The unpredictable floods that washed away communities in Nepal in August 2026 offer a preview of what could happen to Bangladesh if transboundary rivers overflow, breaching upstream dams in India.
India has recently kept stalled the implementation of a $13-billion power and water storage project called Siang Upper Multipurpose Project (SUMP) in Arunachal Pradesh, paying attention to local protests. Bangladesh would be affected by any such project that disrupts the flow of the common rivers. The number of such transboundary rivers is 54.
We in Bangladesh have no official data on exactly how many dams, barrages or artificial infrastructure have already been constructed upstream to withdraw waters or generate hydropower. India is unwilling to consult Bangladesh as a co-riparian country for sharing or diverting waters of the common rivers.
New Delhi does not face as much international criticism as it deserves for the drying up of rivers downstream. Because of India's unilateral withdrawal of waters, the world is likely to see a unique delta on the coast of Bay of Bengal lose its distinct character.
Bangladesh and India have only one agreement related to a river -- the Ganges Water-sharing Treaty 1996 -- which is going to expire later this year.
The SUMP runs the risk of causing significant hydrological, ecological, and strategic damage to the downstream areas in the Indian state of Assam and also Bangladesh. Designed to produce up to 11,000 megawatts of electricity, it has reportedly been conceived to regulate river flow and act as a water buffer against China's massive upstream Medog Project on the Yarlung Tsangpo.
We come across claims in favour of construction of the dam as a major component of the SUMP. The dam is 'designed to release stored water during dry months, stabilising minimum water levels and ensuring more reliable freshwater availability for agriculture and domestic use in Assam and downstream into Bangladesh.' Independent hydrologists believe it involves risks of downstream water surges during hydropeaking and massive siltation of riverbeds.
If infrastructure components like the SUMP can mitigate glacial lake outbursts or deliberate water releases by China, what is New Delhi's moral argument for opposing downstream development projects such as Bangladesh's Teesta Barrage project?
Also, if the planned SUMP's massive reservoir volume is meant to absorb any shockwave coming from upstream before it hits populated areas in Assam, why are local communities suspicious? Media reports say local groups like the Siang Indigenous Farmer's Forum (SIFF) and Adi Banne Kebang (ABK) are resisting the pre-feasibility surveys, citing fears of mass displacement, submergence of villages, and loss of ancestral identity.
India earlier initiated construction of the Tipaimukh Dam on the Barak river, the primary source of the Surma and Kushiyara river systems, considered the lifeline of northeastern Bangladesh. The proposed 1,500-MW hydroelectric project in the Indian state of Manipur remains suspended due to local environmental protests.
The controversial mega-project in Arunachal is located in a highly active seismic zone, so any structural compromise or sudden operational water release from the huge reservoir may result in catastrophic flash flooding across the Assam plains and downstream regions in Bangladesh.
The SUMP has direct implications for Bangladesh. The Siang river flows directly out of Tibet, where it is known as the Yarlung Tsangpo. As it flows downstream into Assam, it becomes the main channel of the Brahmaputra, which enters Bangladesh and changes its name to Jamuna, which merges into the Padma further downstream. The Siang river system alone supports the livelihoods of an estimated 130 million people in India and Bangladesh.
Therefore, any infrastructure building affecting the flow of transboundary rivers that hampers the interests of lower-riparian Bangladesh needs to be made an essential part of official talks on water-sharing and river management.
Delhi seeks Dhaka's favour to construct an electricity transmission line through Dinajpur to connect Bihar with northeast India, a major source of hydel. The hydroelectricity is produced by making dams on rivers that deprive Bangladesh of its due shares of waters.
Isn't this an act of exploiting the neighbouring country twice or thrice? Delhi, during the Sheikh Hasina rule, provided a line of credit, a component of which was meant for construction of Bangladeshi roads to be used by India without paying transit fees when giving India permission to use Bangladesh territory as a corridor was an unpopular decision.
Proponents of energy cooperation in South Asia argue that the proposed India-Dinajpur cross-border power transmission line may provide Bangladesh scope for importing cheaper hydroelectricity from Nepal and Bhutan, the two countries that need permission to use Indian land for power trade. What would then be the fate of imports of expensive Adani electricity? These people do not question why the BBIN (Bangladesh, Bhutan, India and Nepal) Motor Vehicle Agreement could not be effective despite the hype created around it.
As the countries of the Himalayan region live in the same ecological system and share nature's common resources such as air and water, they have no alternative to cooperating with each other for collective good. It is, however, hard to hope that multilateralism would work to address the water-sharing disputes and stop causing any harm to lower-riparian Bangladesh.
Concerned over China's Medog project upstream of India, New Delhi has the scope to prove good neighbourly behaviour and set an example by striking an umbrella accord for fairly sharing waters of common rivers with Bangladesh.
Khawaza Main Uddin is a journalist. He can be reached at khawaza@gmail.com.