The proposed dam in the upper reaches of Arunachal will have a storage capacity of about 10 billion cubic metres. M (BCM), Jal Shakti Minister Gajendra Singh Shekhawat said in an interview. In terms of storage, Indira Sagar Dam is the largest in India at 12.2 BCM.
The proposed dam is expected to involve an investment of approx. 50,000 crore and is part of the proposed Upper Siang multi-purpose storage project which will also generate hydropower.
China’s 14th Five-Year Plan proposes building a massive dam on the Brahmaputra River, known as the Yarlung Tsangpo in China, a development that has raised concerns in India because of its strategic implications. Relations between India and China have deteriorated after soldiers clashed on the Himalayan border in June 2020, in which 20 Indian soldiers were killed.
Low season water in the Brahmaputra comes from melting snow in the mountains on the Tibetan Plateau. India’s plan includes releasing water from the dam to maintain water security in case China builds structures to divert the water. Also, in case of China releasing water from its upper reaches, such a dam would also help in storing water to prevent floods.
Responding to a question about China’s plan to build hydroelectric projects on the Great Bend just above Indian territory, where the Brahmaputra takes a U-turn, Shekhawat said, “We have planned to build a dam at Yingqiong as part of its mitigation. A project has been planned for. Upper parts of Arunachal Pradesh. And probably it is going to be one of the biggest dams in India. We will keep water in it and release it in low season when it won’t rain to provide us (water) protection.
While river runoff (ROR) projects use the seasonal flow of a river to generate electricity, reservoir projects involve water storage, which addresses the risks associated with natural flows and seasonal changes in river water availability. . Of the eight river basins in Arunachal Pradesh, the Subansiri, Lohit and Siang are of strategic importance as they are close to the border with China.
“Dams serve not only for the purpose of irrigation nor for generating electricity; They also act as a mitigation cushion to prevent flooding. Say, if ever water is released from above, we will still have a cushion to control that water release,” Shekhawat said.
According to Indian planners, rainfall in China accounts for only 7% of the flow of the three tributaries of the Brahmaputra—the Subansiri, Siang and Lohit—that originate in China.
“500 BCM (billion cubic metres) of water is flowing in the Brahmaputra river. More than 75% of this comes from our catchment area. That is why we are not affected much by it. But in the non-monsoon season, when the river gets its water from melting ice, our catchment area does not have water. So if they build dams and divert water in the non-monsoon season, it will affect Bangladesh from Arunachal Pradesh. Earlier they (China) had said that they are not doing anything. He later said he was building run-of-the-river hydroelectric projects. And now there is evidence that maybe they can work on water transfer as well,” Shekhawat said.
Of the 2,880 km length of the Brahmaputra river, 1,625 km is in Tibet, 918 km in India and 337 km in Bangladesh. Of the total catchment area of 580,000 km, 50% lies in Tibet, 34% in India and the rest in Bangladesh and Bhutan.
“We have got clarity on other things. There is some small resistance at the local level, which the Arunachal government is working on. The total cost should be approx 50,000 crores. The cost is insignificant. It should be constructed,” Shekhawat said.
India’s north-eastern states and Bhutan have a total hydropower generation capacity of about 58 gigawatts (GW). Of this, Arunachal alone has 50.328GW, which is the highest in India.
Experts say that China’s plans may not have much impact on the Indian side.
“The majority of the flow of the Brahmaputra river in India comes from the rainfall that falls over the Indian territory. So the water that China intends to use will not have any major impact on the river on the Indian side,” said Anjal Prakash, director of research, at the Bharti Institute of Public Policy, Indian School of Business, Hyderabad.