KATHMANDU: A landslide caused by continuous rainfall has damaged the structures (headworks) at the 456 MW Upper Tamakoshi Hydropower Project, located in Lamabagar of Bigu Rural Municipality-1 in Dolakha.
Due to the increased water flow at Upper Tamakoshi, electricity production was halted from 7 PM on Friday. All gates of the dam have been opened in response to the rising water levels.
Damage has occurred to the control room, sand settling pond (desander), and the canal (culvert) that directs water from the dam to the desander, situated a bit below and to the right of the dam site. It is estimated that significant damage has been caused to these structures due to landslides from higher elevations.
Mohon Gautam, CEO of Upper Tamakoshi Hydropower Limited, stated that flooding in the rivers along the access route from Gongar to the dam has prevented anyone from reaching the site. Gautam noted that based on the nature of the landslide, damage to the control room, desander, and culvert is expected.
A large amount of rocks and sediment has accumulated in the reservoir area due to the landslide. Efforts are underway to rescue two employees trapped in the control room, and so far, there have been no human casualties. The Nepali Army, Nepal Police, and Armed Police Force have been deployed for rescue operations in coordination with the District Administration Office in Dolakha.
The design discharge of the Tamakoshi project is 66 cubic meters per second (cumec). Currently, the flow in the Tamakoshi River at the dam site is at 461 cumec. According to the electricity purchase agreement with the Nepal Electricity Authority, the power plant must shut down when the river flow reaches 250 cumec. After the water flow exceeded 250 cumec around 4 PM on Friday and continued to rise, electricity production was fully suspended at 7 PM.