A major construction accident occurred at the Tarbela 5th Extension Project on 09 November, prompting suspension of construction work indefinitely. According to the Water and Power Development Authority (WAPDA), during tunnel excavation of the 2nd Bench Connecting Tunnel, a weak rock mass collapsed, causing water from the Intake Pit to enter the Tunnel and the powerhouse area. WAPDA statement claimed that the main T-5 tunnel, under-construction powerhouse structure, tailrace culvert and switchyard remain structurally undamaged. An investigation has been launched to determine the cause of the breach and senior officers, engineers and the contractor were assessing the situation to address any challenges to Project T-5.
The inquiry might identify vulnerabilities that led to a serious incident and determine responsibility but the tragedy highlights flaws in designs of water projects and their poor execution in recent years. The repeated incidents expose an extremely deficient planning process and lack of oversight and professional capabilities of the engineers of the sponsoring agency as well as those of contractors. This is intriguing as Pakistan has a track record of successfully constructing water reservoirs including large ones and running both irrigation and electricity generation components efficiently. Construction of Warsak dam began way back in 1949 and completed in 1960 with the help of Canadian engineers. A consortium of eight American construction firms started construction of Mangla dam in 1961 and completed the task in 1967. A consortium of Italian and French civil engineering contractors started building Tarbela dam in 1968 and the project became operational in 1977. However, the latest projects are facing technical failures, raising their cost and delaying their completion. The T-5 incident marks the second major structural failure at the site, following a previous cofferdam collapse that an inquiry committee blamed on unauthorized post-contract design changes. These combined failures have escalated project costs by over 285% (rising from Rs 82 billion to Rs 317 billion) and will push the completion timeline far past its original targets. This monumental hike in the cost is over and above the losses that will accrue to the national economy due to late execution of the project. It may also be pointed out that 969 MW Neelum-Jhelum Hydropower Project (NJHP) is currently non-functional due to severe structural failures in its underground tunnel system. On 2 April 2024, a major rock burst and subsequent geological pressure caused a tunnel collapse and blockage roughly 9.8 km from the dam site. This completely cut off the water flow required to spin the turbines, forcing a full shutdown by May 2024. The project has been plagued by design vulnerabilities. It previously suffered a major tailrace tunnel collapse in July 2022, which kept the plant offline for over a year. Shortly after those expensive repairs were completed, the current headrace tunnel failure struck. The tunnels were constructed in highly volatile Himalayan terrain, yet critics and auditors noted that preemptive technical warnings and risk-mitigation measures were repeatedly ignored during planning and construction. As per WAPDA and the Central Power Purchasing Agency (CPPA) the restoration and concrete-lining of the damaged tunnel sections will take until March 2028. This timeline means the plant will face a prolonged four-year closure from its initial 2024 failure. The extended closure has placed an enormous financial strain on Pakistan’s energy sector, causing roughly Rs 42 billion in annual losses and forcing the country to rely on more expensive thermal power. There were also Shadi Kor Dam collapse in Balochistan in 2005 and cofferdam failure at Mohmand dam site. The latest incident at Tarbela shows no lessons have been learnt due to lack of accountability. Departmental inquiries and investigations are not enough as these often lead to camouflaging and passing the buck. An impartial inquiry by reputed engineers should be carried out and proper action should be initiated against those responsible for inflicting huge losses on the national exchequer.
