All workers were safely evacuated after a rock collapse allowed water to enter a tunnel and the under-construction powerhouse at Pakistan’s Tarbela 5th Extension Hydropower Project on 9 November, according to the Water and Power Development Authority (WAPDA).
The authority said a weak rock mass collapsed during excavation of the second bench of the connecting tunnel, allowing water from the intake pit to flow into the tunnel and powerhouse area. No injuries or fatalities were reported.
WAPDA said the intake pit had been completely drained and no further water was entering downstream work sites. Dewatering of the under-construction powerhouse had also begun. The authority rejected reports that the Tarbela 5th project’s main tunnel had collapsed, stating that the main tunnel, under-construction powerhouse, tailrace culvert and switchyard had sustained no damage.
Senior WAPDA officials, the project engineer and the contractor were assessing the situation to address any challenges to the project. WAPDA shared a video of the current state of the tunnel on its X account.
