Cao Bang appears flood peak resonance phenomenon

Due to the influence of storm No. 11, widespread heavy rain has put great pressure on reservoirs in Cao Bang province.

Rainfall concentrated rapidly in the same basin, especially in the area of ​​Bach Dang and Binh Long hydroelectric plants, causing water flow to the lake to increase suddenly, exceeding the flood peak values ​​of previous storm No. 10.

The Bang River is rising very quickly, possibly causing flooding in low-lying areas.

Specifically, at Bach Dang Lake, the water flow is 584 m³/s, higher than the flood peak at storm No. 10 (386 m³/s); Binh Long Lake is forecast to reach 650 m³/s, nearly reaching the old peak (750 m³/s).

The Cao Bang Provincial People's Committee Office informed that rainwater from upstream rushed in quickly, forcing the Binh Long and Bach Dang hydropower reservoirs to open their gates to ensure dam safety. When many reservoirs released water at the same time, the water flow from the reservoirs met the incoming rainwater, causing the river water level to rise higher than normal and rise very quickly. This phenomenon is called "flood peak resonance" - that is, the water waves rushed in at the same time, causing the water level to rise rapidly in a short period of time. This is a natural phenomenon, not a dam break or operational error.

Also due to the heavy rainfall and the rapid increase in water levels in the lakes, the lakes cannot continue to maintain low water levels and must release water to ensure safety. The Chairman of the Cao Bang Provincial People's Committee has directed: "Do not let the lake water level exceed the free overflow threshold, regulate emergency discharge to reduce the speed of lake rise due to rapid flood, and at the same time warn downstream areas as soon as possible."

Cao Bang Provincial People's Committee requested that units provide accurate and continuous information on flood discharge situation; explain that the reason for the rapid rise in river water level is due to the resonance of flood peaks, not due to operational or construction incidents, to avoid spreading false information causing anxiety among the people.

The People's Committees of communes and wards proactively notify and guide people to move away from riverside areas, not to go to river banks, and not to collect property in flooded areas. People in low-lying areas need to stay calm, follow official information, not be subjective but also not panic, and be ready to move when requested by the authorities.

Hydropower plants and authorities are closely monitoring and releasing water according to procedures to reduce pressure on the lake and provide early warning to downstream areas.

Currently, floods on rivers in Cao Bang province are increasing rapidly. It is forecasted that floods on Bang and Gam rivers may peak, possibly above alert level 3.

This is a heavy rain right after the recent days of prolonged heavy rain due to the influence of storm No. 10, many places have saturated soil, rivers, lakes and dams are full of water, there is a very high risk of continued major floods on small streams and upstream; flash floods, landslides in mountainous areas; inundation in low-lying areas.

Cao Bang provincial authorities requested people to urgently evacuate people, property and goods from riverside and low-lying areas; strictly follow the instructions of the government and authorities. At the same time, concentrate resources, mobilize maximum forces with the motto of 4 on-site, at all costs must ensure safety of people's lives, minimize damage to people's property. All vulnerable points, at risk of fractures must be checked, warning signs must be posted, and people must be resolutely not allowed to enter dangerous areas.

Source: https://baotintuc.vn/xa-hoi/cao-bang-xuat-hien-hien-tuong-cong-huong-dinh-lu-20251007150422209.htm