Gaurav Gogoi asks Centre if Assam was consulted on Siang dam

Assam Pradesh Congress Committee president Gaurav Gogoi has written to Union Jal Shakti minister CR Patil asking whether the Assam government was ever formally consulted on the proposed Siang Upper Multipurpose Project (SUMP) in Arunachal Pradesh, The Assam Tribune reported on Monday.

Gogoi, who is also deputy leader of the Congress in the Lok Sabha, said the Siang is central to the Brahmaputra basin. Any big change to how the river flows, he argued, has to be weighed for its effect on floods, water security and the people living downstream in Assam.

What the letter asks for

According to the report, Gogoi has urged the Union government to:

• say whether Assam has been formally consulted on SUMP;
• make public the project's assessments and hydrological studies;
• commission an independent downstream impact assessment that covers Assam;
• consult affected communities and experts before decisions are taken; and
• set up closer coordination and real-time data-sharing between Assam and Arunachal Pradesh for flood monitoring and early warning.

He asked the Centre to make sure no "irreversible decisions" are taken without these steps.

'Not guaranteed outcomes'

The Centre has presented SUMP, a large reservoir and hydropower project on the Siang, as a strategic answer to China's mega-dam on the Yarlung Tsangpo upstream. Gogoi said downstream interests must get equal weight, and that the project's promises of steady year-round flows and flood moderation "cannot be treated as guaranteed outcomes" in a region prone to extreme rain, landslides and glacial lake outburst floods.

He cited Assam's experience with the Lower Subansiri Hydroelectric Project, where people downstream have long complained about sudden water releases, bank erosion and flooding, and a 2025 study recording concerns over floods, falling fish catches and farm losses.

He also pointed to the 2013 cumulative impact study of the Siang sub-basin, which flagged the effect of daily winter water releases on river islands such as Kobo Chapori in Assam. Gogoi acknowledged that study did not look at SUMP in its current form, but said it shows why a full downstream assessment is needed.

An old Assam concern

Gogoi recalled that his father, then chief minister Tarun Gogoi, had in 2014 sought formal consultation with Assam before big dams were built in Arunachal Pradesh, and in 2015 withheld support for the Middle Siang project until its benefits to local people were shown.

The letter adds an Assam voice to a debate that has so far played out mostly in Arunachal Pradesh, where Adi community groups have protested against pre-feasibility work for the dam. The Jal Shakti ministry has not publicly responded to the letter.