Subansiri Lower Hydroelectric Project Awaits Approval Amid Safety Concerns

Approval Pending for Subansiri Lower Hydroelectric Project

Guwahati, June 12: The Subansiri Lower Hydroelectric Project is currently pending approval from the National Dam Safety Authority (NDSA) for its commissioning, following a structural issue identified in one of the dam's spillways that has raised safety alarms.

According to official sources, the NDSA is assessing the progress of the grouting work on the left bank. Completion of this work is anticipated to lead to the necessary approval for commissioning.

Grouting involves drilling for foundation consolidation, which is then filled with cement. This process addresses voids created by erosion and scour, ensuring the structure is securely connected to its footings and subsurface piling. In instances where piling lacks adequate bracing, grouting serves to provide long-term reinforcement.

Sources indicated that they expect all necessary work to be finalized by the end of June, after which they anticipate receiving the NDSA's approval for commissioning.

Regarding the structural breach that raised concerns about potential flash floods, sources downplayed the situation, describing it as a minor occurrence.

They noted, “There is some scouring at the lip of spillway No. 6. It is minor and not a cause for alarm. Regular repairs of spillways are standard during the operation of hydroelectric projects. This incident will not affect the commissioning of the project.”

The Subansiri Lower Hydroelectric Project, which is India's second-largest hydropower dam with a capacity of 2,000 MW, had initially planned to commission three units totaling 750 MW in May, but this deadline was not met. Full capacity commissioning is now expected by March 2026.