Haripur: Construction on the Tarbela Dam Fifth Extension Hydropower Project (T 5) has been suspended indefinitely after a protective bund gave way on Monday, allowing water to flood Tunnel Five and forcing workers to evacuate the site.
Haripur Deputy Commissioner Waseem Ahmed confirmed the incident following an inspection of the project area. He said district authorities and rescue teams evacuated all Pakistani and foreign workers to safety.
One Pakistani worker was swept away by the incoming water but was subsequently rescued. No deaths were reported. The district administration has ordered an inquiry to establish whether the bund failed because of structural weaknesses, technical faults or other factors.
Ahmed said further decisions regarding construction would be taken after the investigation report was submitted. Authorities have not announced a date for work to resume.
Project aims to expand electricity generation
The T 5 extension is being developed by the Water and Power Development Authority (WAPDA) to increase electricity production at Tarbela Dam, one of Pakistan's main hydropower facilities. The project involves installing three generating units, each with a capacity of 510 megawatts, adding a total of 1,530MW to the dam's existing generation capacity.
Once operational, the extension is expected to raise Tarbela's installed capacity from 4,888MW to 6,418MW and generate approximately 1.347 billion units of electricity annually. In May 2021, WAPDA awarded a USD 354.6 million civil works contract to China's Power Construction Corporation of China Limited.
The project's approved cost was USD 807 million, with financing arrangements including USD 390 million from the World Bank and USD 300 million from the Asian Infrastructure Investment Bank.
Previous delays raise concerns over completion
The latest suspension adds uncertainty to a project already affected by construction and administrative delays. Originally planned for completion within five years, the extension's deadline was subsequently moved to September 2027.
In September 2024, project officials informed a Senate committee that delays had resulted partly from difficulties in obtaining permission from the Indus River System Authority (IRSA) to close Tunnel Five for construction.
Work was also temporarily suspended in August 2025 after rising reservoir levels and increased water inflows affected the construction site. The recurrence of flooding raises questions about water management and the protection of construction infrastructure during work at the dam.
The latest incident could place further pressure on the revised completion schedule, although officials have not yet assessed its financial or operational consequences.
For Pakistan's electricity sector, the extension represents additional hydropower capacity that could reduce dependence on more expensive generation sources when sufficient water is available.
Any prolonged delay would postpone those anticipated benefits and could require changes to construction schedules and project expenditure. The inquiry's findings will determine the next steps, including any repairs or engineering changes needed before construction can safely resume.
