Glacial collapse unlikely to halt China’s mega dam plan

Why in the News

China is going ahead with construction of a mega dam on the lower reaches of the Yarlung Zangbo, the Brahmaputra, in a seismically active part of Tibet near the border with India. Fresh concerns raised by the glacial collapse along the Nepal-China border have not changed that plan. A month before those flash floods and mudslides, China released its 15th Five-Year Plan for renewable energy, which called for advancing construction of major projects including the Yarlung Zangbo Lower Reaches Hydropower Project. India’s concern is how much water the project will store and how its diversion tunnel will alter downstream flows. Almost nothing about either has been made public, and the one channel through which India receives hydrological data from China has worked irregularly.

What is the Yarlung Zangbo Lower Reaches Hydropower Project?

1. What it is: It is a hydropower complex of five power stations on the lower reaches of the Yarlung Zangbo in Tibet, referred to in China as the mega dam project.
2. How the water is used: Water is taken out of the river at the top of the Great Bend, where the river’s course falls steeply and turns towards India, and carried through a tunnel of about 40 km before rejoining the river below.
3. The scale committed: A total investment of 1.2 trillion Yuan, around ₹14 lakh crore, was announced for the construction of the five power stations at the groundbreaking in July 2025.
4. Who builds and runs it: A new State-run entity, the China Yajiang Group, was set up to run the entire project.

Why has the glacial collapse not changed Beijing’s calculation?

1. The project sits in a standing plan: The renewable energy Five-Year Plan named the project for advancement before the collapse occurred, so the collapse arrived against a target already fixed.
2. Political weight is attached to it: China’s Vice Premier visited Nyingchi in Tibet in April and described it as a landmark mega project of the new era. The Premier had called it the project of the century at the groundbreaking.
3. The safety response is procedural, not a pause: The stated answer to risk is strict enforcement of construction standards and of ecological and environmental protection requirements, with construction progress kept subordinate to quality and safety.
4. Information has been withheld since the start: There has been little public information about the project since the groundbreaking, and the Vice Premier’s visit is what disclosed the new operating company.

What exactly is India concerned about?

1. Storage volume is unknown: How much water will be held in the reservoir is not published, and storage determines how far the timing of downstream flows can be controlled.
2. The tunnel’s effect on flow is unknown: Diverting the river at the top of the bend and returning it below means the natural channel around the bend carries only what the tunnel does not.
3. Wider ecological impact is unassessed: No assessment of downstream ecological effects has been released.
4. The absence of information is itself the obstacle: The lack of published detail prevents India from assessing the impact at all, rather than merely disagreeing with China’s assessment of it.

Why is the run-of-the-river description contested?

1. The label implies no storage: A run-of-the-river scheme passes flow through without holding it back, so it carries limited power to change the timing of water reaching a downstream State.
2. A reservoir is part of the design: The project involves the construction of a reservoir, which a Shanghai-based energy analyst places at the town of Mainling, upstream of Nyingchi, on the basis of reported relocations.
3. The generating configuration is built around drop: The descending force of the diverted water powers five 12-GW powerhouses, which concentrates head rather than passing the river through unchanged.

What does China’s earlier dam on the same river show?

1. The precedent: China has already opened one major dam on the middle reaches of the Yarlung Zangbo at Zangmu, on which construction began in 2010, and a final acceptance meeting was held in June.
2. The output claimed: Zangmu has generated 22.2 billion kilowatt-hours, described as equivalent to saving approximately 7.4 million tonnes of standard coal and cutting carbon dioxide emissions by around 22.2 million tonnes.
3. The regional case made for it: State media said the dam had provided a solution to nearly 26 per cent of electricity demand in the Xizang Autonomous Region, and detailed an elaborate fishway designed to move fish between upstream and downstream sections. The project’s design engineer said the fishway would likely be used for future projects.
4. The new project is of a different order: Chinese analysts project 60 GW of installed capacity and 300 billion kilowatt-hours a year, over three times the Three Gorges, against which Zangmu is small.

How well does the India-China channel on rivers work?

1. The forum exists and is about to meet: India and China will hold a meeting of the Expert-Level Mechanism on Trans-border Rivers later this month.
2. Transmission has been intermittent: The sharing of hydrological data has not been regular and has on occasion been suspended during difficult periods in relations.
3. China’s stated position denies downstream harm: China’s Foreign Ministry has said it maintains a highly responsible attitude toward transboundary river development, that construction is beneficial for disaster prevention and mitigation throughout the entire river basin, and that it will not have adverse effects on downstream areas.
4. Cooperation is described in reporting terms: The Ministry cites hydrological reporting, flood control and disaster reduction cooperation with downstream countries, rather than any joint assessment or consent mechanism.

Challenges to the Yarlung Zangbo Lower Reaches Hydropower Project

1. Seismic exposure at the Eastern Himalayan syntaxis: The Great Bend sits where the Indian and Eurasian plates converge most sharply, which is among the most earthquake-prone locations in Asia. Eg. The 1950 Assam-Tibet earthquake, of magnitude 8.6, struck this same zone and triggered landslides that blocked and then burst Himalayan river channels.
   The Fix: Publish the seismic design basis and the dam-break inundation modelling for the reach below the project, so downstream authorities can plan against a stated failure scenario.
2. Sediment trapping changes the floodplain downstream: The Brahmaputra carries one of the world’s heaviest sediment loads, and any storage structure holds back part of it. Eg. Majuli, the river island in Assam, has lost a large part of its area to bank erosion as the balance between deposition and scouring has shifted.
   The Fix: Fix a sediment flushing schedule and share the release calendar with the downstream riparian in advance of each flushing operation.
3. There is no treaty, only renewable memoranda: India and China share no water-sharing treaty, and data supply rests on memoranda of understanding that expire and must be renewed. Eg. Flood-season hydrological data for the Brahmaputra was not supplied in 2017, the year of the Doklam standoff.
   The Fix: Convert the memoranda into a standing basin instrument with automatic data transmission that does not lapse with the state of political relations.
4. India’s own detection capacity is thin at the entry point: An anomalous release is useful information only if it is detected before it reaches populated reaches. Eg. Sudden rises and sudden discolouration in the Siang in Arunachal Pradesh have been attributed to upstream activity without independent measurement to confirm the cause.
   The Fix: Build a telemetered gauging network on the Siang and the Lohit reporting in near real time to the Central Water Commission.
5. The gorge is an ecological zone of its own: The Great Bend gorge holds an unusual altitudinal range of habitat compressed into a short distance, and diversion removes water from that reach. Eg. The Yarlung Tsangpo canyon is among the deepest in the world and carries forest types from subtropical to alpine within a few kilometres.
   The Fix: Require publication of an environmental flow regime for the bypassed reach, stating the minimum discharge to be maintained through the year.

Conclusion

The dispute is not yet about water, it is about disclosure. India cannot contest a projection it has not been given. A downstream State that learns a reservoir’s capacity only after commissioning has lost the one point at which design can still be influenced. The meeting of the Expert-Level Mechanism this month is the marker to watch, and the test of it is narrow: whether operating rules are put on the table, or whether the meeting produces another reaffirmation of responsible conduct.

Back2Basics: Expert-Level Mechanism on Trans-border Rivers

1. It is the standing India-China official channel on shared rivers, established in 2006 following an agreement between the two governments.
2. Its declared business is the provision of hydrological information by China during the flood season, and cooperation on emergency management of trans-border rivers.
3. It covers the Brahmaputra and the Sutlej, the two rivers on which separate memoranda of understanding govern data supply.
4. It is a consultative forum with no adjudicatory power, and it does not allocate water between the two countries.

Matching Previous Year Question

“Identify the river of the Indian sub-continent on the basis of the following information: 1. Antecedent drainage system. 2. Flows through three countries. 3. Originates in the Tibetan Plateau; important for irrigation. 4. Does not form distributaries. Select the answer from the following: (a) Brahmaputra (b) Indus (c) Sutlej (d) Teesta”