Rock collapse floods Tarbela 5th Extension tunnel and powerhouse; all workers safe, work suspended

SWABI: A rock mass collapsed on Monday during excavation work at Tarbela Dam’s 5th Extension Project, sending a surge of water into a connecting tunnel and the under-construction powerhouse. The Water and Power Development Authority (WAPDA) said an emergency was declared, construction was suspended indefinitely and every worker was moved to safety. No one was killed or injured.

WAPDA said the collapse happened during excavation of the second Bench Connecting Tunnel, when a weak rock formation gave way and water from the Intake Pit poured into the tunnel and powerhouse area. The statement said the Intake Pit had been completely drained, no more water was entering the downstream work sites, and dewatering of the powerhouse had begun.

One worker swept away, pulled out alive
District officials said one Pakistani worker was swept into the water as the tunnel flooded but was rescued by emergency teams. Haripur Deputy Commissioner Waseem Ahmed visited the site and confirmed that all Pakistani and foreign workers were safe. WAPDA dismissed reports that the T-5 tunnel itself had collapsed, saying the main tunnel, the under-construction powerhouse, the tailrace culvert and the switchyard were undamaged. An inquiry has been ordered into the cause of the breach.

Indus flows expected to rise
Swabi Deputy Commissioner Nasarullah Khan said additional water had been released from Tarbela Dam for “unavoidable” reasons and was expected to raise the flow and level of the Indus River. He urged people to avoid bathing, swimming and boating in the river, and asked them not to pay heed to rumours and to follow official notices. A senior district administration official said there was no threat of flooding in areas downstream of the dam at present. The Tribune reported that inflows in the Indus were expected to reach 150,000 cusecs over the next 24 hours.

Second major setback, cost now Rs317 billion
It is the second major incident at the T-5 project in a matter of months. In July, a government inquiry held the contractor, the consultant and WAPDA jointly responsible for an earlier cofferdam collapse, citing unauthorised design changes made after the contract was signed. The project’s cost has climbed from Rs82 billion to Rs317 billion — a rise of more than 285 per cent — and its completion date had already been pushed from 2026 to the end of June 2028 before Monday’s incident. The 1,530MW project, with three units of 510MW each, is financed with $390 million from the World Bank and $300 million from the Asian Infrastructure Investment Bank. Once finished, Tarbela’s total installed capacity will rise from 4,888MW to 6,418MW.