At a time when geopolitical competition in resource-poor Asia is sharpening over freshwater, mineral ores and fossil fuels, China's expansionary activities in the hydrocarbon-rich South China Sea have drawn considerable international attention, especially because of their implications for the global maritime order. By contrast, China's frenzy of dam-building to appropriate internationally shared water resources has not attracted a similar level of attention, despite the specter of potential water wars.
China is almost unparalleled as a source of fresh water. Most of the major river systems of Asia originate from the Tibetan plateau, which was annexed by the People's Republic of China soon after its establishment in 1949. Xinjiang, another sprawling region it occupied forcibly, is the source of the Irtysh and Ili rivers, which flow to Kazakhstan and Russia. However, Beijing does not have a single water-sharing pact with the dozen countries located downstream of its rivers because it rejects the concept.
Most of Asia's dams are in China, which boasts slightly more than half of the world's approximately 50,000 large dams. Yet its great dam boom shows no sign of slowing. Indeed, its dam-building program is now largely concentrated in the borderlands on international rivers.
By quietly and opaquely building large dams on transnational rivers, Beijing is presenting a fait accompli to its downstream neighbors. Its latent capability to control cross-border river flows arms it with significant leverage over neighbors -- a leverage it could employ to influence the behavior of those states, including deterring them from challenging its broader regional interests.
Indeed, by seeking to control the spigot for much of Asia's water, China is acquiring such clout that smaller downriver countries in Southeast and Central Asia now use only coded language to express their concerns over Chinese dam building. For example, calling for transparency has become a way of referring obliquely to China, which smaller states are wary of mentioning by name.
On the Mekong river system -- Southeast Asia's lifeblood -- China is building or planning a further 14 dams after completing six. It is also constructing a separate cascade of dams on the last two of its free-flowing rivers -- the Salween (which flows into Myanmar and along the Thai border before entering into the Andaman Sea) and the Yarlung Tsangpo, also known as the Brahmaputra, which is the lifeline of northeastern India and much of Bangladesh.
Add to the picture China's damming of other smaller rivers flowing to neighboring countries, as well as tributaries of major rivers, and it is clear that these dams are set to affect the quality and quantity of downstream flows.
Shift in focus
China recently completed ahead of schedule the world's highest-elevation dam at Zangmu, Tibet, at a cost of $1.6 billion. It is now racing to complete a series of additional dams on the Yarlung Tsangpo, the world's highest-altitude river. China is also turning an important Yarlung Tsangpo tributary, the Lhasa (or Kyichu), into a series of artificial lakes by building six dams in close proximity along a 20km stretch of the river.
Several factors are behind China's drive to tap the resources of international rivers, including an officially drawn link between water and national security, the growing political clout of the state-run hydropower industry, and the rise of water nationalism at a time of increasing water stress in the northern Chinese plains. With dam-building reaching virtual saturation levels in the ethnic Han heartland, the focus has shifted to China's ethnic minority homelands, where major rivers originate.
China's centralized, megaprojects-driven approach to water resources is the antithesis of the situation in another demographic titan, India, where the constitution makes water an issue for state governments and where anti-dam nongovernmental organizations are powerful. Thanks to organized protests, the much-publicized Sardar Sarovar Dam on the Narmada river in western India remains incomplete decades after work began. The largest dam India has built since independence -- the 2,000-megawatt Tehri Dam on the river Bhagirathi -- pales in comparison to gigantic Chinese projects. These include the 22,500-megawatt Three Gorges Dam and Mekong dams such as Xiaowan, which dwarfs the Eiffel Tower in height, and Nuozhadu, which boasts a 190 sq. km reservoir.
Yet the water situation in India is far worse than in China, including in terms of per capita availability. China's population is marginally larger than India's but its internally renewable water resources (2,813 billion cubic meters per year) are almost twice as large as India's. In aggregate water availability, including external inflows (which are sizable in India's case but negligible for the People's Republic), China boasts almost 50% more resources than India.
As China's dam-builders increasingly target transnational rivers, concern is growing among downstream neighbors that Beijing is seeking to turn water into a potential political weapon. China pays little heed to the interests even of friendly countries, from Kazakhstan to Thailand and Cambodia.
To be sure, dams bring important socioeconomic benefits and help to deal with drought or seasonal imbalances in water availability through their water-storage capacity. A river can be dammed in an environmentally considerate manner. But what China is doing is over-damming rivers.
One manifestation of this aggressive approach is the construction of series of dams in close proximity to each other on international rivers such as the Mekong or the Salween just before they flow out of Chinese territory. These cascades of dams, looking like strings of beads on a map, aim to capture large quantities of water.
Keeping the silt
Major dams tend to change water quality and the rate at which it flows, and reduce the amount of nutrient-rich silt that is carried downstream. As the major Asian rivers flow down from forbidding Himalayan heights through the soft, sedimentary rock on the Tibetan plateau, they bring with them high-quality silt -- a lifeline for agriculture, fisheries and marine life. Silt helps to re-fertilize overworked soils in downstream plains, sustains freshwater species and strengthens the aquatic food chain supporting marine life after rivers empty into seas or oceans.
China's upstream damming of rivers originating on the Tibetan plateau is not just obstructing the silt flow to downstream plains; it is also causing the retreat of major deltas. Several scientific studies have underscored the link between extensive silt retention behind upstream dams and the retreat and subsidence of Asia's big deltas, which are home to megacities like Tianjin, Shanghai, Guangzhou, Bangkok, Kolkata and Dhaka. In addition, the fall in freshwater disgorged by rivers into the seas is disturbing the delicate balance of salinity needed in estuaries and beyond to support critical species.
China's reluctance to bind itself to international rules or norms is rooted in the belief that as the source of these rivers it is in a position to reap the benefits of harnessing their water resources, with the costs borne by those downstream. After all, the river-flow hierarchy reflects the geopolitical one, with the most powerful country controlling the headwaters of Asia's major rivers.
In reality, though, China is inflicting environmental costs not just on the states lower down these rivers but on itself. One example is the impact of its upstream water diversions on its own mega-deltas, which are economic centers, making up a substantial proportion of the country's total gross domestic product. Thanks to the diminished amount of silt discharged into the seas, there is less sediment to add to the delta land formed and fortified through sustained release or to prevent underground seepage of saltwater into sweet-water aquifers along the coasts.
More broadly, the Asian delta regions have become "much more vulnerable" to the effects of climate change and sea-level rise, according to the United Nations-sponsored Intergovernmental Panel on Climate Change, the gold standard in climate science.
In this light, the discussion of China's damming activities on the Tibetan plateau should extend beyond the potential diminution of cross-border flows to the likely effects on the quality of river waters, including through silt-movement blockage. Such effects are already evident within China: the loss of nature's gift of highly fertile silt due to the Three Gorges Dam and other upriver dams has forced farmers in the lower Yangtze basin to use more chemical fertilizers, accelerating soil and water degradation.
Renewed efforts are needed in Asia to co-opt China into institutionalized cooperation. Without China on board, it will not be possible to build water cooperation and protect critical ecosystems.
Brahma Chellaney is a geostrategist and the author, most recently, of "Water, Peace, and War."