India plans ‘buffers’ in proposed Arunachal hydropower project to counter ‘China threat’

According to the National Hydropower Corporation (NHPC) report, China’s proposed 60,000 MW hydropower project in Tibet is influencing the design of a proposed hydropower project in Arunachal Pradesh’s Upper Siang district which is still in its planning stage.

• China is continuously harnessing the hydro-potential of the Brahmaputra River, which is affecting its flow, especially for India’s proposed project.
• The design of the proposed project incorporates ‘buffer storage’ of 9 billion cubic metres (or about 9 billion tonnes of water) during monsoonal flow.
• This could act as a store of water worth a year’s flow that would normally be available from the Brahmaputra or buffer against sudden releases.

The Brahmaputra River:

• The Brahmaputra, known as Yarlung Tsangpo in China, is a 2,880 km long trans-border river.
• It originates in the Mansarovar Lake and flows 1,700 km within Tibet, 920 km in Arunachal Pradesh and Assam and 260 km in Bangladesh.
• It accounts for nearly 30% of freshwater resources and 40% of India’s hydropower potential.
• Diverting its flow could mean agricultural impacts downstream in Assam and Arunachal Pradesh.

Geographical Aspects:

• The Yarlung Tsangpo enters India after passing the Great Bend, through Arunachal Pradesh where it is known as Siang/Dihang, then onto Assam where it is called Brahmaputra, and thereafter to Bangladesh where it is named Jamuna. 
• Data suggests that the annual outflow of Yarlung Tsangpo from China is less than that from India’s Brahmaputra.
• As the river crosses the Himalayan Crestline, it receives an annual rainfall of about 2,000-2,100 mm, which results in swelling of the river line while entering India. 
• The Brahmaputra gets mightier as it flows downstream because of the flow contribution of tributaries such as Dibang, Lohit and Subansiri. 
• In terms of sediment flow, the flow volume and discharge are not sufficient to generate and transport the large sediment load that is characteristic of Brahmaputra downstream.
• China completed the Zangmu Dam (510 MW capacity) built on the upper reaches of Brahmaputra in 2010. Three more dams at Dagu (640 MW), Jiacha (320 MW) and Jeixu are currently under construction. 
• The work on Zam hydropower station, which will be the largest dam on the Brahmaputra, too commenced in 2015.

What are the concerns?

The Chinese decision to build more and more dams on Yarlung/Brahmaputra has been an issue of major concern for India. 

• Type of Projects: China, on its part, insists that the dams are and will continue to be run-of-river projects, wherein water will be returned to the river after use. As such there ought to be no fears of diversion, hoarding, and release of water later. This claim was taken with a pinch of salt by the Indian Government.
• Water Hegemony: These dams are large enough to be converted and used as storage dams, especially if the purpose is flood control and irrigation (as is the case with Zangmu Dam). In the absence of a water treaty, China depriving India of water during lean seasons becomes a possibility.
• Flooding: Another risk is the release of flood waters during the monsoon season, which could inundate the already flooded Brahmaputra river basin in Assam. There is much apprehension that the Brahmaputra may lose the silt, which makes the plains in its basin fertile, because of sediment trapping in the dams.
• Seismic Instability: all hydropower projects, particularly around Great Bend, are located in a highly volatile tectonic zone. Their proximity to known geological fault lines, where Indian Plate collides with the Eurasian Plate, makes them extremely earthquake-prone.