Water Resource Associates
A network of consultants in water resources, water quality, hydrology, hydrogeology and flooding.
Feasibility Study of Upper Tama Koshi Hydroelectric Project
Hydrological studies of yield and flood frequency for run-of-river hydroelectric scheme with daily ponding
Background
Water Resource Associates assisted the lead consultant Norconsult International by conducting the hydrology studies in this project. The scheme is located in the Dolakha district of central Nepal, and it is necessary to trek for two days from the nearest road-head at Singati Bajar to reach the project site, located close to the northern border with Tibet. The scheme will harness the Upper Tama Koshi river, which has a mean annual flow of 67 m3/s at the headworks, by means of a 7 km long head race tunnel, a 790 m fall of water through the penstock, an underground power house containing several Pelton wheel turbines, and a tailrace of 3 km. This high head scheme has the potential to produce 350 MW of power, to increase the current supply to Kathmandu and other industrial towns of Nepal.
Flow gauging station on Upper Tama Koshi river at Lamabagar
Site of proposed intake dam
Scope of work by Water Resource Associates Ltd
The scope of work included all those hydrological analyses normally undertaken for a major hydropower design study, including revision of rating curves, flow duration curves, low flow frequency, flood estimates at both the intake headworks and tailrace outlet, and examination of the tributary contributions to the reach between the intake dam and the tailrace outlet.
Investigations were also made of a major tributary, the Rolwaling Khola, which entered the Upper Tama Koshi river midway between the intake dam and the location of the power hose. Due to the higher elevation of its stream channel, it would be possible to divert this flow through a 6.5 km tunnel to the pond upstream of the main intake dam. This would increase the flow available to the main scheme during the dry season by 15 %, under a future Phase 2 development.
Results
Water Resource Associates assisted the lead consultant Norconsult International by conducting the hydrology studies in this project. The scheme is located in the Dolakha district of central Nepal, and it is necessary to trek for two days from the nearest road-head at Singati Bajar to reach the project site, located close to the northern border with Tibet. The scheme will harness the Upper Tama Koshi river, which has a mean annual flow of 67 m3/s at the headworks, by means of a 7 km long head race tunnel, a 790 m fall of water through the penstock, an underground power house containing several Pelton wheel turbines, and a tailrace of 3 km. This high head scheme has the potential to produce 350 MW of power, to increase the current supply to Kathmandu and other industrial towns of Nepal.