Wary of China's mega dam, Delhi fast-tracks plans to mitigate effects

A view shows the Siang river in Siang district, Arunachal Pradesh, India, August 1, 2025. — Reuters

India Fast-Tracks Upper Siang Dam as Strategic Counter to China’s Brahmaputra Mega-Dam

Fearing an 85% drop in dry-season river flow due to China’s mega dam on the Brahmaputra, India fast-tracks the Upper Siang project. This article explores environmental, strategic, and geopolitical dimensions.

A view shows the Siang river in Siang district, Arunachal Pradesh, India, August 1, 2025. — ReutersPARONG, INDIA: India fears a planned Chinese mega-dam in Tibet will reduce water flows on a major river by up to 85% during the dry season, according to four sources familiar with the matter...

When China greenlit construction of the world’s largest hydropower dam on the Yarlung Zangbo River in Tibet, downstream riparian nations—India and Bangladesh—quickly registered alarm. The proposed futuristic structure, dubbed a “project of the century,” is set to generate an astounding 300 billion kilowatt-hours, which is roughly triple the output of the Three Gorges Dam The GuardianReuters.

For New Delhi, however, this was more than an engineering marvel—it sparked serious concern. A confidential Indian government analysis suggests that China’s dam could slash downstream water flow during the dry season by up to 85 percent Reuters. That stark number spurred Indian planners to fast-track the Upper Siang Multipurpose Storage Dam—a massive countermeasure projected to hold back 14 billion cubic meters of water, releaseable during dry spells to safeguard water supply and buffer against sudden surges ReutersDawn.

A Strategic Ripple Effect

The implications stretch far beyond megawatt figures. The Yarlung Zangbo morphs into the Siang and then the Brahmaputra once it crosses into Arunachal Pradesh and plunges into Assam—bringing vital water to industrial hubs, farmlands, and tens of millions of people. For agricultural hotspots like Guwahati, a potentially 11% supply drop could spell devastation—unless the Upper Siang dam rise to the occasion ReutersDawn.

Then there’s the question of control. Could Beijing wield water as a geopolitical weapon? India’s fears are grounded in reality: the new Chinese dam lies upstream, with the power to restrict or release water unilaterally—affecting downstream agriculture, industry, and ecological balance. In contrast, India’s Upper Siang project, if kept partially empty (30% buffer), could absorb sudden water surges that might result from deliberate or accidental releases ReutersArab News.

Structural Risks in a Fragile Zone

Let’s talk topography: the “great bend” in Tibet where China’s dam is being constructed is one of the most geologically volatile regions on earth Financial TimesDrishti IAS. Experts warn that high seismic risk could trigger deadly landslides or glacial lake outburst floods—turning a construction marvel into a regional disaster zone. India’s Himalayan territories mirror this instability, adding layers of concern for any dam planned upriver Drishti IASThe New Indian Express.

Furthermore, the dam isn’t a single structure—it’s a cascade of reservoirs. Environmental impact studies cite drastic changes to sediment flow and river morphology, potentially harming fragile ecosystems and local livelihoods along the Brahmaputra basin Drishti IASThe New Indian Express.

A Rocky Road at Home

Despite urgent timelines, India’s Upper Siang dam has hit turbulence. Arunachal Pradesh villagers—primarily from the Adi tribe—have resisted regional dam efforts for decades. Their objections go beyond politics: many villages fear submersion, forced relocation, and loss of ancestral land, crops, and cultural heritage Arab NewsLEA Watch News.

Protestors damaged government surveying equipment, blocked roads, and demanded generous compensation or cancellation. State officials insist plans are moving forward, promising $3 million in compensation and emergency infrastructure to support relocation Arab News.

Missing Data and Muffled Diplomacy

On the diplomatic front, India’s leverage is limited. China has increasingly withheld hydrological data, halting even basic treaty mechanisms. The Brahmaputra MoU—intended for water data sharing since 2002—expired in June 2023, while earlier protocols on other rivers lapsed without renewal India TodayThe Financial Express.

India has urged Beijing, under existing Expert Level Mechanisms, to at least resume data flows and engage in collective risk planning. But cooperation has been patchy, and trust remains low. Consequently, India is ramping up internal capabilities for environmental modeling, early warning systems, and diplomatic outreach to Bangladesh to build regional resilience The Financial ExpressIndia Today.

Regional Ripples Beyond India

The ramifications don’t end at India’s borders. Downstream Bangladesh, too, is sensitive to shifts in water flow. Reduced volumes could boost salinity in coastal areas, disrupt farming, and devastate fisheries. Many agricultural communities rely on the Brahmaputra for their livelihoods India Today.

By accelerating infrastructure planning and fostering regional engagement, India hopes to shift the narrative from reactive risk to proactive cooperation. Yet, without a binding treaty, these moves remain slow and uncertain.

What India Must Do

1. Accelerate the Upper Siang dam, maintaining empty buffers for sudden surges.
2. Push for renewed water-sharing treaties, using diplomatic pressure and UN platforms to advocate equitable access.
3. Invest in interlinking rivers, like linking Brahmaputra tributaries to the Ganga basin, offering flexibility during floods or drought.
4. Build predictive analytics frameworks, with real-time modeling and early warning systems.
5. Engage downstream neighbors like Bangladesh and Bhutan for coordinated disaster preparation and data sharing.
6. Monitor seismic threats, install robust safety monitoring across transboundary river systems.

Water’s New Frontier

What’s unfolding is not merely a contest of hydro-engineering—it’s a race for water sovereignty, national security, and regional stability. In an era of climate extremes and growing resource stress, rivers like the Brahmaputra become more than water—they are life itself. India’s bid to fast-track the Upper Siang project is a sober reminder that when water flows, so do borders, economies, and futures.

FAQs

1. What is China’s mega dam on the Brahmaputra?
China’s mega dam, built on the Yarlung Zangbo River in Tibet, is designed to generate 300 billion kilowatt-hours of hydroelectric power, making it one of the largest hydropower projects in the world. It has raised concerns for downstream countries like India and Bangladesh due to potential changes in water flow.

2. Why is India concerned about the mega dam?
India fears that the dam could reduce dry-season water flow by up to 85%, affecting agriculture, drinking water, hydropower, and ecological balance in Arunachal Pradesh, Assam, and other downstream regions. The strategic concern also includes potential geopolitical leverage China could exert through water control.

3. What is the Upper Siang dam project?
India’s Upper Siang Multipurpose Storage Dam is being fast-tracked as a countermeasure. It aims to store 14 billion cubic meters of water to regulate river flow, mitigate floods, and ensure a reliable water supply for agriculture and urban centers downstream.

4. How could the dam affect local communities in Arunachal Pradesh?
The Upper Siang dam could submerge villages and require relocation of local communities, particularly tribal groups like the Adi. The government has proposed compensation and infrastructure support for affected residents, but protests and objections remain significant.

5. How does China’s dam impact Bangladesh?
Reduced river flow from the Brahmaputra could increase salinity in Bangladesh’s coastal areas, harm agriculture, and affect fisheries. Both countries depend on predictable water flow for economic and ecological stability.

6. What measures is India taking beyond building the dam?
India is strengthening early warning systems, predictive modeling, interlinking rivers for flexibility, and diplomatic efforts to revive water-sharing treaties with China and coordinate with Bangladesh to manage flood and drought risks.

7. Are there environmental risks associated with the mega dams?
Yes. Both dams pose seismic, ecological, and sedimentation risks. China’s dam is in a geologically volatile region, while the Upper Siang project affects sensitive river ecosystems and biodiversity in Arunachal Pradesh.

8. What is the geopolitical significance of these dams?
Control over transboundary rivers is a strategic tool. India’s Upper Siang dam ensures water sovereignty and security in the face of upstream projects by China, helping maintain regional stability.

9. When is the Upper Siang dam expected to be operational?
The project is fast-tracked, but exact timelines depend on construction progress, environmental clearances, and resolution of local disputes. It is likely to become a crucial water management structure in the next few years.

10. How can citizens stay informed about river and flood risks?
Authorities encourage residents in flood-prone areas to follow NDMA alerts, monitor local news, and adhere to government advisories during heavy rainfall or unexpected water releases from dams.