‘Chinese dam on Yarlung Tsangpo/Brahmaputra: Should India be concerned?’

In a move that could have long-term impact on northeast India’s water security, China has said it will build a “super” dam on the lower reaches of the Yarlung Zangbo river, close to the Line of Actual Control, in Tibet.

• The China-India hydropolitics over the Yarlung Tsangpo/Brahmaputra has generally been perceived as “hydro-hegemon” China’s ill intent towards downstream India’s interests.
• Earlier, a host of contentions were floated about China’s gravity dam project, the Zangmu Dam on the Yarlung Tsangpo/Brahmaputra system on the northwest of Gyaca in the Tibet Autonomous Region (TAR) of China.
• As such, many such incidents over the Brahmaputra in the Indian boundary have been attributed to China’s evil designs against India.
  • the increase in turbidity and blackening of waters in Tsiang (the name of Yarlung Tsangpo in Arunachal Pradesh)
  • news of a series of check dams being constructed along the Tibetan boundary.
  • temporary stoppage of data sharing by China over the high season flows as per the China-India MoU during the Doklam standoff

• The latest China's decision to build a new dam has raised concerns in India Beijing's inclination to control the flow of Brahmaputra river.

What is the Chinese Plan?

• China is planning to build the dam as part of the proposal for the country's 14th Five-Year Plan that will be implemented next year.
• China has already been formulating the five-year plan for the communist nation, as well as long-term goals through 2035. 
• The dam could come up in the Medog county of Tibet, which is close to Arunachal Pradesh. China has already built several smaller dams on the Yarlung Zangbo.
• The new dam’s ability to generate hydropower could be three times that of central China’s Three Gorges Dam, which has the largest installed hydropower capacity in the world.
• China will “implement hydropower exploitation in the downstream of the Yarlung Zangbo River” (the Tibetan name for Brahmaputra River).
• The project could serve to maintain water resources and domestic security in China.

• The Brahmaputra flows for over 3,000km through Tibet, India and Bangladesh. 
• Brahmaputra river is crucial for India too as its basin is a critical water source for Arunachal Pradesh, Assam, Meghalaya, Sikkim, Nagaland and West Bengal.
• The Brahmaputra valley supports the lives of several indigenous communities.
• The Brahmaputra is an important resource for India’s own water diversion plans – the national river interlinking project – and is considered a powerhouse to meet India’s energy demands in the future.

The gravity of this intervention and its impact on downstream India need to be understood from the perspective of existing hydrological flow and precipitation regimes.

Hydrology and precipitation

• At the very outset, both the hydrology and precipitation over the Yarlung Tsangpo/Brahmaputra are highly correlated, despite the fact that the system is fed by rainfall, as well as snow and glacial melts.
• The contribution of snow and glacial melt to the flow is substantially low in the overall stretch; however, its contribution is higher in the upper reaches of the flow which are in the rain-shadow region.
• Of the total 2,880 kilometres (kms) length of the Yarlung Tsangpo/ Brahmaputra,
  • Tibet (2,880 km): 1,625 kms flows through the Tibetan plateau with the name Yarlung Tsangpo
  • India (918 km): It assumes the names of Siang, Dihang, and Brahmaputra in its 918 kilometres in India
  • Bangladesh (337 km): the rest of the 337 kilometres in Bangladesh is named the Jamuna till its confluence with the Ganges near Goalando.

Maximum flow of the system:

• Though this geographical distribution of length gives an apparent impression that the maximum flow of the system occurs in the TAR of China, it is a myth.
• Rather, the system becomes stronger and fatter as it flows further downstream.
• It needs to be noted here that the Brahmaputra is identified as the flow downstream of the confluence of three tributaries, namely the Luhit, Dibang, and Dihang, near Sadiya in the Indian state of Assam.

Rainfall

• A huge variability is noted in the precipitation and run-offs.
• A large part of the Tibetan component of the basin, i.e. the longer stretch of the Yarlung, is located in the rain-shadow north aspect of the Himalaya, and is therefore a recipient of much less rainfall as compared to the south aspect.
• Therefore, while the average annual precipitation in the trans-Himalaya is around 300 mm, the average annual precipitation (that includes mainly rainfall) reaches about 3,000 mm in the south aspect just after crossing the crestline.
• The foothills are frequently fed by anomalous precipitation of a magnitude that is capable of causing great floods.
• Within the Brahmaputra valley in Assam, the average annual rainfall is higher in the northeastern areas and gradually decreases towards the western parts.
• In the peak flow periods, the Brahmaputra is fed by the monsoon rainfall.

Peak Flow

• While the peak flows at Nuxia and Tsela Dzong — measuring stations at the great bend in the Tibetan plateau — are about 5,000 and 10,000 cubic metres per second (cumecs), the peak flow at Guwahati in Assam is approximately 55,000 cumecs.
• The lean season flow in Nuxia is in the range of 300-500 cumecs, while the lean flow at Pasighat in India is to the tune of 2,000-plus cumecs, the one at Guwahati is around 4000-plus cumecs, and at Bahadurabad it is about 5,000 cumecs.
• Summarily, the annual discharge of 31.2 billion cubic metres (BCM) at Nuxia simply does not compare with annual discharges of Pandu/Guwahati (494 BCM) or that of Bahadurabad in Bangladesh (625 BCM).

Sediment regime

• The sediment regime also follows the same pattern, with the run-off in the rain-shadow region not being sufficient to carry the massive sediment load recorded downstream.
• The Brahamputra’s large mainstream flows of water and sediments are contributed by many of its large tributaries including Dibang, Dihang (Siang), Luhit, Subansiri, Manas, Sankosh, Teesta, etc.
• While Nuxia records an annual suspended sediment load of around 30 million metric tonnes, the same is recorded at 735 million metric tonnes in Bahadurabad.

Potentially utilisable water resources (PUWR)

• The potentially utilisable water resources (PUWR) of the Brahmaputra is barely 25 percent in terms of data from the erstwhile Ministry of Water Resources (presently MoJS).

Therefore, given the precipitation, run-off and sediment flow regimes, it is unlikely that any intervention on the Yarlung Tsangpo in the north aspect of the Himalaya can cause any substantial harm for downstream economies including India and Bangladesh, irrespective of Chinese intent. This is largely true given the location of the Zangmu hydropower project.

• The above conclusion cannot be stated for the present proposed project in the Medog county of TAR.
• This is because, the Medog county in TAR lies in the south aspect of the Himalayas, where the flow of the mainstream Yarlung is enhanced by the flow of another tributary Parlung Tsangpo.
• In Medog, the annual average precipitation is of 3,000 mm, substantially higher than the 500 mm recorded at Nuxia.
• Moreover, there is some dispute with the annual discharge data of the Yarlung at the point of leaving China.
• While estimates by some Chinese scholars state that the dischargeis of the tune of 135.9 BCM, the ministry data suggests the same to be 78.1 BCM.
• The percentage divergence between the two data sets is quite big.
• However, some older estimates in India suggest that the discharge in Tuting in Arunachal Pradesh is 179 BCM.
• Therefore, in percentage terms, the contribution emerging from the Chinese boundary to the immediate point in the Indian boundary cannot be stated to be negligible, though this turns out to be of not much significance to the run-offs in the Assam floodplains in India or the Jamuna floodplains in Bangladesh.

Today, water remains a politically contested issue in much of South Asia.

• Water shortage and rapid urbanization: South Asia is facing water shortage and agrarian difficulties, and this difficulty is likely to continue due to increasing demands on energy and water with rapid industrialisation.
• Over-exploitation: Over-extraction of groundwater is becoming a huge concern, with an estimated 23 million pumps are in use across Bangladesh, India, Nepal and Pakistan.
• Salinity and contamination: Besides, salinity and arsenic contamination affect over 60 percent of groundwater in the Indo-Gangetic plain.
• Climate Change: Combine these factors with the impact of climate change that’s reducing the amount of water in the Brahmaputra basin and changing the patterns of water flow.

Under such circumstances, the increasing need for power and stable water levels could prompt reconsideration in bilateral water-sharing treaties in future.  Freshwater is a precious commodity and a strategic asset whose importance in geopolitics cannot be underestimated.

India now needs to be more adept in responding to Brahmaputra river-related issues.

• Clear vision: India needs to clearly envision the desired end goal and strategic outcomes for dealing with impending water conflicts.
• Re-strengthening relationship: India needs to de-emphasise China’s role and re-strengthen its relationship with Bangladesh by pushing the impending Teesta river agreement.
• Strong negotiations: It needs to mirror its strength and firmness in negotiations with China on water rights, as it did in the case of the Doklam stand-off and in opposing the Belt and Road Initiative, rather than projecting itself as a victim.

Speculation about China planning to build a ‘super hydropower station’ in Medog county, where the Yarlung Zangbo Grand Canyon is located, have circulated for years. Medog, with a population of about 14,000, was China’s last county to be connected to the outside world with a highway. For India, the dam in Medog can have negative impacts on Arunachal Pradesh, but there does not seem to be any impact on Assam and Bangladesh.