China's new dam project is going to be a massive engineering marvel over a politically important river, writes . 

Plans for a series of huge dams on the Yarlung Tsangpo River (the upper part of the river which becomes the Brahmaputra in India) have recently been announced by China. Built as part of the country's hopes to reduce its dependence on fossil fuels, the dams could potentially dwarf the huge Three-Gorges Dam. 

However, the river in question is important for several countries along its course and supports some of the most important ecosystems in Asia. Realising this ambitious, and some might say controversial, project is going to require some very savvy diplomacy, and careful planning indeed. 

What is the Yarlung Tsangpo Dam project?

In November of 2020, the Chinese state-owned media announced plans for the construction of a series of new hydro electrical power plants in the foothills of the Himalayas. Billed as potentially the world's biggest (once complete), the dam is set to be a massive engineering undertaking and a very controversial one too. 

The Yarlung Tsangpo Dam project will be, it is been announced, a 60-gigawatt mega-dam that may, so it is claimed, bigger than the mighty Three-Gorges Dam. The selected site is on the Yarlung Tsangpo river (known as the Brahmaputra in India), which is one of the world's highest major rivers. 

The town of Ngawa on the Tibetan Plateau. Source: Jailiang Gao/Wikimedia Commons

From its source in the glaciers of the Manasarovar Lake region of the Tibetan Plateau, the river begins at heights of over 16,404 feet (5km) and snakes its way from west to east through the Himalayan mountain range.

The river runs along, roughly speaking, a huge geological rift created by the impact of the Eurasian plate, and cuts through the Tibetan Plateau until it meets the point where the Himalayas, the Nyenchen Tanglha, and Hengduan mountains meet.

From here, it pushes its way between the Gyala Peri and Namcha Barwa peaks to form the world’s deepest gorge, then makes its way through Arunchal Pradesh (India) and flows southwest through the Assam Valley in the south through Bangladesh (where it is called the Jamuna) and to the vast Ganges Delta, where it merges with the river Ganges to become the Meghna river, before emptying into the Bay of Bengal.

At one point in the river's course, it plunges 8,858 feet (2,700 metres) through the Yarlung Tsangpo Grand Canyon, forming an enormous gorge more than twice the depth of the Grand Canyon in the United States.

Towards the end of the 1990s, the gorge was recognised as the world’s deepest. In the 400km from the top of the gorge, the river twists around the mountain of Namcha Barwa (known as the Great Bend) and loses more than 6,562 feet (2,000 metres) in altitude, forming several waterfalls and giving up huge energy potential as it goes.

Yarlung Tsangpo River near Namcha Barwa. Source: Jiang Jianhua/Wikimedia Commons

"Hydropower experts say a tunnel that cuts the river’s natural loop could carry 2,000 cubic meters of water a second, with a drop in altitude of 9,186 feet (2,800 metres) – enough to power a 50-gigawatt hydropower station that could provide 300 billion kilowatt-hours of electricity a year. It would be the largest hydropower project in human history – about three times the size of the Three Gorges Dam," sayss China Dialogue.

Today, the plan is to build eleven hydropower stations on the river. Three of these will be along the middle reaches from Sangri to Gyaca, and the other nine in the gorge up to the Great Bend.

In 2010, work started on one of the three planned dams on the Sangri-Gycaca section.

The Tibetan Plateau is a very important source for many of the major rivers in Asia. For this reason, it is one of the most important ecosystems on the planet – not to mention one of huge geopolitical and strategic importance. 

For this reason, this particular part of the river might prove to be a perfect place to plonk a hydroelectric power plant. The site is, roughly 30km from the Indian border. 

The proposed dam(s) is part of China's commitment to becoming carbon neutral by 2060. 

Once built, the new dam(s) could dwarf the Three Gorges Dam. Source: Le Grand Portage- Rehman/ Creative Commons

What's more, it is not only China that is interested in building dams on the river. India has also proposed hydropower plants along the Yarlung Tsangpo and its tributaries on a large scale.

Public and private proposals include up to 160 huge dams along its course, that should be able to harvest about 57 gigawatts of power in the country's northeast. 

Owing to the location, and the project's proposed scale, the Chinese dams could, in theory, produce as much as three times the power of the Three Gorges dam. Proposals for the project date back to the 1990s, when the government conducted a series of hydropower development surveys of the river. 

While the Three Gorges Dam required the relocation of about 1.4 million people, the area around the Yarlung Tsangpo is relatively sparsely populated, so the human cost of the proposed dam should be considerably less. 

It is important to note, however, that the new dam is not the only one on the river. To date, various medium- to small-sized dams are already in place. 

What are the potential costs of the Yarlung Tsangpo Dam project?

Dams are expensive enterprises in and of themselves, but that is not the only cost to their construction. The construction of dams tends to seriously impact local ecosystems and communities too. 

Yarlung Tsangpo River as it courses through Tibet. Source: NASA/Wikimedia Commons

This part of the world, particularly the Yarlung Tsangpo Gorge, is geologically young and is still a very active formation. For this reason, the area is subject to many geological stresses and seismic activity, and landslides are relatively common affairs. 

To this end, the gorge, in and of itself, is still something of a work in progress, with hundreds of active landslips and mudslides that could be worsened by future seismic activity. 

For example, in the 1950s, a magnitude 8.0 earthquake rocked the area, causing many secondary landslides that inundated some parts of the region downstream.

In early 2000, another huge landslide at Yi'ong caused the formation of a four billion cubic metre barrier lake. Two months later, the barrier failed, resulting in floods that affected millions of people. 

From an environmental point of view, this area is also likely to be seriously impacted. For example, the effect of long-term climate change on the Tibetan Plateau is currently still something of an unknown quantity. 

As average temperatures have been on the rise, the glaciers and snowlines of the Himalayas have been retreating at an alarming pace. These glaciers are the primary source of freshwater for the many rivers of the region, including the Yarlung Tsangpo, that use the mountain range as a source. 

Source: Bernard Gagnon/Wikimedia Commons

Should they disappear completely, the watershed of many rivers will be seriously impacted – potentially turning many downstream regions into deserts. 

The ecosystem of the gorge is also potentially in for some trouble if the dams are built. Already embattled, the trees of the primary forest are considered by some to be over-mature and secondary growth is largely mono-cultural, leading to a decline in vitality. 

The local peoples of the gorge, like the Monpa and Luopa, use slash-and-burn methods of farming, destroying large swathes of trees to create farmland and accelerating soil erosion. This also impacts the area's wildlife, much of which is now endangered and facing extinction and the ecosystem of the gorge and surrounding areas have become fragmented.

The added pressure of a series of huge dams will undoubtedly prove too much for some of these fragile ecosystems.

But, the area in question is also of great geopolitical importance too.

The 2.5 million sq km Tibetan Plateau is rich in natural resources and also borders several nations. The watershed of the Himilayas provides drinking water to almost two billion people in countries including India, China, and Bhutan. 

Any perturbation in this supply could have dire consequences for people who rely on this water to survive. 

The river crosses various international boundaries which, should the dams be built, could cause some geopolitical tensions. Source: Wikimedia Commons 

In fact, some have speculated that the Chinese Communist Party (CCP) included the potential control of the water source for a large part of India when it considered the invasion of Tibet almost 70 years ago. 

The Yarlung Tsangpo flows into Bangladesh downstream, too. It is feared that the CCP could attempt to use the construction of the dam, especially so close to the border, for leverage against India and Bangladesh in the future too. 

This, coupled with recent border tensions between India and China, have not gone unnoticed. The US, for example, has been making attempts to broker some form of official resource-sharing policy between the two nations for a few years now. 

Some legislation to help deescalate the situation has been passed, like the Tibet Policy and Support Act. This act outlines a commitment to: “encourage a regional framework on water security… to facilitate cooperative agreements among all riparian nations … on the Tibetan Plateau.”

But there is also legal precedent in international law, like the International Water Courses Convention, which was adopted by the United Nations in 1997. This sets out certain rights and duties in relation to trans-boundary river flows.

But, Bangladesh, India, and China have not yet officially signed up to the convention. China has, however, made some public announcements to allay concerns. 

“China will continue to maintain communication with India and Bangladesh through existing channels. There is no need for the outside world to over-interpret it,"  says Hua Chunying, a spokesperson for the Chinese Foreign Ministry.

(Main image: Yarlung Tsangpo River near a Tibetan village)

This article was written by and first appeared in Interesting Engineering.