China warns of high risk of barrier lake breach near Nepal border

China’s Ministry of Water Resources has reported the formation of a large barrier lake near the confluence of the Chhochen Khola and Purepu Tsangpo rivers in Tibet, close to Nepal’s northern border.

A barrier lake is a body of water formed when a natural phenomenon like a landslide, mudslide, lava flow, or glacier blocks the flow of a river or stream.

According to Chinese authorities, the lake had accumulated around 2 million cubic meters of water by Thursday morning, and water had already begun flowing out of the lake. A further 3 million cubic meters of water is expected to enter the lake over the next three days, raising the risk of a possible breach.

China Central Television reported that the ministry is closely monitoring the lake and conducting flood simulations and risk assessments to prepare for a potential breach. It is also making preparations to support emergency rescue operations if necessary.

The Chhochen Khola and Purepu Tsangpo are upper tributaries of the river system that becomes the Bhotekoshi and ultimately contributes to the Trishuli River after entering Nepal. The rivers originate in Tibet and flow toward Nepal through the Himalayan region.

The reported development has raised concerns in Nepal about possible downstream flooding and other hazards in the border region. It therefore remains a situation requiring close monitoring, particularly because any sudden breach could send again a large volume of water downstream toward areas of Nepal.

The broader Himalayan region remains vulnerable to climate-related hazards, including glacier melt, ice-rock fragmentation and avalanches. While several glacial lakes and potentially hazardous areas are being studied, experts say it is difficult to predict exactly where future incidents could occur.