Brahmaputra Dam Plans Spark Concern as NEHU Geologist Calls for China-India Data Sharing

CORRESPONDENT

SHILLONG: China’s reported plans to build a series of mega dams on the Yarlung Tsangpo, the upper reaches of the Brahmaputra in Tibet, have heightened concerns in India’s Northeast over seismic safety, downstream flooding and ecological disruption. The scale of the proposed intervention has renewed questions about its impact on the Brahmaputra’s natural flow and the communities and ecosystems dependent on the river. NEHU geologist Professor Devesh Walia has called for greater scientific transparency and data sharing between China and India to enable a credible assessment of potential downstream risks.

Walia, of the Department of Geology, North Eastern Hill University, said the Himalayan region’s fragile geology and intense tectonic activity made large dam construction particularly challenging. He stressed that the risks to major dam structures could extend beyond the immediate occurrence of an earthquake and called for detailed, project-specific seismic assessments.

“So we should ask the government of China to share with us all such important data, so that we know the details, practically we cannot go to China and do all these work, so at least they should share with the Government of India, and with the experts it should be shared to know practically what is impact,” Professor Devesh Walia said.

Referring to studies on reservoir-induced seismicity, including those associated with the Koyna region of Maharashtra, Walia said the proposed projects should undergo probabilistic or deterministic seismic hazard analysis tailored to the structures and their geological settings.

He warned that the absence of transparent scientific information could produce sharply divergent assessments of the potential risks, leaving downstream countries to rely on assumptions rather than evidence.

“Otherwise, they’ll say there is no impact and we will think there is impact, so the difference may be 0 to 100 maybe difference. So, we need to fill this gap by proper scientific study,” Walia said.

The geologist said seismic activity was only one aspect of the concern. Given the Himalayan region’s tectonic setting, he cautioned that the structural integrity of large dams could remain at risk before, during and after major seismic events.

“Although when we construct a dam in any of these seismically active areas and Tectonically active areas, and new Tectonic regions, the risk to the dam, the structure, not only during the earthquake, but before the earthquake or after the earthquake, it always remains. So, we have to be very, very cautious constructing dams in such regions,” the geologist said.

Reports of multiple dams being planned along the upper Brahmaputra have further intensified concerns over the cumulative consequences of altering the river’s natural flow. Walia cautioned that changes in upstream water regulation could have significant downstream implications, particularly for Assam, where the Brahmaputra sustains ecosystems, agriculture and river-dependent communities.

He said sudden releases of water from upstream reservoirs could potentially aggravate flooding downstream, while changes in the river’s natural flow could disrupt the wider riverine ecosystem. The concern, therefore, extends beyond the safety of individual dams to the combined hydrological and ecological consequences of multiple projects along the river.

For India’s Northeast, the Brahmaputra is an ecological and economic lifeline, making developments in its upper reaches a matter of regional significance.

Walia’s statement has placed scientific cooperation and transparency at the centre of the debate, arguing that reliable data and independent assessment are essential to understand the potential consequences before they materialise.

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