Continuous rainfall has triggered a landslide that has damaged the structures (headworks) of the 456 MW Upper Tamakoshi Hydropower Project located in Lama Bagar, Bigu Rural Municipality-1, Dolakha.

Electricity generation at Upper Tamakoshi was halted from 7 p.m. on Friday after the water flow in the Tamakoshi River surged significantly. All the gates of the dam have been opened.

The control room, sand settling pond (desander), and the culvert carrying water from the dam to the desander—located on the right side just below the dam site—have been damaged. It is estimated that the structures suffered substantial damage due to the landslide that originated from higher up the slope.

Mohan Gautam, the CEO of Upper Tamakoshi Hydropower Ltd., the promoter of the project, stated that no one has been able to reach the dam site due to floods in the streams along the access road from Gongar, where the powerhouse is located, to the dam.

Gautam mentioned that based on the nature of the landslide, it is assumed that the control room, desander, and culvert have been significantly damaged. A large amount of rock and debris has accumulated in the reservoir area due to the landslide.

Efforts are underway to rescue two employees stationed in the control room, and no human casualties have been reported so far. The Nepali Army, Nepal Police, and Armed Police Force have been deployed for rescue operations in Lama Bagar in coordination with the District Administration Office, Dolakha.

The design discharge (water flow) for the Tamakoshi project is 66 cubic meters per second (cumecs), but the water flow at the dam site is currently 461 cumecs. As per the power purchase agreement with the Nepal Electricity Authority, the powerhouse must be shut down once the river flow exceeds 250 cumecs. Since the flow crossed 250 cumecs after 4 p.m. on Friday and continued to increase, electricity generation was fully halted from 7 p.m.