The catchment area of Upper Tamor Hydropower Project is 1850 km2. The design discharge of the Project is 69 m3/s, which corresponds to 42.4% exceedance flow. This results in an installed capacity of 285 MW. The 121 m long (overall) concrete gravity dam has its crest level at 1364 m above mean sea level (amsl). Five gated undersluices have been proposed to provide safe passage of the bed load and floating debris. The intake comprises of 4 orfices, which withdraws the design discharge as well as guides the flow towards gravel trap and successively towards the settling basin. A surface settling basin with three 195 m long gated chambers have been considered to suspend a significant part of the sediment load and to convey the flow to the head pond and/or headrace culvert. A 8730 m long with a diameter of 7.4m headrace tunnel has been envisioned at Tapethok to convey the flow to the surge tank. The surge shaft proposed at the end of the headrace tunnel to accommodate the generated surge has been envisioned in Thauwa of Linkhim VDC. An inclined shaft of 4 m internal diameter conveys the flow from the surge shaft to the five generating units inside the powerhouse by branching into five before entering the Powerhouse. The underground powerhouse is located inside a rock cliff at the left bank of Tamor River at Sisne. The Powerhouse will be connected to an access tunnel (607 m long, 7 m excavation dia.), ventilation and lighting etc. will be provided in the Powerhouse. The Powerhouse will be divided into two caverns: Generation cavern and Transformer cavern. The main cavern i.e. powerhouse/generator cavern consist of five Pelton turbines with same number of generator units. The cavern consists of erection bay for installation and maintenance of electromechanical equipment. After energy generation, the flow is discharged back into the Tamor River via an inverted D-shaped tailrace tunnel. Power evacuation from the powerhouse is planned through 5 km long 220kV double circuit transmission line to Middle Tamor Hydropower Project and then via a 12 km long 220kV double circuit transmission line to Dhungesanghu Substation, as proposed by the NEA.   


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