The Dam At The Roof Of The World And What It Means For India

On July 19, Chinese Premier Li Qiang attended a groundbreaking ceremony in Tibet to mark the start of what China calls the Yarlung Zangbo Lower Reaches Hydropower Project. When completed, this will be the largest hydroelectric project in the world, with an installed capacity of 60,000 MW. A hydroelectric project to dam the river in Tibet has been rumoured for decades, and caused several cycles of anxiety in India, because the Yarlung Tsangpo (called Zangbo by the Chinese) eventually, after a formative confluence of tributaries in the foothills of Arunachal Pradesh, becomes the Brahmaputra.

Now that it is finally happening, the reaction from India has been relatively muted. Even Himanta Biswa Sarma, the Chief Minister of Assam, the state whose core is the Brahmaputra valley, has been uncharacteristically measured in his response.

There are at least three clearly discernible reasons for this. One is that, in recent years, the Brahmaputra has come to be better understood by officialdom in India. It is therefore understood that most of the water in the river comes from sources on the Indian side of the border.

Two popular misconceptions, however, remain.

Part isn’t whole

The first is that the Yarlung Tsangpo is the Brahmaputra. It is not; the Brahmaputra is the Brahmaputra. The second, specific to this hydroelectric project, is that this will be the biggest dam in the world. That may not be the case.

The first misconception arises from a popular but excessively simplified image of rivers. The imagination of the world’s great rivers, shaped by their representation on maps, is that of natural canals. There is usually a single neat line that is labelled as the river, and this line is then traced as far back as it can be to what is called the source of the river. The whole thing, from its beginning as a few trickles of water, is understood as the river.

This hydrological convention of tracing rivers to their headwaters has its roots in the “Age of Exploration” between the 15th-17th centuries when intrepid colonial explorers were trotting around the globe “discovering” continents such as America.

Exploration was followed by imperialism and colonialism, and it was in the time of colonialism, as companies such as the East India Company poured resources into the mapping of rivers – the primary mode of inland transport in the absence of proper roads – that the current convention that identifies the Tsangpo with the Brahmaputra began to emerge.

The Brahmaputra as Brahmaputra exists only in Assam.

Lohit’s primacy

The earlier convention, still found in Assamese popular culture, for instance in the songs of Bhupen Hazarika, identified another of the Brahmaputra’s main tributaries, the Lohit, with the Brahmaputra. The Brahmaputra itself is referred to as the Burha Luit or Old Lohit in a celebrated song by Hazarika, the “bard of the Brahmaputra”.

The name Brahmaputra is used for the river only after a confluence of its three formative tributaries, the Lohit, the Dibang and the Siang, near the foothills of Arunachal Pradesh bordering Assam.

The Siang, in turn, is the river that can be traced back and identified as the Yarlung Tsangpo – although that too is a reductive simplification as there are numerous tributaries and streams that flow into the Siang after it enters India.

While the Siang is a significant river, it is by no means the Brahmaputra, because the Brahmaputra has not less than 25 major tributaries. The Siang is not the largest of these tributaries. That honour goes to the Subansiri. The Lohit and Dibang come next, although there are wide seasonal variations in flow especially in the case of the Dibang.

Therefore, a hydroelectric project on the Yarlung Tsangpo is not the same as a hydroelectric project on the Brahmaputra.

World’s largest dam?

Nor is the world’s largest hydroelectric project necessarily the one that must have the world’s largest dam.

This is because of the unique geography of the Yarlung Tsangpo at the place where the project is planned, an area known as the “Great Bend”. In this location, the river makes a tight U-turn around a 7,782 m tall mountain peak, the Namcha Barwa. At the start of its U-turn, the elevation is roughly 3,000 m. At the end, it is less than 1,000 m.

This sharp natural drop of 2,000 m is what the Chinese aim to exploit through the Yarlung Tsangpo project. While official details of the design are scant, Chinese sources have reported on some aspects of the plan.

The idea is to use one large dam to divert a part of the main flow of the Tsangpo into an array of massive tunnels that will be bored under the Namcha Barwa mountain. These tunnels will form a “short-cut” that will carry the bulk of the water which now goes around the mountain through the Great Bend. The water will be passed through a cascade of five hydroelectric power stations where turbines turned by the rushing waters will generate electricity. After passing through the power stations, the water will be released back into the river.

The key feature of this plan is the tunnels, not the dam. They would need to be not less than 20 km long and not less than 10 m wide. The biggest tunnels ever built for a hydroelectric project so far, the Jinping II project on the Yalong River in China, are about 16.6 km long and 12-13 m wide. Incidentally, that project is also located in a mountainous area at a place where the river Yalong, a tributary of the Yangtse, makes a U-turn, known as the Jinping Bend.

Several such tunnels in parallel would be required for the Tsangpo project. To blast a path for them would require several hundred thousand tons of explosives.

High risk project

The engineering challenges and risks in a high-risk seismic zone that has a history of powerful earthquakes are immense. There will always be a risk of catastrophe if a very powerful earthquake were to strike. Since this is a mountainous area, there will also be a high risk of landslides. The tunneling will have to be done two kilometres deep into the earth, where temperatures will be high, through complex geological formations.

The effect on the future of the Brahmaputra is going to be harmful. The river, one of the last great free-flowing rivers in the world, will never be the same again.

That is because the Chinese dam has opened the floodgates for dam building on the Indian side of the border as well. The idea of building not less than 140 dams on the Indian side of the Brahmaputra basin has been around for decades, and received the backing of successive governments. They have made halting or no progress because of resolute opposition from villagers in Arunachal Pradesh.

After the announcement of the Chinese dam construction, the Siang Upper Multipurpose Project, which at 11,000 MW will be by far the largest in India, has already started seeing progress.

Dam-building is out of fashion in the West, where hundreds are being decommissioned to allow rivers to flow free. Indian and China are treading a different path.

The relatively muted response to the Chinese dam should be viewed in the context of Indian efforts going back decades to build dams on this side of the border. Those projects are worth billions of dollars. For example, the Siang project alone is worth an estimated Rs 1.13 lakh crore (US $ 13.2 billion). Money will flow like water once these projects take off.

The popularity of dam-building in both China and India cannot be separated from the financial motives.

Finally, there is also the geopolitical context. India finds itself between US President Donald Trump and a hard place. The geographical reality that we inhabit South Asia and have China as our neighbour cannot be wished away. Recent efforts by the Indian government to repair strained ties would have constrained the Indian response.

The bottom line is that the days of free-flowing rivers in the entire Brahmaputra basin are coming to an end.

(Published under Creative Commons from 360info.org)