Project Location and Accessibility

Yungichhu hydropower project is a run-off the river scheme planned across Yungichhu. The project is located near Onngar Village in Maedtsho Gewog about 34 km away from Mongar-Lhuentse national highway. Yungichhu is a tributary of Kurichhu which in turn is a tributary of Drangmechhu, the biggest river basin of Bhutan. The catchment area at the intake site is 125 sq.km and the river joins another tributary, Wambur at an elevation of about 1176 masl.

The intake is located at an elevation of 1706 masl and powerhouse is located at an elevation of 1200 masl at the confluence of Yungichhu and Wambur. The intake and powerhouse sites are 12 km away from the Gortshom Gewog center. The project sites are accessible via road from India border towns through four alternative routes; Nganglam, Samdrup Jongkhar, Gelephu and Phuentsholing with the shortest being 217 km from Nganglam-Gyalpoizhing for the transportation of equipment, construction materials, etc.

Field Investigations

Topography survey and mapping was carried out at 1:5000 scale at 5 m contour interval for the whole project area and along the main project components topography survey was carried out at a higher resolution of 1:1000 scale at 1 m contour interval. Geological mapping, geophysics survey and core drilling were carried out for ascertaining the geological conditions of the project area.

Several stages of field visits were carried out to assess the topographical, geological and environmental & social impact assessment of the project layout. A team comprising of three key experts from Bernard Gruppe, Austria who has been recruited as the Consultant for providing technical support for the preparation of FSR and engineers from DGPC carried out the final field assessment of Yungichhu from October 16-18, 2021.  The joint field assessment resulted in finalization of the project layout and development of project construction methodology.

Project Layout & Features

The project is a run-of-the-river power plant located on the right bank of Yungichhu. It envisages a design discharge of 7.46 cumecs, net head of 483 m and corresponding installed capacity of 32 MW. The main components of Yungichhu are raised weir with side intake, surface desilting basins, water conducting system comprising 3626 m surface pipe, 2580 m underground pipe, 83.50 m underground penstock pipe, 1584.5 m surface penstock pipe and surface powerhouse (located at the confluence of Yungichhu and Wambur to accommodate generating equipment).