Unprecedented flood water in the Swat River has breached the tunnel's protective dyke of under-construction Mohmand Dam, reported 24 News HD TV Channel on Monday.
A report prepared by the Wapda experts said the flood water entered the diversion tunnels from the opposite direction breaching and overtopping the protection dyke, which adversely affected the construction activities at the project.
The report said that concreting of the diversion tunnel was in progress when the water entered and the actual damage would be estimated after the water recedes.
The sources said that a committee will be formed to estimate the loss and reasons behind the damage. WAPDA will send the summary of the investigation team to the Prime Minister for approval.
The sources said that there was no huge damage to the Mohmand Dam structure and construction activities would be resumed immediately after the flood situation was over.