Tunnel Testing Of Upper Tamakoshi Resumes

The Upper Tamakoshi Hydropower Project being constructed in Bigu Rural Municipality–1, in Dolakha district, is once again testing its main tunnel.
The project, which is finally nearing completion a decade after construction began, first tested the tunnel on April 29 by sending water through it.
However, the test had to be stopped because of a leak. Water leaked from the cover of a manhole of a penstock pipe connecting the 373-meter lower vertical shaft with the 310-meter upper vertical one.
“The team has repaired the leaking cover and we resumed testing on Monday by once again sending water through the tunnel,” said Dr. Ganesh Neupane, spokesperson for the Tamakoshi Hydel Project, informing that the team had begun testing the civil and hydro-mechanical structures.
With the manhole lid repaired, Neupane informed that the project would move on to testing the adit ( the horizontal passage leading to a mine after the purposes of access or grainage) gates by completely filling the eight-kilometre-long tunnel with water. If the team does not detect any damages, they will route the water to the main shut-off valves (MSOV) through the bifurcation. Then the testing and commissioning of the six turbines and six generators connected to the six units of the underground power house will begin.
“If everything goes as planned, the first unit will start generating 76 Megawatts (MW) of electricity before July,” said Dr. Neupane.
All six units of the hydroelectricity project have a capacity of generating 76 MW each. “Once the first unit comes into operation, the others will follow suit,” Neupane said.
The project was delayed multiple times due to hindrances in digging the 90-degree upper and lower tunnels and installing the penstock pipes.