India’s northeast, a region already battered by seasonal monsoon floods, today faces a new and more uncertain hydrological threat — one that stems not from traditional scarcity, but from growing variability in water availability, driven by climate change, engineering interventions, and geopolitical tensions. In particular, the proposed hydroelectric dam by China on the Yarlung Tsangpo (upper Brahmaputra) has triggered concerns in India about the potential for strategic manipulation of water flows and the heightened risks of sudden water surges into downstream regions such as Arunachal Pradesh and Assam.
China’s Yarlung Tsangpo Dam: Strategic Infrastructure on a Fragile River
China has announced plans to build a massive hydroelectric project on the Yarlung Tsangpo, the upper stream of the Brahmaputra River, in the Medog County of Tibet, near the Great Bend — a seismically active and ecologically sensitive area where the river makes a sharp U-turn before entering Arunachal Pradesh.
This proposed dam, part of China’s broader hydropower ambitions under its 14th Five-Year Plan, has sparked intense concern in India. The fear is not just about reduced water flow but also about the potential weaponization of water during conflict, the risk of sudden dam releases, and the impact of a dam failure in a fragile and remote terrain. With no binding treaty between the two nations on transboundary rivers, China’s unilateral construction raises strategic, ecological, and humanitarian questions.
Scientific assessments indicate that while China contributes only about 30% of the Brahmaputra’s water volume, its control over the headwaters gives it disproportionate influence over seasonal timing, flood peaks, and sediment flow, all of which are crucial to agriculture and ecology downstream in India.
Comparing the East and the West: Brahmaputra vs Indus Waters
India’s challenges as a lower riparian state exist both in the east with China and in the west with Pakistan. However, the nature of these hydrological relationships differs sharply.
In the West, the Indus Waters Treaty (IWT) of 1960, brokered by the World Bank, provides a robust legal framework for the management of water sharing between India and Pakistan. Despite recurring tensions, this treaty has endured and includes mechanisms for dispute resolution, technical assessments, and notification of projects.
In contrast, in the East, no such treaty exists between India and China over the Brahmaputra. There are only non-binding Memoranda of Understanding (MoUs) that allow for limited hydrological data sharing during flood seasons. This makes India’s position more vulnerable to unilateral decisions made upstream in Tibet.
Thus, while the Indus system is governed but politically tense, the Brahmaputra system is strategically opaque and legally unregulated, placing northeastern India at higher risk.
Climate Change: Shifting the Nature of Water Disputes
Traditionally, water disputes revolved around absolute scarcity — the division of fixed water quantities between regions or states. However, the impact of climate change has fundamentally altered the nature of these disputes. In the Himalayan region, the new concern is variability — when, where, and how much water arrives has become increasingly erratic and unpredictable.
Glacier retreat, glacial lake outburst floods (GLOFs), intensifying monsoons, and cloudbursts are now routine phenomena across the eastern Himalayas. These climate-induced shifts in river flow behavior reduce the predictability on which dam operations, irrigation planning, and disaster response systems were once based.
For a river like the Brahmaputra, this means more frequent and intense surges, leading to floods in places like Assam that can no longer be dismissed as annual monsoon occurrences. These surges are often not natural alone — they may be exacerbated or triggered by uncoordinated dam releases or infrastructure failure upstream.
Arunachal and Assam: Living on the Edge of Surge Risk
The states of Arunachal Pradesh and Assam, both dependent on the Brahmaputra and its tributaries, have always been flood-prone due to their terrain and river systems. But in recent years, they have begun to experience sudden, high-volume surges — water flows that arrive not gradually, but in violent, unannounced torrents.
These surge events are caused by:
Sudden releases from dams, often without sufficient downstream coordination,
Engineering errors or infrastructure stress in high-altitude projects,
Climate-induced hazards such as GLOFs or intense rainfall within a short time window.
These sudden floods are far more destructive than seasonal ones, as they overwhelm embankments, wipe out villages, and cripple transport and health systems. In Assam, already grappling with land erosion and siltation, such floods can have cascading economic, social, and ecological consequences.
Low-Capacity Dams: A Safer Alternative for the Himalayan Terrain
Given the fragility of the Himalayan ecosystem and its seismic vulnerability, experts advocate that if dams must be constructed, they should be low-capacity, run-of-the-river type structures rather than large storage dams.
Large dams in the Himalayas pose:
High risk of earthquake-induced failure,
Disruption of natural river flows and sediment cycles,
Threat of catastrophic flooding in case of structural breach,
Major displacement and biodiversity loss.
On the other hand, smaller dams and diversion-based projects can:
Minimize ecological and social impacts,
Be more adaptable to sudden climatic shifts,
Avoid accumulation of massive reservoirs prone to seismic or glacial events.
This approach aligns with a more sustainable and risk-sensitive model of hydropower generation, especially in sensitive river systems like the Siang, Subansiri, and Dibang in Arunachal Pradesh.
Conclusion
India’s eastern Himalayan region is entering an era of hydrological uncertainty, shaped by geopolitical maneuvering, climatic volatility, and infrastructure-led interventions. China’s plan to build a hydroelectric dam on the Yarlung Tsangpo (Brahmaputra) has highlighted the growing strategic complexity of water in this region. The absence of a legal framework, combined with the unpredictable behavior of climate-stressed river systems, places downstream states like Arunachal Pradesh and Assam at considerable risk.
Moving forward, India must urgently invest in:
Real-time water flow monitoring, especially in transboundary zones,
Bilateral water-sharing frameworks with China,
Resilient infrastructure, prioritizing low-impact dams,
And a comprehensive disaster preparedness strategy for surge-prone river valleys.
Water, once seen as a source of abundance and renewal, is now at the crossroads of security, sovereignty, and survival in India’s northeast.