Ignore the scaremongering. China can't turn off Brahmaputra even if it wants
Will China wage a water war against India? For many, China's dam building on the Brahmaputra river evokes the image of a tap that can be turned off at will, leaving millions in Arunachal Pradesh, Assam and Meghalaya thirsting for water by the drying banks of the mighty river. Strategists have argued that this is a real possibility, and one has even written a sci-fi book on it.
The scare reemerged on 1 October when China announced it had blocked a tributary of the Brahmaputra for a dam it has been constructing since 2014. Since this happened within a day of India's "surgical strikes" in Pakistan Occupied Kashmir and murmurs of damming the Indus, the imagery of a water war seemed appropriate.
But can such a war really happen? Fortunately, there is no unanimity on this view.
Experts with knowledge of the river, and of India-China relations, say China's power over the Brahmaputra is exaggerated. There just isn't that much water in the Brahmaputra on the Chinese side as to cause largescale devastation downstream. As for damage from China's damming the river, there are far more dams on the Indian side that can cause greater damage. Indeed, in the downstream areas of Assam, there is greater reservation against India's dams on the river than the Chinese ones, which are fewer in number.
How much water can China control?
The Brahmaputra originates in the Tibetan plateau, where it is known as the Yarlung Tsangpo. Running eastward for about 1,100 km through a dry region, the river makes a dramatic U-turn at the Great Bend, and flows southward into Arunachal, where it is known as Siang. From there, a great volume of water is added to the river by its tributaries such as the Dibang, Subansiri, Lohit and Kameng in India, and the Teesta in Bangladesh.
In fact, far more water is added to the Brahmaputra's flow in India, Bhutan and Bangladesh than in China. According to the Food and Agriculture Organisation's AQUASAT survey of 2011, the annual flow of the Brahmaputra basin from China to India is 165 cubic kilometre, but from India to Bangladesh the flow is 537 cu km. Bhutan alone discharges 78 cu km - half of China's amount - into the river.
According to another study, although 50% of the Brahmaputra basin is in China, it generates just about 22% of the annual water discharge of the river because of the dry weather there. India accounts for 34% of its basin area but contributes 39% of the total discharge. Bhutan covers 6.7% of basin but 21% of the discharge, almost the same as China.
This is why most experts dismiss the fear that China will someday choke the Brahmaputra water supply to India. "There is no question of the Chinese controlling the water flow in the Brahmaputra since most of the water comes from Indian tributaries, that is the monsoon rainfall. The water flow issue is quite overstated and a result of ignorance and prejudice acting together," says Jabin Jacob, fellow at the Institute of Chinese Studies.
Moreover, China has little capacity to hold the water back. The dam on the river it operationalised last year - Zangmo or Zam dam - is a 510 megawatt run-of-the-river dam that doesn't take out any water from the river. The other dams proposed on the river are also of this type.
In fact, the dam for which China blocked a tributary recently - and which has sparked the latest fear of water wars - is Lalho Hydroelectric Project, the first storage reservoir for irrigation; the first dam, that is, which will actually take water out of the river. But this tributary - Xiabuqum - contributes only about 0.02% of the Brahmaputra's flow in China.
Since the other dams aren't of the storage type either, China does not yet have the capacity to block water during the lean season in India, when the Chinese share of water in the river is much higher.