The Bhutanese Leading the way.
The Dagachhu Hydropower Project, which has remained non-operational since October 2025 after severe monsoon flooding damaged several critical components, is now preparing to resume operations, according to the Ministry of Energy and Natural Resources (MoENR).
The Director General (DG) of the Department of Energy, Karma Penjor Dorji, said the flooding on 5th October 2025 exceeded 1,300 cubic metres per second, far surpassing the project’s design flood capacity of about 859 cubic metres per second. The event, described as a one-in-10,000-year return period flood, triggered severe toe erosion below the headrace channel alignment, leading to continuous slope displacement and extensive structural damage.
The flood caused the failure of the headrace channel (HRC), washed away access roads, and damaged downstream structures including the gantry crane, stop logs, wing walls, log boom and fish ladder. Following the incident, the plant was shut down due to the scale of the damage and the need for long-term stabilization measures.
According to the DG, the prolonged shutdown resulted in generation losses amounting to approximately Nu 655 million, equivalent to 192.35 million units of energy.
To restore the project, three Bhutanese contractors were engaged for various works. Yoezer Engineers carried out slope stabilization works below the headrace channel, restoration of access roads and river training works. Vajra Builders undertook civil works and construction of saddles for the headrace pipes, while BHSL was responsible for hydro-mechanical works.
The DG stated that major restoration activities have now been completed. Access roads to the weir and powerhouse have been restored, while stabilization works below the HRC included stabilization of HRC benches, construction of gabion walls and drainage systems, reinforced concrete saddle blocks, completion of the transition block, and installation of 243 metres of steel pipe along with expansion joints.
The water conductor system, in line with SNC-Lavalin’s Guidelines for Initial Filling and Dewatering of the Water Conductor System issued in November 2013, is scheduled to begin on 9th May 2026.
The refilling process is expected to take about a week as water filling will be carried out gradually. The spinning of the machine is scheduled for 16th May 2026, signaling the likely resumption of operations at the hydropower plant after more than seven months of shutdown.
