Project on track despite devastating July 2023 flash flood that claimed 23 lives and severely damaged headworks site

Neten Dorji

Lhuentse—With more than 71 percent of the project completed, the 32MW Yungichhu Hydropower Project in Lhuentse is on track to begin operations by September 2025.

Druk Hydro Energy Limited (DHyE), a subsidiary of Druk Green Power Corporation (DGPC), is developing the project.

More than 83 percent of headworks components, encompassing construction of intake structure, main feeder tunnel, and desilting chamber complex, have been completed.

The Head Race Tunnel (HRT) construction is 74.79 percent complete, while 58.38 percent of the powerhouse complex and 93 percent of the transmission line works have been completed.

Project management officials said that despite challenges such as flash floods, logistical hurdles, and construction material shortages, the project is on schedule.

In July 2023, a devastating flash flood claimed 23 lives and severely damaged the headworks site, a crucial part of the project that was executed with support from de-suups.

To mitigate the impact of the disruptions, DHyE awarded the work to Rigser Construction Private Limited to ensure the project stayed on track.

The collapse of the Kuri-Gongri bridge and the lack of a direct route for transporting construction material further compounded the challenges.

“Without the bridge, we were forced to take a lengthy detour through Samdrupjongkhar,” said a project official.

In addition, poor conditions of feeder road and frequent breakdowns at Dungsam Cement Plant further contributed to material shortages. “Despite these setbacks, the project remains on track” the project official said.

Of the total project cost estimated at Nu 3.66 billion, Nu. 1.735 billion has already been spent.

Key ongoing activities include concreting headworks structures, laying and burying Glass Reinforced Plastic pipes, casting anchor blocks, finishing work on the powerhouse, and installing electromechanical equipment.

The HRT excavation reached a breakthrough in September 2024, despite initial geological challenges and water ingress.

Hydro-mechanical works commenced in April 2024, including the installation of orifice liners, ferrules, and embedded gate parts.

The project official said that DGPC has deployed skilled professionals with necessary experience to oversee and monitor quality assurance of the project.

“The civil contractor has set up a fully functional quality control laboratory at the project site to conduct quality assurance activities, primarily for civil works,” the official said. “Additionally, DGPC has full capabilities at its Hydropower Research and Development Centre located at Rinchentse Tala to support all quality assurance testing and monitoring requirements for hydropower project activities.”

Safety measures at project site

In July 2023, the project intake area experienced a major flood from the Newanchhu, a tributary of Yungichhu.

Although the project area is not located in a flood-prone zone, an outpost station was established upstream of the headworks, due to the flash flood. The station is manned by two personnel from June to September.

“We are also currently installing early warning system equipment upstream of the headworks,” said the project official. “Additionally, protection walls have been built around the intake and powerhouse areas to protect against possible flood risks.”

Other small hydro projects

Meanwhile, the 18MW Suchhu Hydropower Project is 95.1 percent complete and is slated for commissioning in February 2025.

The 54MW Burgangchhu Hydropower Project which is 67.5 percent complete, is expected to be operational by August 2025.

Infrastructure works for five Phase-II small hydropower projects are nearly finished, with main civil work contracts to be awarded by December 2024. The Phase-III small hydropower projects will begin in 2025.