NDSA submits first report recommending interim measures for Medigadda

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Quoting reports received from the Irrigation Department, the Committee said 77 out of 85 radial gates in Medigadda Barrage have been successfully lifted.

Hyderabad: The National Dam Safety Authority (NDSA) committee investigating the safety and structural issues of the Medigadda, Annaram and Sundilla barrages, key components of the Kaleshwaram Lift Irrigation Project, has submitted a report recommending interim measures to be taken up before the onset of monsoon to prevent further damage to the project.

The committee made the recommendations based on physical inspection of the barrages, interaction with officials of the Department of Irrigation and Command Area Development (CAD) and other stakeholders, and after initial round of examination of documents submitted by the departments involved in implementation of the project.

Quoting reports received from the Irrigation Department, the Committee said 77 out of 85 radial gates in Medigadda Barrage have been successfully lifted.

However, problems were encountered while lifting the remaining radial gates No.15 to 22 in the distressed block No-7. The Committee has been requested to suggest the way forward on the lifting of the remaining eight radial gates for carrying out the works before the onset of the coming monsoon. Block No-7 on which the remaining eight radial gates are resting, is in a ‘highly distressed state’.

The piers along with the raft in Block No-7 have sunk to varying depths and piers tilted to varying degrees. The worst affected Pier No 20, which has sunk by over 1.2 m is precariously standing, with the reinforcement completely sheared off along the wide-crack.

The crack is running along the full height of the pier, just upstream of the radial gate wall plate of Pier No. 20, it said. Interim recommendations The committee suggested that crack monitoring at appropriate locations should be carried out.

As for Piers no.16 to 22, they are have either tilted or have developed cracks to varying magnitude, and should be adequately addressed at appropriate locations with suitable bracing systems. Defective or damaged pressure release valves in the raft should be rectified or replaced.

The optical targets shall be installed on top level of all piers of Block No-7, one each at the upstream end, at the downstream end and at the middle.

They should be continuously monitored and a record maintained. Among other recommendations, the report also said the radial gates adjacent to pier no 20 ( Gate No 20 and 21), which suffered maximum damage, should be removed completely by dismantling and cutting the gate from the assembly, and be taken away.

The remaining six gates should be lifted and kept in fully open position and shall be latched firmly. In case of any difficulty in lifting any of these gates to fully open position, the gate shall be removed completely.

The committee also recommended that the damaged cement concrete blocks be replaced and the dislodged apron along with toe wall be restored back to its original approved drawings.

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