Officials from the Lang Son Department of Industry and Trade confirmed that a portion of the dam had been breached.

The initial crack was about one meter wide, but since the structure is made of earth, there is a risk that the rupture could expand under pressure from the rising water.

After the incident, water from the reservoir rushed downstream, flooding parts of Tan Tien Commune.

Local authorities had anticipated possible flooding from the prolonged rain and evacuated residents in advance, avoiding casualties.

"Due to the recent heavy rains, many households downstream were relocated to safe areas. So far, there have been no human losses. We are still inspecting residential areas to ensure absolute safety," a representative from the Department of Industry and Trade said.

Deputy Minister of Agriculture and Environment Nguyen Hoang Hiep confirmed he was traveling to the site to inspect the situation and coordinate emergency response efforts.

He said that initial assessments showed no human losses and that local authorities had proactively relocated residents at risk.

According to Hiep, the incident was caused by an abnormal rise in water levels following days of torrential rain due to the effects of Typhoon Matmo (Storm No. 11).

He said that experts are examining whether the water level exceeded design thresholds or if technical weaknesses were involved.

Emergency response activated

The Lang Son Department of Natural Resources and Environment reported that Vice Chairman of the Provincial People’s Committee Doan Thanh Son was at the scene to oversee the response.

Authorities have begun assisting people affected in the downstream areas and are monitoring for additional risks.

Technical specifications of Bac Khe 1 Hydropower Plant:

Investor and operator: Bac Khe 1 Hydropower Joint Stock Company
Total reservoir capacity: 4.774 million cubic meters
Useful capacity: 0.509 million cubic meters
Normal water level: 200 meters
Dead water level: 199 meters
Flood check level: 202.36 meters
Maximum design water level: 202.02 meters
Installed capacity: 2.4 MW

Flood control measures intensified

As heavy rain continues to cause flooding along the Cau, Thuong, and Luc Nam rivers, the Ministry of Agriculture and Environment on October 7 instructed localities to strengthen dike protection and implement emergency flood-prevention measures.

According to the National Center for Hydro-Meteorological Forecasting, water levels on these rivers may exceed Alarm Level 3, posing a high risk of severe flooding and threatening major dike systems.

The ministry urged provincial authorities to monitor flood levels closely, reinforce weak dike sections, and maintain 24-hour patrols.

Local governments must also prepare manpower, materials, and equipment under the “four-on-the-spot” principle to ensure timely response and report any developments promptly to the ministry for coordinated action.

Pham Cong - Vu Diep