PHPA-II dam block construction comes to a halt

PHPA-II dam block construction comes to a halt

Due to spill of water from coffer dam toward the dam pit, the construction of a dam block at Punatsangchhu Hydroelectric Project Authority-II (PHPA)-II has been halted.

The spill occurred on August 9-11 due to heavy rain, causing construction work to stop. After the water spilt into the dam block site, water level has accumulated to approximately 9,005,000 cubic meters in the dam pit.

An official from the project said that as of now, the water level in the dam pit has decreased to approximately 900,000 cubic meters.

Currently, PHPA-II has reached the deepest foundation base of the dam block. The dam location is at an elevation of 755m and the depth of the dam is 91m.

The Managing Director (MD)of PHPA, R.N Khazanchi, said that the project is waiting for the monsoon to pass in order to clear the water inside the dam pit.

“As soon as the weather clears, we will clear the water and debris,” said the MD.

The official said that it may take more than a month and a half  to clean the water and debris.

The construction of the dam complex is 64% complete as of now.

The work progress of all the components of the project is on schedule except for the power house complex of PHPA-II.

PHPA-II dam block construction comes to a halt

The PHPA-II power house complex is currently being reinforced due to the incident that occurred on March 2 last year when loose soil collapsed inside the downstream surge chamber, killing six Indian labors.

The power house complex consists of a power house cavern, transformer hall and downstream surge chamber.

In total, 16 Indian laborers were trapped inside of whom 10 could escape.

The project engineer said that the power house and transformer hall reinforcement work is being carried out after the incident.

However, works at the chamber are on stop currently.

The reinforcement and strengthening works consist of grouting and rock bolting.

The project official said that 10% of the strengthening works has been completed so far in the power house and hopefully, the strengthening works will complete by July 2018. “We have completed the foundation for the machines.”

The Head Race Tunnel (HRT) of PHPA-II is 11-m in diameter, which is one of the largest in South Asia.

PHPA MD said that PHPA-II is scheduled for completion by 2019 end.

As of July this year, the project has spent Nu 47.88bn out of a total budget of Nu 72.9bn.

“To complete the project we have to spend another Nu 25-26bn,” said the MD.

PHPA-II with a capacity of 1,020MW is located about 20km downstream of Wangduephodrang Bridge. All other project components are situated on the right bank. Its underground power house is 15km downstream of the dam at Kamechu.

Dechen Dolkar from Wangduephodrang