The danger from proposed hydel dam on Yarlung Zangbo in Tibet

Chinese honor guards wearing masks to protect agains the coronavirus are seen near the portrait of late leader Mao Zedong during a ceremony held at the Monument to the People's Heroes on Tiananmen Square in Beijing on Wednesday, Sept. 30, 2020. Negative perceptions of China have increased sharply in many of the world's advanced economies, especially in Australia and the U.K., a new survey from the Pew Research Center showed Tuesday, Oct. 6, 2020. (AP Photo/Ng Han Guan)

Ending years of speculation, China has finally announced its grandiose plans to harness 60 gigawatt of hydropower capacity from Yarlung Tsangpo in Tibet, which happens to be the world’s highest altitude river. Predictably, it has fuelled concerns in India since the river is the biggest tributary of the Brahmaputra and the proposed jumbo scheme is close to the border of Arunachal Pradesh.

It may be too early to delve on the precise impact of the project on the downstream region. Still, a few effects based on the conclusions drawn so far from other hydropower projects can be safely postulated.

Contrary to the concerns raised by some quarters, the water flow in the Brahmaputra River is unlikely to be affected to a noticeable degree given that glacial melt in the river flow contributes only about 12 percent of the total volume of water. The river joins the Dibang, Subansiri and Lohit to form the main channel of the big river. However, the entire stretch of the 294.5 kilometres through which Siang flows in Arunachal Pradesh with a catchment area of about 15,000 square-kilometres could be adversely impacted.

Studies conducted on hydropower projects across different countries have revealed that the quality of water suffered resulting in the decrease of the overall oxygen content. Reservoirs go through a process called ‘eutrophication’ or the enrichment of water with nitrogen and phosphorous and are often breeding grounds of algal blooms. Coupled with these phenomena is the accumulation of thermal energy in the top layers of the reservoirs which combine to produce a negative effect on aquatic life. The Tibetan rivers are known for many endangered species of fish, such as Mahseer which could be wiped out altogether from the river. India’s Northeast is one of several biodiversity hotspots in the world.

The Indian government is of the view that hydropower projects would contribute towards mitigation of flood in the Northeast besides being a source of clean energy which finds mention in the Master Plans compiled by the Brahmaputra Board. However, release of water from the reservoirs of dams had been a primary cause of floods in the Northeast. Proponents of these mega schemes have always been on the back foot when confronted with facts about how dams have caused flood in the region. The best examples come from the dams on Ranganadi River in Arunachal Pradesh and Kopili at Dima Hasao in Assam. Large parts of western Assam were inundated last year and in 2016 after water was released from Kurichun Dam in Bhutan.

The proposed project in Tibet would be much bigger than any of the dams either in the Northeast or Bhutan. It goes without saying that it would be a constant threat to the catchment region of Siang River and downstream districts in Assam such as Dibrugarh. It is also quite unlikely that Beijing would leave the other rivers in Tibet untouched given China’s expanding economy and the increasing need of more water. As many as 10 major rivers of Asia originate in the reservoirs of freshwater in Tibet.

Of course, New Delhi cannot be expected to sit idle while China surges with these projects in Tibet. In 2001, the Central Electricity Authority (CEA) had identified 168 large projects with a potential of 63,328 MW in the Brahmaputra River basin. The surface water resource of the region is around 652.3 billion cubic meters comprising 34 percent of the country’s total water wealth according to a report compiled by the government.

A senior government official was quoted by the media as saying that plans were on to construct a 10 gigawatts hydropower project in Arunachal Pradesh a day after China announced its plans on the dam in Tibet. Recently, officials of the State-owned National Hydroelectric Power Corporation (NHPC) disclosed that the 2,000 megawatt dam on the Subansiri River would be commissioned by March 2022. The delay which was mainly due to the agitation in Assam against the dam has led to an escalation of the project cost from Rs 6,900 crore to Rs 20,000 crore.

Like Subansiri, the government’s plans to construct dams on the Dibang and Tawang rivers had fuelled unrest among the local populace owing to their apprehension of disasters and loss of livelihood.