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How China’s Draconian megadams are causing the slow strangulation of Tibet’s mighty rivers

In April 2019, a colossal new project, Lawa Megadam, was given the green light by Chinese authorities. Located in the upper reaches of the Yangtse River, bordering Tibet, Lawa Megadam is projected to be 239 metres tall from the base up—which is the height of a 70-storey building, and roughly twice the height of the Potala Palace in Lhasa. Upon completion around 2025, the US$4.6-billion Lawa Megadam will generate 2.24 Gigawatts of power.  This will be the largest dam ever built in Tibet. 

 

The site of LAWA megadam, on the Sichuan-Tibet border.

The dam is being built by China Huadian Corporation, which also has a monopoly for all dam construction along the Salween River. Like other State-run dam-builders, Huadian operates in secrecy, rarely revealing its plans, and rushing the construction through before protesters have time to react. Very little, if anything, is done in the way of EIA (Environmental Impact Assessment), and local communities are kept in the dark. Or else they are given vague promises of how this new dam will benefit them—when in fact the dam will likely destroy their livelihoods of fishing and farming. Forced relocation of farmers from fertile lands to poor land is common when flooding a region for a dam reservoir.

This map shows Lawa megadam on the Yangtse, near Batang. This map is older, showing plans for dams on the Drichu (Yangtse), Zachu (Mekong) and Gyalmo Ngulchu (Salween).

 

Why Tibet? Because it has the highest peaks and the deepest gorges on earth—and the fastest-running rivers. As China overcomes the technical challenges of dam construction at altitude, the dams in Tibet are becoming bigger and bigger. The Tibetan plateau is generally defined as anything over 2600 metres in elevation. There are a number of smaller dams in Tibet—and many more on the drawing-board. Zhangmu Dam, located on the mid-reaches of the Yarlung Tsangpo River, is relatively small, at 510MW output, but Chinese engineers are building four more dams in a cascade in this region—which will impact both Bangladesh and India downstream. Zhangmu Dam is not close to any industrial centre, though it is within reach of Chinese mining operations. With the introduction of Ultra-High Voltage lines, it doesn’t matter. These UHV lines can transmit power from megadams in Tibet all the way to coastal China, some 3,000 kilometres away. This technology has proven a game-changer in dam-building strategy, as even a decade ago, the power generated by a megadam was confined to the region of its location.

To put this all in perspective, consider the following engineering feats. In 1935, the largest dam in the world was Hoover Dam on the Colorado River in the US, generating 2 Gigawatts of power output. Today, that dam is dwarfed by the Three Gorges Dam on the mid-section of the Yangtse River. At 22 Gigawatts in power output, the Three Gorges Dam generates ten times the output of Hoover Dam. Three Gorges Dam eclipses all descriptions for Large Dam, Megadam, and even Monster Dam. As the largest dam on the planet, and the largest concrete object on earth, the Three Gorges Dam is in a class of its own—best described as the Mother of All Dams, or the biggest dam in the Motherland.

You might as well declare the Yangtse a dead river. Dams on the Yangtse are mostly constructed by the Three Gorges Project Corporation, responsible for the building of the colossal Three Gorges Dam and Xiluodu Dam. Where to start on the Yangtse? There are so many large dams under construction or on the drawing board that you have to wonder how anything—or anybody—will survive along this river. So give the Yangtse an F—for Failed River. Why? At times the Yangtse fails to reach the sea. For reasons of pollution, farmers may not use Yangtse water for agriculture — instead favouring groundwater. But even more important, due to megadams stemming the flow of silt, the river fails to deliver nutrients to crops. 

The Damage Done

The first big dam disruption to riverine ecosystems is dredging of sand and gravel. Megadams are mostly made of concrete, and the key ingredients for concrete are found right in the river itself. Of the different kinds of sand—from desert, beach and river—only the latter is valued. Desert sand is too fine; beach sand contains salt, which will corrode metal—cleaning the salt out is expensive. By far the best sand for construction is river sand. Giant barges on the rivers of Tibet dredge up sand, destabilizing fish habitats, and causing erosion at the river banks. 

The next problem is fish. Many fish species migrate to spawn. Where a megadam goes up, ancient fish migration routes are blocked.  Chinese engineers may make vague promises about installing fish ladders at a megadam, but mostly, nothing is done to accommodate fish species.  A more serious blockage involves silt (fine sediment). There is little or no mechanism for releasing silt from Chinese megadams to feed downstream regions. Once or twice a year, silt may be released at a megadam in a spectacular surge of brown. The reason this is done is because silt can clog up the dam’s turbines.

Lawa Megadam is under construction on the Yangtse, which, like the Yellow River, is sourced in Tibet and flows east into China. However, a dozen other rivers sourced in Tibet have transboundary flows into other nations—ranging from Pakistan in western Asia to Vietnam in eastern Asia.

Green Light, Green Dams

China uses standard arguments to defend its frenzy of dam-building not only in Tibet, but across Asia—and indeed, across the globe. China’s spin doctors often argue that changes happening to the nations downstream are all due to climate change. But what is the leading cause of climate change anyway? China is. Should be talking about China Change, not Climate Change.

1964 poster: “The magnificent hydro-electric power station on the Xin’an River” shows a Han woman (centre) singing the praises of a large dam to a Tibetan woman (at right) and a Uighur woman (at left). Both Tibet and Xinjiang have suffered heavily from China’s exploitation of their lands.

 

Chinese officials argue that dams are green energy—and lumps dams in with its sustainable energy targets such as solar and wind power. This is a big lie. Large dams are highly destructive to riverine ecosystems. Huge dam reservoirs can produce more toxic methane, nitrous oxide and CO2 in the first decade of use than coal-fired plants. Dams profoundly impact biodiversity, blocking fish migration. Megadams will block the flow of nutrient-rich sediment downstream, starving both wild plants and agriculture of essential elements. Dam building displaces thousands of people to make way for reservoirs.

China claims the rivers sourced in Tibet as sovereign property, and does not care what happens downstream. China has not signed the UN watercourses agreement for sharing of rivers. That’s quite possibly because China wants to divert the water for its own uses. China is running out of water—in particular, groundwater. Tibet has an abundance of both river water and groundwater. The solution to China’s thirst is to divert water from Tibet via megadams. Fracking and oil-sands extraction—which will probably start up in Sichuan, Qinghai and Xinjiang—will require huge quantities of water.

Downstream Blues

China’s biggest overseas dam-builder is state-run SinoHydro, headquartered in Beijing. SinoHydro will step in where Western corporations fear to tread—dodging ethical minefields, and proceeding to build with no Environmental Impact Assessments. And corporations like China’s Eximbank conveniently provide the funding for dam construction — again with no questions asked. The resulting megadam may well put the host nation in debt, which is exactly what China wants, because the banks can demand other resources as payback, such as rare wood, copper and other minerals.

SinoHydro has constructed a cascade of seven dams on the Nam Ou River in northern Laos—effectively killing the river, which is a tributary of the Mekong. Down the other end of the nation, on the Mekong mainstream, SinoHydro is completing Don Sahong Dam, which will kill off the last habitat of the Irrawaddy Dolphin in Laos. Laos does not need the power from a dam like this: it is being built to generate foreign revenue, as most of dam power will be exported to Thailand and Vietnam. 

Don Sahong Dam, nearing completion on the Mekong mainstream in Laos.

All dams in Cambodia are built by Chinese cronies of prime minister Hun Sen, who is in China’s pocket. Any dam on the Mekong will threaten Cambodia’s abundant fishing in Lake Tonle Sap, which could prove disastrous as Cambodians get most of their protein from fish. Starting its turbines in early 2019 is Lower Sesan 2 Dam, the largest in Cambodia at 400MW output—and the longest dam in Asia, at 6.5km in length. The dam, sited on a vital feeder for the Mekong, is a joint-venture by China’s Hydrolancang International, Cambodian company Royal Group, and Vietnamese company Vietnam Electricity.

Who is going to stop China from wrecking the rivers of Tibet—and the entire ecosystems that go with them? Feisty Chinese environmental activists and NGOs offer a ray of hope. One NGO took the unprecedented step of suing a State-run dam-builder in Yunnan for breaking its promises with the local community. Or to rephrase that, not fulfilling its promises to the local community. A group of Chinese NGOs managed to shut down plans a cascade of 13 megadams on the Salween River in Yunnan. But the dam-builder is still waiting in the wings, ready to move in. Meantime, downstream on the Salween, in Burma, Chinese dam-builders are moving in to construct dams there.

By far the world’s biggest dam-builder, Chinese corporations have a portfolio of over 300 large dams in 74 countries. Only a handful of these dam projects have been suspended or cancelled due to protest. In northern Burma, on the Irrawaddy River, Chinese engineers hit a rare speed-bump. Ethnic Kachin protesters have waged a long campaign against building of colossal 6-GW Myitsone Dam. The dam was stopped in its tracks due to fierce protest. But the Chinese engineers have not abandoned it. They are biding their time, waiting to the situation to change. Massive protests near the site in April 2019 show the Kachin protesters are digging in for a long fight. 

 

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