Pondo Water Control Project blocks the river stream in Tibet autonomous region, Oct 26, 2011. [Photo/Xinhua]

LHASA - A major water control project in Southwest China's Tibet autonomous region on Wednesday blocked the river stream, marking the commencement of the dam's main construction.

Pondo Water Control Project, the largest in Tibet, is located in Lhunzhub County, and dammed the Lhasa River at 10:30 am on Wednesday, said Kelsang Tsering, vice-chairman of the regional government.

Comprised of a reservoir and a power station, the project is designed to irrigate 435.2 square kilometers and generate 599 million kilowatt hours of electricity annually.

The project is expected to start operation in 2013.

Trucks unload soil and gravel to block the river stream at Pondo Water Control Project in Tibet, Oct 26, 2011. [Photo/Xinhua]