with water for five consecutive years, which made it impossible to conduct inspections before and after the monsoon season as per the rules.
When similar problems arose in 2019 at Medigadda and other barrages, the executive engineer at the field level wrote a letter to the authorities requesting them to conduct model studies again with the Telangana State Engineering Research Laboratories (TSERL) under the auspices of the Central Designs Organization (CDO) design engineers of the Irrigation Department.
In June 2020, to assess the damage to Medigadda and other barrages, experts from the Central Water Power Research Station (CWPRS) and CDO engineers visited the field and tested them. The CDO team conducted model studies with TSERL on different alternatives to reduce the shooting velocity of the flood flow released from the barrage.
L&T Project Manager Ramakrishna Raju disclosed in detail that an expert committee comprising retired ENCs had visited Medigadda and other barrages in March 2022 and said that the shooting velocity needed to be reduced, but the barrage sagged due to the lack of revised designs.
When the commission asked him, “Are you not responsible for examining the designs and drawings given by the Irrigation Department to see if they are correct?”, he clarified that they, who had secured the work under the piece rate contract system, had no involvement in the preparation of the designs.