Key takeaways: Water flooded Tunnel Five at Tarbela’s T-5 hydropower project on Monday after a rock collapse breached a protective bund. Work is suspended indefinitely and an inquiry is under way. No one was killed; one worker swept away was rescued.
Construction on the Tarbela Dam’s 1,530-megawatt fifth extension has been suspended indefinitely after water flooded Tunnel Five and the under-construction powerhouse on Monday. A weak rock mass collapsed during excavation work, allowing water from the intake pit to surge into the site, the Water and Power Development Authority (WAPDA) said. All workers were evacuated safely and no one was killed.
The breach happened during excavation of the Second Bench Connecting Tunnel, when the collapsed rock opened a path for water from the intake pit into the tunnel and powerhouse area. Haripur Deputy Commissioner Waseem Ahmed, who visited the site, said one Pakistani worker was swept into the water but was rescued by emergency teams. Construction work has been suspended indefinitely and an investigation launched.
WAPDA said the water in the intake pit has been completely drained and no further water is entering the downstream work sites, while dewatering of the powerhouse has begun. The authority rejected social media reports that the main tunnel had collapsed, saying the main tunnel, the under-construction powerhouse, the tailrace culvert and the switchyard were undamaged. WAPDA officers, the project engineer and the contractor are assessing the situation.
The district administration has ordered a high-level inquiry to establish whether a structural weakness or a technical fault caused the protective bund to fail, Ahmed said. The next course of action will be decided once the inquiry report is received. Meanwhile, Swabi Deputy Commissioner Nasarullah Khan said additional water had been released from the dam for unavoidable reasons, raising the flow and level of the Indus River, and urged people to avoid bathing, swimming and boating in the river. Officials said there was no threat of flooding in areas downstream of Tarbela at present.
A project already years late
Monday’s incident is the second major failure at T-5 in a matter of months. In July, a government inquiry committee held all three key parties, the contractor, the consultant and WAPDA itself, responsible for an earlier cofferdam collapse, citing unauthorised design changes made after the contract was signed. That failure added at least two years to the schedule and pushed the cost up by more than 285 percent, from Rs82 billion to Rs317 billion. The project had been due for completion by the end of June 2028, instead of 2026, before Monday’s incident.
T-5 converts Tunnel Five of Tarbela Dam into a power tunnel with three generating units of 510 megawatts each, adding 1,530 megawatts to the dam’s capacity. Once finished, it would raise Tarbela’s total installed capacity from 4,888MW to 6,418MW. The World Bank is providing $390 million and the Asian Infrastructure Investment Bank $300 million, while China’s Power Construction Corporation holds the $354.6 million civil works contract awarded in May 2021.
Why it matters
T-5 is one of Pakistan’s largest hydropower additions, and every delay pushes back the cheap electricity it was meant to supply as the country manages a winter gas crunch. The pattern is the deeper concern: two failures in four months on a project already years late and hundreds of billions of rupees over budget, with a July inquiry blaming all three parties involved. Monday’s inquiry will need to show whether the latest failure was bad geology or a repeat of the oversight problems found in July.
What happens next
The high-level inquiry will determine the cause of the breach and the next steps. Dewatering is under way while WAPDA assesses the damage. No restart date has been given, and the completion date of June 2028 is now likely to slip further.
Frequently asked questions
What happened at Tarbela Dam on Monday?
A weak rock mass collapsed during excavation of the Second Bench Connecting Tunnel at the T-5 hydropower project, letting water from the intake pit flood Tunnel Five and the under-construction powerhouse. An emergency was declared, workers were evacuated and construction was suspended indefinitely.
Was anyone hurt?
No. All workers were evacuated safely and no casualties were reported. One Pakistani worker who was swept into the water was rescued by emergency teams.
What is the T-5 project?
The Tarbela 5th Extension converts Tunnel Five of Tarbela Dam into a power tunnel with three 510-megawatt units, adding 1,530 megawatts and raising the dam’s total installed capacity from 4,888MW to 6,418MW.
Sources
- Dawn, “Water surges into Tarbela project site after rock collapse,” November 10, 2026
- The Express Tribune, “Tarbela T-5 project work suspended indefinitely after protective bund breach,” November 9, 2026
- Republic World, “Worker Swept Away, Tunnel Flooded: Inside The Tarbela-5 Bund Collapse,” November 10, 2026
