Stakeholders blamed for Tarbela-5 cofferdam collapse

ISLAMABAD: A government-constituted inquiry committee has held all three key stakeholders — the contractor, consultant and employer (Wapda) — responsible for the cofferdam collapse at the 1,530MW Tarbela-5 Extension Hydropower Project, citing post-contract unauthorised design changes as one of the main reasons for the incident.

The collapse has contributed to at least a two-year delay and more than 285 per cent cost escalation in the project, whose cost has risen from Rs82 billion to Rs317bn.

As a result, the project’s levelised generation cost over 30 years may rise to around Rs27-28 per unit — the country’s highest so far for renewable energy — making it economically unviable and unsustainable, according to the Planning Commission.

The project, which involves $700m in loans from the World Bank and the Asian Infrastructure Investment Bank, is now targeted for completion by end-June 2028 instead of 2026.

Inquiry body holds Wapda, contractor, consultant responsible as project cost rises from Rs82bn to Rs317bn

“The cofferdam collapse incident resulted from a series of extra-contractual steps and contractual violations at all three levels. The contractor submitted a proposal to change the design of the cofferdam, which was contractually not allowed; the engineer accepted the design deficiency conditionally without ensuring technical compliance; and the employer approved it when construction was about to finish, without questioning the contractual validity of the design change and the technical deficiency,” said a three-member independent inquiry committee.

The committee was led by Federal Flood Commission chairman and the government’s chief engineering adviser Ather Hameed. Its members included the director monitoring and a contract management specialist of the Ministry of Water Resources, who were assigned to investigate the August 2025 collapse.

The 15-page inquiry report seen by Dawn said, “The provisions stating rights and obligations of all parties provided in the contracts (civil works and consultancy services) were overlooked and ignored respectively, leading to construction of a vulnerable cofferdam resulting in structural failure caused flooding, delays and financial loss to the T5 Project”.

It said the parties attempted to attribute the collapse to flooding, but noted that the flows were within annual levels, were not extraordinary and should have been catered for in the original design.

The contractors included Power Construction Corporation of China Ltd, HEI and HEM, while the consultant was the UK’s MM Pakistan-BIDR China. The employer is Water and Power Development Authority (Wapda).

The inquiry report makes startling revelations about how multibillion-rupee infrastructure projects of national importance, involving foreign loans worth billions of dollars, are prepared, contracted, executed and monitored.

With respect to the potential impact of flood-related damage on the overall project, the probe committee, which interviewed all stakeholders in detail before and after site inspection and examined relevant records, noted that “the collapse not only caused immediate suspension of works but also triggered cascading cost vulnerabilities under multiple contractual, as well as financial heads”.

The report said the cofferdam design was changed on the proposal of the contractor, PCCCL, to a rock-filled structure — a weaker option — across the entire project, including the channel, which later led to the collapse.

Wapda approved the design change “without questioning its contractual validity”.

Wapda attributed the collapse to flooding, but the probe committee found that the flows were within Tarbela’s historic record and significantly lower than the cofferdam’s design capacity. It blamed inadequate protection layers and filter arrangements.

The report said Wapda sought a cofferdam performance report in July 2023 from the consultant. “Instead of conducting its own independent review, the consultant forwarded the request to the contractor, who, after a delay of more than one year, submitted a monitoring report in October 2024.”

The report also found that irregular payments were made for temporary work instead of permanent works, compromising the government’s compensation rights against the contractor for the major collapse.

As a result, the project cost increased from Rs82.36bn, approved in 2017, to Rs317bn last month and is still rising.

Wapda terminated the consultancy contract of MML-UK, saying the firm had failed to provide a suitable and adequately qualified project manager and that staffing issues persisted throughout its tenure.

Moreover, MML issued a notice of termination in May 2025 and unilaterally withdrew its staff from the site, contrary to the required 30-day notice period in the contract.

Published in Dawn, July 13th, 2026 ...