Assam: Subansiri river won’t dry, assures NHPC


Assam Education Minister Ranoj Pegu said that the National Hydroelectric Power Corporation (NHPC) has assured that the Subansiri river, a major source of water and livelihood primarily for the people of Lakhimpur and Dhemaji districts of Assam, will not dry up in future. NHPC’s assurance comes days after a landslide blocked a diversion tunnel at the NHPC’s Lower Subansiri Hydroelectric Power Project stopping the flow of water in the river causing panic and fear among the people.

Minister Ranoj Pegu visited the project site this morning and took stock of the ongoing situation. After the review, the minister said that the river has been flowing normally since 10:30 PM of October 27. The Minister also shared a video on X showing the flow of the river.

In a post on X, the Minister said, “This morning, I visited NHPC LHEP at Gerukamukh to inquire about the Subansiri river drying up on October 27th. During the dam construction, five diversion tunnels were created. With the completion of the dam, four tunnels were closed, leaving one open for river flow. On the 27th, a landslide blocked the mouth of the 5th tunnel, causing a complete river blockage. Due to the lean season, authorities had to wait for the water level to reach 145 meters before it could flow through the release gates, which happened at 10:30 pm. Since then, the river has been flowing normally. NHPC assures that there won’t be future drying up, and the flow will always be maintained.”

Sharing a video from the site, Ranoj Pegu said, “Subansiri river flow through the release gate at the height of 145 meters above the sea level. The opening is of 15 meters.”

Interestingly this is the second landslide at the same location. A similar landslide impacted the project in March.

The diversion tunnel that was blocked by the landslide is responsible for redirecting the Subansiri’s water flow from the dam site to the downstream of the river maintaining a standard water volume in the downstream areas. The sudden stoppage of water and the river going dry triggered panic and concern among the locals. Several organisations protested the construction of the dam, said to be the biggest hydroelectric project undertaken in India so far.

Fishermen who are dependent on the Subansiri river for their livelihood said, “What will we do if the river dries up. There is no other alternative for us.”

A local woman said, “We never thought that the river will dry up some day. We consider the river as our Mother. Because of her we are alive. There will be uncertainty for many if the river dries further. People will suffer a lot if this happens again.”

The 2,000MW Lower Subansiri hydroelectric power project (LSHEP) is located on Subansiri River, which is on the border of, Arunachal Pradesh and Assam.

NHPC Limited commenced construction work of Subansiri Lower Hydroelectric Project in January 2005 after obtaining forest clearance on October 12, 2004. However, due to agitations and protests by local stakeholders, the project construction work was stalled from December 2011 to October 2019. The project construction resumed from October 15, 2019, after the clearance by National Green Tribunal. The project is scheduled to begin operations from March 2024.

NHPC has informed that more than 90% of the total work of the project has already been completed. The construction of all major components, including dam, power house and hydro-mechanical works is fast progressing towards completion.

The remaining work of radial gates will be completed after the monsoon season and electricity generation is expected to begin by the end of Financial Year 2023-24.

On completion, the Subansiri Lower Hydroelectric Project will generate approximately 7,500 million kilowatt-hours of power annually, in a 90%-dependable year, a PIB release of Jun 2023 said.