Chinese Study Raises Safety Concerns Over Brahmaputra Mega-Dam on Active Fault Line

A study by Chinese geologists has found that an active fault line beneath the world’s largest hydropower project on the Brahmaputra River in Tibet could affect its structural stability, raising questions about Beijing’s repeated claims that the dam would help prevent disasters in the region.

The project, located close to the Indian border in Arunachal Pradesh, is being built in a massive gorge where the Brahmaputra makes a sharp U-turn before flowing into India and later Bangladesh.

In a paper published last month in the Chinese-language journal Sedimentary Geology and Tethyan Geology, researchers from the state-owned China Geological Survey said the Paizhen Fault, which has been highly active since the Pleistocene epoch, “will have a major impact on the structural stability and construction of nearby structures, including dams, roads, bridges and tunnels, as well as the reservoir area.”

According to the researchers, prolonged fault activity has fractured and weakened the surrounding rock formations, making the foundations and structural stability of nearby engineering projects more vulnerable to damage. “The Paizhen area is located within the reservoir area of the Yarlung Tsangpo downstream hydropower station,” the paper said, referring to the Brahmaputra by its Chinese name.

China formally began construction of the $167.8-billion dam on the Brahmaputra in Tibet last July. Expected to generate more than 300 billion kWh of electricity annually, the dam is projected to meet the annual power needs of more than 300 million people.

The project is being built in a region along a tectonic plate boundary that experiences frequent earthquakes. The Tibetan Plateau, often called the “roof of the world,” is prone to periodic earthquakes because of the movement of tectonic plates beneath it. The researchers cited the magnitude 6.9 earthquake that struck Milin in Tibet in 2017 near the northern end of the fault as evidence that the fault remains seismically active.

“Under regional seismic action, landslides and collapses can easily be induced, threatening the safety of engineering facilities and personnel,” they said.

The recent findings add to concerns over the project’s structural safety, with the researchers urging engineers to reinforce vulnerable slopes and install retaining structures to reduce the risk of landslides and collapses.

However, China has consistently sought to allay concerns. An official statement in December 2024 said the hydropower project was safe and prioritised ecological protection. “Through extensive geological explorations and technical advancements, a solid foundation has been laid for the science-based, secure, and high-quality development of the project,” it said.

In July last year, a Chinese Foreign Ministry spokesperson said China was highly responsible in developing cross-border rivers and had rich experience in building hydropower projects. He said the project strictly followed the highest industry standards and would help prevent disasters along the river without negatively affecting downstream regions.

The Brahmaputra flows across the Tibetan Plateau, carving out the world’s deepest canyon before entering India. The study was supervised by the China Geological Survey.