Deputy Leader of the Opposition in the Lok Sabha Gaurav Gogoi has written to Union Minister of Jal Shakti C.R. Patil, expressing serious concerns over the potential downstream implications of the proposed
Siang Upper Multipurpose Project (SUMP) for Assam.
In his letter, Gogoi emphasised that the Siang River is integral to the Brahmaputra basin, sustaining Assam’s agricultural economy, riverine ecosystems and livelihoods. Any major intervention in its flow
regime, he noted, warrants careful assessment of its implications for flood risks, water security and downstream communities.
The MP recalled Assam’s longstanding concerns regarding mega-dam projects in Arunachal Pradesh. In 2014, the then Chief Minister of Assam, Tarun Gogoi, had called for formal consultation with Assam before major dam projects were undertaken in the neighbouring state. In 2015, he withheld support for the proposed Middle Siang project until its benefits to local communities could be demonstrated, emphasising the need for consultation and safeguards for Assam.
Gogoi stressed that while SUMP is being positioned as a strategic response to China’s proposed mega dam on the Yarlung Tsangpo, the interests of downstream communities in Assam must receive equal consideration. The project’s stated objectives of maintaining year-round flows and moderating floods cannot be treated as guaranteed outcomes, particularly in a region vulnerable to extreme rainfall, landslides and glacial lake outburst floods.
Drawing lessons from Assam’s experience with the Lower Subansiri Hydroelectric Project, he highlighted longstanding concerns over sudden water releases, riverbank erosion, flooding and the impact on downstream livelihoods. He also referred to a 2025 study documenting concerns among downstream
communities regarding flooding, declining fisheries and agricultural losses. These experiences, he argued, underline the need for independent assessments, transparent monitoring and meaningful participation of
affected communities.
Gogoi also pointed to the findings of the 2013 Cumulative Impact and Carrying Capacity Study of the Siang Sub-Basin Including Downstream Impacts, which had identified potential ecological and livelihood impacts of the earlier proposed Siang projects, including the consequences of daily winter water releases for river islands such as Kobo Chapori in Assam. Although the study did not assess SUMP in its present form, it reinforces the need for a comprehensive assessment of its potential downstream implications.
In his letter, the MP urged the Ministry to clarify whether the Government of Assam has been formally consulted on SUMP and called for the disclosure of relevant project assessments and hydrological studies.
He sought an independent downstream impact assessment covering Assam, prior consultation with affected communities and experts, and robust coordination and real-time data-sharing between Assam and
Arunachal Pradesh to strengthen flood monitoring and early-warning mechanisms.
Emphasising that flood moderation, dam safety and downstream ecological protection must remain central to the project’s appraisal, Shri Gogoi stated that India’s strategic interests cannot come at the cost of the safety and livelihoods of its downstream populations.
He urged the Union Government to ensure that no irreversible decisions are taken without prior consultation with Assam, an independent assessment of downstream consequences and a transparent process that gives affected communities a meaningful voice.
Gaurav Gogoi writes to Jal Shakti Minister on potential downstream implications of SUMP for Assam.
