Islamabad: A serious accident has occurred in the fifth expansion project of the Tarbela Dam, one of Pakistan’s most significant hydroelectric projects. During construction activities at the Tarbela Dam, located on the Indus River in Khyber Pakhtunkhwa Province, a rock collapse led to water flooding into the tunnel and powerhouse areas. Consequently, all construction work has been completely stopped.
The Pakistan Water and Power Development Authority (WAPDA) confirmed that the accident took place today (November 9). While mining operations related to the tunnel excavation were ongoing as part of the Tarbela fifth expansion project, a large unstable rock mass suddenly collapsed. This disruption obstructed the water flow control section, causing water from the dam to rapidly surge through the intake pit into Tunnel Number Five and the powerhouse area.
At the time, numerous Pakistani workers, foreign engineers, and technical experts were present at the construction site. The unexpected flooding created significant confusion among the workers, who quickly attempted to move to safe locations. Rapidly rising water inside the tunnel complicated rescue efforts; however, authorities successfully evacuated all personnel safely. WAPDA reported that rescuers timely saved a Pakistani worker who had been submerged in water. Thankfully, despite the high risk, no fatalities have been reported.
WAPDA officially explained that the flood mainly affected Tunnel Number Five, the intake pit, and the powerhouse construction zone. Water entered these areas mixed with silt, rock fragments, and other debris, making it impossible to continue construction. Following the accident, investigations into the safety of various machinery and construction equipment across project sites have begun. Work can only resume once the water inside the tunnel is fully removed and the construction area is certified safe.
Meanwhile, WAPDA clarified that the main dam structure and existing powerhouse remain unaffected by the incident, and there is no reason for concern about the dam’s overall safety.
The Tarbela Dam, located along the Indus River in Khyber Pakhtunkhwa, is one of the largest earth and rockfill dams worldwide. Construction began in 1968 near the capital Islamabad and major operations were completed by 1976. The project aims to provide irrigation facilities for Pakistan’s agricultural sectors, regulate the Indus River flow, reduce flood risks, and generate substantial hydroelectric power. The installed capacity of Tarbela Hydroelectric Power Station is approximately 4,888 megawatts.
The fifth expansion project aims to increase Tarbela’s generating capacity in response to Pakistan's growing electricity demand by installing new generation units and expanding related infrastructure to better utilize existing water resources.
The flooding incident has dealt a setback to the project's progress. Authorities are assessing the impact and estimating the time needed for necessary repairs before clarifying the project’s next steps. Following the accident, WAPDA launched emergency operations to drain water from the intake pit, which has now been discharged. Removal of water, silt, and rock debris from the powerhouse and tunnel areas is ongoing.
Additionally, inspections are underway to determine if the flood damaged the tunnel interior or construction equipment. After full drainage, technical experts are expected to conduct comprehensive safety evaluations.
WAPDA emphasized that there is no damage to the primary dam or existing power generation systems and that construction activities will not resume until the site is declared safe.
A detailed investigation has been initiated under the leadership of the Haripur Deputy Commissioner to ascertain the true cause of the accident. The probe will examine if sufficient safety precautions were observed during mining, if the risk of rock collapse could have been anticipated, and whether there were any failures in the water flow control mechanisms for the tunnel.
Construction of the Tarbela fifth expansion project will remain suspended until the investigation concludes. This pause has raised concerns over potential delays to the project’s scheduled completion, which could lead to increased financial costs and technical challenges.
Given Pakistan’s urgent need to meet rising electricity demand and reduce dependency on imported fuels, timely completion of major hydropower projects like Tarbela is critical. Hydropower helps supply electricity at relatively low cost and is vital for the country’s energy security.
Currently, the primary focus of authorities is to clear water and debris from the tunnel, determine the accident’s cause, and complete thorough safety inspections.
Although a major disaster was averted by successfully evacuating all workers, the suspension of the Tarbela fifth expansion—a key component of Pakistan’s future power generation capacity—presents a new challenge for the authorities.
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Original Malayalam report: Malayalam Daily News
